Senior Backend Python Engineer

🏢 Summary: Senior Backend Engineer role focused on owning and designing production-grade backend systems, from ambiguous problem definition through architecture, implementation, and long-term reliability. The position emphasizes strong system design, distributed systems judgment, and hands-on cloud engineering, with full ownership of services in production. This is a product engineering role with end-to-end responsibility across backend architecture, scalability, and operational excellence. 🗂️ Requirements: Senior-level backend engineering experience in production systems, Strong Python proficiency, Experience designing and operating distributed systems, Knowledge of concurrency, failure handling, and data consistency, Hands-on cloud experience (AWS, Azure or similar), Experience with SQL and NoSQL databases, Ability to design data models and perform schema design, Experience with performance tuning and scalability, Ability to design, implement, and operate backend services end-to-end, Experience using AI tools in daily engineering workflow 📃 Skills: Python, AWS, Azure, SQL, NoSQL, Concurrency, DistributedSystems, Async, APIs, Microservices, LLM, TypeScript 🏢 Description: About Shelf Shelf builds software that helps enterprises make AI work in the real world. We care about the hard part: reliable systems, clear operational logic, and production-grade engineering that makes AI useful instead of brittle. Job Description: This role is for a senior backend engineer who can own important systems, not just implement tickets. You will take ambiguous problems, design the right backend approach, ship it, and keep it healthy in production. We want someone who is strong technically, communicates clearly, and has the judgment to make systems simpler, safer, and easier to evolve over time. This is a product engineering role with real ownership from system design through production. Location – Warsaw, work from the office What You Will Own Design and ship backend services, APIs, data flows, and background processing for production systems. Turn vague requirements into concrete technical plans, trade-offs, and execution. Own services after launch: reliability, observability, performance, and incident follow-through. Make sound decisions around system boundaries, data models, interfaces, and scaling paths. Write clear technical specs, architecture notes, and diagrams when they help the team move faster. Work closely with product, frontend, and platform engineers to deliver end-to-end outcomes. Improve engineering leverage with AI tooling, automation, and internal workflows rather than using AI as a gimmick. Raise the quality bar through code review, design review, and pragmatic technical leadership. What Strong Performance Looks Like You reliably move important backend work forward without waiting to be tightly managed. Your systems are easier to operate and easier to change because of your design decisions. You communicate trade-offs clearly and make the team around you more effective. You use AI tools well: to accelerate analysis, implementation, debugging, writing, and repetitive work, while keeping a high verification bar. What We Are Looking For Strong senior-level backend engineering experience in production systems. Strong Python skills and the ability to design clean, maintainable backend code. Good distributed systems judgment: concurrency, failure handling, data consistency, async work, and service boundaries. Hands-on cloud experience in AWS, Azure, or a similar environment. Comfort with SQL and NoSQL systems, schema design, and performance tuning. Ability to go from problem statement to design to production rollout with real ownership. Clear written and verbal communication. You can explain systems, trade-offs, and incidents without hiding behind jargon. AI-native working style. You already use AI tools in your daily engineering workflow and want to keep pushing that further. Strong Plus Experience with LLM-backed systems, search, retrieval, AI infrastructure, or data-heavy pipelines. Working knowledge of TypeScript or the ability to contribute across the stack when needed. Experience shaping technical direction for other engineers, even without formal management responsibility. How We Evaluate Fit We care more about ownership, systems judgment, and learning velocity than a perfect keyword match to our stack. If you are the kind of engineer who can take a messy problem and turn it into a strong production system, we want to talk. What Shelf Offers: B2B contract. Company Stock Options. Hardware: MacBook Pro. Modern technical stack . Develop open-source software . GitHub Copilot subscription. Access to Claude Code, OpenAI Codex, TypingMind, and MCP Servers. Why Shelf: Our Leadership Team has deep knowledge management and AI domain expertise and enterprise SaaS background to execute this plan We love our customers and our customers love us. Ask a Shelf customer why, and they’ll tell you it’s because of our innovative capabilities, rock-solid reliability, they truly enjoy working with our people, but most of all – it’s the improvements they see in their business KPIs. We have raised over $60 million in funding and our investors include Tiger Global, Insight Partners, Connecticut Innovations, and others We have high velocity growth powered by the most innovative product in our category, 3X growth for 3 years in a row We now have over 100 employees in multiple U.S. states and European countries, and we have ambitious hiring goals over the next few months

🏢 Summary: Senior Full Stack Engineer role with end-to-end ownership of user-facing product features across frontend and backend. The position focuses on turning vague product goals into shipped, production-ready solutions with strong product judgment, code quality, and performance. You will work across UI, APIs, and data flows while leveraging AI tools to accelerate development and improve engineering workflows. 🗂️ Requirements: Senior-level experience shipping production web applications, Strong frontend expertise with React and TypeScript or modern equivalent, Ability to design and implement APIs and backend logic, Experience building and maintaining data flows in production systems, Experience instrumenting applications for production monitoring, Ability to write and maintain automated tests, Experience using AI tools in daily development workflow, Strong understanding of performance and reliability in web applications 📃 Skills: React, TypeScript, JavaScript, Python, Node.js, APIs, REST, HTML, CSS, Testing, AI, Git 🏢 Description: About Shelf Shelf builds software that helps enterprises make AI work in the real world. We build products people depend on, which means product judgment, engineering quality, and execution speed all matter at the same time. About the Role This role is for a senior full stack engineer with strong product instincts. You will own meaningful product slices end to end: understand the problem, shape the approach, build the frontend and backend pieces, ship them, and improve them based on real usage. We want someone who is equally comfortable improving a user flow, shaping an API, and closing the loop on quality in production. This is a product engineering role with real end-to-end ownership. Location – Warsaw, work from the office What You Will Own Build and ship user-facing product features across frontend and backend boundaries. Turn rough product goals into practical solutions with good scope, sensible trade-offs, and strong execution. Work comfortably in UI, application logic, APIs, and data flows rather than stopping at team boundaries. Partner closely with product and design while still being able to move when the spec is incomplete. Improve usability, clarity, performance, and reliability, not just feature completeness. Instrument what you ship so we can learn from production behavior and iterate quickly. Use AI tools daily to move faster and help improve internal workflows, tooling, and engineering leverage. Keep the bar high on code quality, testing, and ownership after launch. What Strong Performance Looks Like You can take a vague product problem and turn it into a shipped, well-reasoned solution. Your features feel coherent end-to-end because you care about both implementation and product quality. You do not treat frontend and backend as separate worlds; you use both to solve the actual problem. You bring momentum. Work moves because you are on it. What We Are Looking For Strong senior-level experience shipping production web products. Strong frontend ability with React and TypeScript or an equivalent modern web stack. Real backend ability. You do not need to be backend-only, but you can design and ship APIs, backend logic, and data flows when the product needs it. Strong product sense. You notice awkward flows, weak defaults, and unnecessary complexity, and you improve them. Good judgment about scope, iteration, and technical trade-offs. Clear communication and comfort working across engineering, product, and design. AI-native working style. You already use AI tools as part of daily implementation and problem solving, and you are excited to improve how engineering work gets done. Strong Plus Experience with AI-powered product experiences such as chat, search, recommendations, workflows, or agent-like systems. Experience with Python, Node.js, or both on the backend. Experience owning product areas with limited oversight. Strong feel for performance, accessibility, and production quality in complex web applications. How We Evaluate Fit We care more about end-to-end ownership, product sense, and the ability to ship meaningful work than a perfect match to every framework on paper. If you are the kind of engineer who can make a product better from multiple angles, we want to talk. What Shelf Offers B2B contract. Stock options. MacBook Pro. A strong AI-native engineering environment with modern tools and room to experiment.

🏢 Summary: Senior DevOps / Platform Engineer role focused on owning deployment, reliability, and operational excellence for a Voice AI product in production. The position emphasizes hands-on infrastructure, CI/CD, observability, and running AI-heavy voice systems at scale. The engineer will independently improve production systems, developer workflows, and operational standards. 🗂️ Requirements: Senior-level experience in DevOps, Platform Engineering, SRE, or Infrastructure Engineering, Strong cloud experience with AWS, Azure, or similar, Hands-on experience with Infrastructure as Code, Experience building and maintaining CI/CD pipelines, Strong knowledge of reliability, observability, and incident response practices, Experience operating production systems, Ability to work across infrastructure and backend layers, Experience using AI tools in daily engineering workflows, On-site work in Warsaw 📃 Skills: AWS, Azure, CI/CD, IaC, SRE, DevOps, STT, TTS, STS, Observability, Infrastructure, Cloud, AI 🏢 Description: About Shelf Shelf builds software that helps enterprises make AI work in the real world. For our Voice AI product, that means reliable runtime systems, strong deployment paths, and production infrastructure that lets engineering teams move fast without creating operational chaos. About the role This role is for a senior DevOps / platform engineer who can independently own how our Voice AI product ships and runs. You will work directly with the team building our Voice AI product rather than as part of a generic centralized Platform function. The job is to make deployment, reliability, observability, and operational quality materially better. That includes infrastructure, CI/CD, environments, incident follow-through, and the practical realities of running AI-heavy systems in production. Real hands-on experience deploying voice-related systems such as STT, TTS, or STS workloads is a strong plus because it is highly relevant to the direction of the work. Location – Warsaw, work from the office What You Will Own Improve how Voice AI services are deployed, run, observed, and supported in production. Build and maintain infrastructure as code, CI/CD flows, environment setup, and paved paths that reduce developer friction. Strengthen observability with better logs, metrics, traces, dashboards, and alerts. Improve reliability through better operational standards, incident handling, post-incident follow-through, and practical SLO thinking. Work across application and infrastructure boundaries when that is what the problem requires. Reduce recurring toil through automation, documentation, and better defaults. Make sound trade-offs around cost, security, performance, and speed. Use AI tools aggressively and well to increase your own leverage and improve engineering workflows. What Strong Performance Looks Like The Voice AI team can ship faster and with fewer avoidable operational issues because of your work. The systems you touch become easier to understand, easier to operate, and easier to trust. You do not need heavy management to create momentum; you find important gaps and close them. You handle real production problems without drama and improve the system after the immediate issue is over. What We Are Looking For Strong senior-level experience in platform engineering, DevOps, SRE, infrastructure engineering, or a similar hands-on role. Strong cloud and infrastructure fundamentals in AWS, Azure, or a comparable environment. Real experience with infrastructure as code and modern delivery pipelines. Strong operational judgment around reliability, observability, incident response, and production systems. Comfort moving across layers: infrastructure, backend services, developer workflows, and operational tooling. Clear communication and strong written habits, especially around runbooks, postmortems, and technical decision making. AI-native working style. You already use AI tools in daily engineering work and think in terms of leverage, automation, and better workflows. Strong Plus Real hands-on experience deploying or operating STT, TTS, STS, or similar voice-model workloads. Experience improving developer experience for product teams, not just operating infrastructure in isolation. Experience with security, access control, compliance-minded infrastructure, and pragmatic operational guardrails. Ability to debug problems that cut across application code, infrastructure, and third-party systems. How We Evaluate Fit We care more about independent ownership, systems judgment, and practical operating ability than about a perfect keyword match to every tool we use. If you are the kind of engineer who can step into a messy production environment and make it calmer, faster, and more reliable, we want to talk. What Shelf Offers B2B contract Company Stock Options Hardware: MacBook Pro Modern technical stack . Develop open-source software Premier AI development environment: GitHub Copilot, Claude Code, OpenAI, TypingMind, v0, MCP Servers, plus credits to experiment with emerging AI tools Why Shelf: GenAI will be at least a $4 Trillion market by 2032 and Shelf is a core infrastructure that enables GenAI to be deployed at scale Our Leadership Team has deep knowledge management and AI domain expertise and enterprise SaaS background to execute this plan We've been helping our customers prevent knowledge mismanagement since our founding in 2017 We have raised over $60 million in funding and our investors include Tiger Global, Insight Partners, Connecticut Innovations, and others We have high velocity growth powered by the most innovative product in our category, 3X growth for 3 years in a row We now have over 100 employees in multiple U.S. states and European countries, and we have ambitious hiring goals over the next few months

🏢 Summary: Frontend Engineer role focused on building production-ready Next.js SSR applications that power enterprise AI interfaces at scale. The position involves architecting complex state management, real-time LLM streaming experiences, and high-performance data-heavy UIs integrated with enterprise systems. You will own features end-to-end, ensuring accessibility, security, and performance for mission-critical AI-driven workflows. 🗂️ Requirements: 5+ years frontend engineering experience, 3+ years experience with React and modern JavaScript/TypeScript, Production experience with Next.js SSR applications, Advanced TypeScript expertise, Experience with complex state management in real-time or multi-tenant applications, Experience building enterprise applications with i18n, accessibility, and security standards, Experience building AI/LLM interfaces with streaming or real-time interactions, Proven ability to optimize high-load, data-heavy applications, Strong expertise in modern CSS (Tailwind CSS or CSS-in-JS), Experience with observability and monitoring tools, Experience using AI coding assistants in development, Upper-Intermediate English proficiency 📃 Skills: React, Next.js, TypeScript, JavaScript, SWR, REST, WebSockets, Tailwind, CSS, Storybook, ReactFlow, Highcharts, Playwright, Datadog, Sentry, Elasticsearch, DynamoDB, PostgreSQL, Aurora, AI, LLM 🏢 Description: As a Frontend Engineer at Shelf, you’ll craft the interfaces that make enterprise AI accessible and trustworthy. While others are building chatbots, we’re solving the harder problem: how do you build UIs that help users confidently navigate AI-powered systems processing millions of documents, while maintaining enterprise-grade reliability? You won’t just build React components — you’ll architect production-ready Next.js applications that handle high-load scenarios with complex states, real-time AI streaming, and multiple layers of enterprise functionality. Every interface decision you make directly impacts how knowledge workers at the biggest companies in the market interact with their most critical information. This is frontend engineering at its most demanding. You’ll tackle challenges like building real-time streaming interfaces for LLM responses, architecting state management for concurrent AI operations across multiple tenants, creating accessible interfaces for complex knowledge graphs with thousands of nodes, and ensuring blazing fast interactions even with petabytes of searchable content. Your components will bridge everything from enterprise authentication systems to cutting-edge AI models, requiring both sophisticated technical skills and sharp product instincts. We obsess over frontend quality because we’re building the trust layer for AI itself. When your interfaces gracefully handle edge cases, provide clear feedback during AI processing, and remain performant under load, you’re not just meeting UX standards — you’re directly enabling users to trust AI-powered answers and make critical business decisions with confidence. You’ll work on production SSR applications serving thousands of enterprise users, implementing localization for global markets, ensuring accessibility compliance, and maintaining security standards that pass SOC 2 audits. Your code will integrate with our Elasticsearch clusters, DynamoDB tables, and Aurora PostgreSQL databases through the largest park of REST APIs, handling real-time websocket updates for AI streaming and collaborative features. We’re a product company that ships fast without compromising on lasting quality. You’ll work alongside proactive, ever-learning engineers who actively use AI coding assistants (OpenAI Codex, Claude Code) to accelerate development. We build custom MCP servers, implement DSPy pipelines for LLM optimization, and experiment with different AI tools for implementation. In our environment, AI isn’t just what we build — it’s how we build. The best engineers we know are drawn to problems that matter. If you’re excited by the challenge of building interfaces that make the AI revolution actually usable and trustworthy for enterprise users, this role offers the rare combination of technical depth, meaningful impact, and the prestige of solving UX patterns that the industry hasn’t figured out yet. Responsibilities Design and implement production-ready Next.js SSR applications with complex state management, handling high-load scenarios and real-time AI interactions at scale Build interfaces for AI-powered features including streaming LLM responses, semantic search across millions of documents, interactive knowledge graphs, intelligent content recommendations, and AI agentic builders Architect component libraries and maintain our design system in Storybook, ensuring reusability, accessibility, and consistent UX patterns across the platform Develop enterprise-grade functionality including multi-language support, accessibility compliance, cross-browser compatibility, and security implementations that meet SOC 2 standards Create comprehensive technical specifications and component API designs that clearly communicate interface decisions, performance trade-offs, and accessibility considerations Build and optimize data-heavy UIs using React Flow for node-based graphs, Highcharts for analytics visualizations, and custom virtualization for handling large datasets Instrument components for performance monitoring, track Core Web Vitals, implement error boundaries, and build automated visual regression tests with Playwright Take full ownership of the features you build, monitoring their performance in production, optimizing bundle sizes, and ensuring they scale gracefully as user load grows Work with SWR for intelligent data fetching, caching, and revalidation strategies that minimize API calls while keeping UIs responsive and data fresh Integrate with backend services via REST APIs, handle websocket connections for real-time updates, and implement optimistic UI patterns for seamless user experiences Leverage AI coding assistants to accelerate development while maintaining high code quality, and contribute to building internal AI agents that automate frontend workflows Stay current with React ecosystem best practices, Next.js updates, AI UX patterns, and modern frontend architecture—experiment with new approaches and share findings with the team Contribute to our engineering standards and practices through thoughtful code reviews, mentor colleagues on frontend best practices, and actively participate in our culture of continuous learning Requirements Over 5 years of professional frontend engineering experience, including more than 3 years specializing in React and modern JavaScript/TypeScript Production Next.js experience — you’ve built and shipped SSR applications at scale, understand app router patterns, server components, and the trade-offs between SSR, SSG, and CSR Deep TypeScript expertise — you write type-safe code with generics, utility types, and advanced patterns. Complex state management — hands-on experience architecting state solutions for challenging scenarios: real-time collaboration, optimistic updates, multi-tenant data isolation, and large-scale data synchronization Enterprise application development — you’ve built applications with localization (i18n), accessibility, security best practices, and compliance requirements. You understand the complexity beyond “making it work” AI/LLM interface experience — you’ve built interfaces for AI-powered features: streaming token responses, chat UIs, semantic search, or similar real-time AI interactions High-load optimization — proven track record optimizing applications for performance under heavy traffic, large datasets, and concurrent operations. You monitor Core Web Vitals and know how to improve them Modern CSS mastery — strong expertise with Tailwind CSS and/or CSS-in-JS solutions. You can implement pixel-perfect designs while maintaining responsive layouts and dark mode support Write well-structured, testable code with thoughtful component abstractions and clean APIs. You know when to abstract and when to keep it simple Strong problem-solving skills and genuine curiosity — you don’t wait for designs to be perfect but proactively identify UX issues and propose solutions. You’re never satisfied with “good enough” and constantly refine your craft Experience with AI coding assistants (OpenAI Codex, Claude, etc.) and eagerness to push the boundaries of AI-assisted development. Part of this role involves creating AI agents to automate portions of the frontend workflow Familiarity with observability and monitoring tools like Datadog, Sentry, or similar platforms for tracking frontend performance and errors in production Upper-Intermediate or better English skills for technical communication, documentation, and collaborating with distributed teams Present your work effectively both verbally and visually — you can articulate design decisions, create component documentation, and explain technical trade-offs clearly Be a Plus: Experience with React Flow, Highcharts, or other complex data visualization libraries Understanding of Node.js/Python/backend fundamentals — you can read backend code and contribute to API design discussions Experience with SWR, React Query, or similar data fetching libraries Hands-on experience with vector search UIs, RAG interfaces, or semantic search implementations Familiarity with MCP (Model Context Protocol), DSPy, or other cutting-edge AI frameworks Experience with monorepo tools (Lerna, Turborepo, Nx) and managing shared component libraries AWS services knowledge (S3, CloudFront, Lambda) and understanding of serverless architectures Built or contributed to design systems or open-source component libraries Experience with Playwright, Puppeteer, or Cypress for comprehensive E2E testing Experience building AI agent interfaces or agentic AI workflows What Shelf Offers: B2B contract Company Stock Options Hardware: MacBook Pro Modern technical stack. Develop open-source software Premier AI development environment: GitHub Copilot, Claude Code, OpenAI Codex, TypingMind, v0, MCP Servers, plus credits for experimenting with emerging AI tools Why Shelf GenAI will be at least a $18 Trillion market by 2032 and Shelf is a core infrastructure that enables GenAI to be deployed at scale We are blazing the path for the future of Artificial Intelligence globally. Our Leadership Team has deep AI domain expertise and enterprise SaaS background to execute this plan We love our customers and our customers love us. Ask a Shelf customer why, and they’ll tell you it’s because of our innovative capabilities, rock-solid reliability, they truly enjoy working with our people, but most of all — it’s the improvements they see in their business KPIs. We have raised over $60 million in funding and our investors include; Insight Partners, Tiger Global, Base10, and others We have high velocity growth powered by the most innovative product in our category We now have over 100 employees in multiple U.S. states and European countries, and we have ambitious hiring goals over the next few quarters.

🏢 Summary: Frontend Engineer role focused on building production-grade Next.js SSR applications that power enterprise AI interfaces with real-time LLM streaming, complex state management, and high-load performance. The position involves architecting scalable, accessible, and secure UIs integrated with AI systems and large-scale data services. It requires delivering performant, enterprise-ready frontend solutions for mission-critical AI-driven workflows. 🗂️ Requirements: 5+ years frontend engineering experience, 3+ years commercial experience with React, Production experience with Next.js SSR applications, Advanced TypeScript expertise, Experience with complex state management in large-scale applications, Experience building AI/LLM interfaces with real-time streaming, Proven performance optimization for high-load applications, Experience with enterprise features: i18n, accessibility, security compliance, Strong knowledge of modern CSS and responsive design, Experience integrating REST APIs and WebSockets, Experience with observability and frontend monitoring tools, Experience with AI coding assistants 📃 Skills: React, Next.js, TypeScript, JavaScript, SWR, REST, WebSockets, Tailwind, CSS, Storybook, ReactFlow, Highcharts, Playwright, Datadog, Sentry, Elasticsearch, DynamoDB, PostgreSQL, Aurora, SOC2 🏢 Description: As a Frontend Engineer at Shelf, you’ll craft the interfaces that make enterprise AI accessible and trustworthy. While others are building chatbots, we’re solving the harder problem: how do you build UIs that help users confidently navigate AI-powered systems processing millions of documents, while maintaining enterprise-grade reliability? You won’t just build React components — you’ll architect production-ready Next.js applications that handle high-load scenarios with complex states, real-time AI streaming, and multiple layers of enterprise functionality. Every interface decision you make directly impacts how knowledge workers at the biggest companies in the market interact with their most critical information. This is frontend engineering at its most demanding. You’ll tackle challenges like building real-time streaming interfaces for LLM responses, architecting state management for concurrent AI operations across multiple tenants, creating accessible interfaces for complex knowledge graphs with thousands of nodes, and ensuring blazing fast interactions even with petabytes of searchable content. Your components will bridge everything from enterprise authentication systems to cutting-edge AI models, requiring both sophisticated technical skills and sharp product instincts. We obsess over frontend quality because we’re building the trust layer for AI itself. When your interfaces gracefully handle edge cases, provide clear feedback during AI processing, and remain performant under load, you’re not just meeting UX standards — you’re directly enabling users to trust AI-powered answers and make critical business decisions with confidence. You’ll work on production SSR applications serving thousands of enterprise users, implementing localization for global markets, ensuring accessibility compliance, and maintaining security standards that pass SOC 2 audits. Your code will integrate with our Elasticsearch clusters, DynamoDB tables, and Aurora PostgreSQL databases through the largest park of REST APIs, handling real-time websocket updates for AI streaming and collaborative features. We’re a product company that ships fast without compromising on lasting quality. You’ll work alongside proactive, ever-learning engineers who actively use AI coding assistants (OpenAI Codex, Claude Code) to accelerate development. We build custom MCP servers, implement DSPy pipelines for LLM optimization, and experiment with different AI tools for implementation. In our environment, AI isn’t just what we build — it’s how we build. The best engineers we know are drawn to problems that matter. If you’re excited by the challenge of building interfaces that make the AI revolution actually usable and trustworthy for enterprise users, this role offers the rare combination of technical depth, meaningful impact, and the prestige of solving UX patterns that the industry hasn’t figured out yet. Responsibilities Design and implement production-ready Next.js SSR applications with complex state management, handling high-load scenarios and real-time AI interactions at scale Build interfaces for AI-powered features including streaming LLM responses, semantic search across millions of documents, interactive knowledge graphs, intelligent content recommendations, and AI agentic builders Architect component libraries and maintain our design system in Storybook, ensuring reusability, accessibility, and consistent UX patterns across the platform Develop enterprise-grade functionality including multi-language support, accessibility compliance, cross-browser compatibility, and security implementations that meet SOC 2 standards Create comprehensive technical specifications and component API designs that clearly communicate interface decisions, performance trade-offs, and accessibility considerations Build and optimize data-heavy UIs using React Flow for node-based graphs, Highcharts for analytics visualizations, and custom virtualization for handling large datasets Instrument components for performance monitoring, track Core Web Vitals, implement error boundaries, and build automated visual regression tests with Playwright Take full ownership of the features you build, monitoring their performance in production, optimizing bundle sizes, and ensuring they scale gracefully as user load grows Work with SWR for intelligent data fetching, caching, and revalidation strategies that minimize API calls while keeping UIs responsive and data fresh Integrate with backend services via REST APIs, handle websocket connections for real-time updates, and implement optimistic UI patterns for seamless user experiences Leverage AI coding assistants to accelerate development while maintaining high code quality, and contribute to building internal AI agents that automate frontend workflows Stay current with React ecosystem best practices, Next.js updates, AI UX patterns, and modern frontend architecture—experiment with new approaches and share findings with the team Contribute to our engineering standards and practices through thoughtful code reviews, mentor colleagues on frontend best practices, and actively participate in our culture of continuous learning Requirements Over 5 years of professional frontend engineering experience, including more than 3 years specializing in React and modern JavaScript/TypeScript Production Next.js experience — you’ve built and shipped SSR applications at scale, understand app router patterns, server components, and the trade-offs between SSR, SSG, and CSR Deep TypeScript expertise — you write type-safe code with generics, utility types, and advanced patterns. Complex state management — hands-on experience architecting state solutions for challenging scenarios: real-time collaboration, optimistic updates, multi-tenant data isolation, and large-scale data synchronization Enterprise application development — you’ve built applications with localization (i18n), accessibility, security best practices, and compliance requirements. You understand the complexity beyond “making it work” AI/LLM interface experience — you’ve built interfaces for AI-powered features: streaming token responses, chat UIs, semantic search, or similar real-time AI interactions High-load optimization — proven track record optimizing applications for performance under heavy traffic, large datasets, and concurrent operations. You monitor Core Web Vitals and know how to improve them Modern CSS mastery — strong expertise with Tailwind CSS and/or CSS-in-JS solutions. You can implement pixel-perfect designs while maintaining responsive layouts and dark mode support Write well-structured, testable code with thoughtful component abstractions and clean APIs. You know when to abstract and when to keep it simple Strong problem-solving skills and genuine curiosity — you don’t wait for designs to be perfect but proactively identify UX issues and propose solutions. You’re never satisfied with “good enough” and constantly refine your craft Experience with AI coding assistants (OpenAI Codex, Claude, etc.) and eagerness to push the boundaries of AI-assisted development. Part of this role involves creating AI agents to automate portions of the frontend workflow Familiarity with observability and monitoring tools like Datadog, Sentry, or similar platforms for tracking frontend performance and errors in production Upper-Intermediate or better English skills for technical communication, documentation, and collaborating with distributed teams Present your work effectively both verbally and visually — you can articulate design decisions, create component documentation, and explain technical trade-offs clearly Be a Plus: Experience with React Flow, Highcharts, or other complex data visualization libraries Understanding of Node.js/Python/backend fundamentals — you can read backend code and contribute to API design discussions Experience with SWR, React Query, or similar data fetching libraries Hands-on experience with vector search UIs, RAG interfaces, or semantic search implementations Familiarity with MCP (Model Context Protocol), DSPy, or other cutting-edge AI frameworks Experience with monorepo tools (Lerna, Turborepo, Nx) and managing shared component libraries AWS services knowledge (S3, CloudFront, Lambda) and understanding of serverless architectures Built or contributed to design systems or open-source component libraries Experience with Playwright, Puppeteer, or Cypress for comprehensive E2E testing Experience building AI agent interfaces or agentic AI workflows What Shelf Offers: B2B contract Company Stock Options Hardware: MacBook Pro Modern technical stack. Develop open-source software Premier AI development environment: GitHub Copilot, Claude Code, OpenAI Codex, TypingMind, v0, MCP Servers, plus credits for experimenting with emerging AI tools Why Shelf GenAI will be at least a $18 Trillion market by 2032 and Shelf is a core infrastructure that enables GenAI to be deployed at scale We are blazing the path for the future of Artificial Intelligence globally. Our Leadership Team has deep AI domain expertise and enterprise SaaS background to execute this plan We love our customers and our customers love us. Ask a Shelf customer why, and they’ll tell you it’s because of our innovative capabilities, rock-solid reliability, they truly enjoy working with our people, but most of all — it’s the improvements they see in their business KPIs. We have raised over $60 million in funding and our investors include; Insight Partners, Tiger Global, Base10, and others We have high velocity growth powered by the most innovative product in our category We now have over 100 employees in multiple U.S. states and European countries, and we have ambitious hiring goals over the next few quarters.

🏢 Summary: Senior Backend Engineer responsible for designing, building, and maintaining production-grade backend systems that power AI-driven business automation. The role covers full ownership from system design to deployment, focusing on scalable, reliable distributed systems and cloud infrastructure. This is a Warsaw-based, office role with strong emphasis on technical leadership and AI-supported development workflows. 🗂️ Requirements: Senior-level experience in backend engineering on production systems, Strong Python programming skills, Experience with distributed systems concepts, Experience with cloud platforms (AWS, Azure, or similar), Knowledge of SQL and NoSQL databases, Ability to design, implement, and deliver systems to production, Strong written and spoken communication skills, Regular use of AI tools in development workflows 📃 Skills: Python, AWS, Azure, SQL, NoSQL, DistributedSystems, Concurrency, AsynchronousProcessing, APIs, Cloud, GitHubCopilot, OpenAI, Claude, TypeScript 🏢 Description: About Us Many companies want to use AI agents, but these agents often struggle with real business tasks. We solve this problem by building a platform that helps AI understand business rules, workflows, and processes. This allows AI to make better decisions and provide accurate, reliable, and compliant results. Well-known companies from different industries use our technology to automate up to 85% of customer cases, reduce handling time by 20–25%, and complete tasks that used to take hours in just seconds. We also work with leading technology partners and have been recognized for our innovative approach. Our goal is to help people everywhere get better answers through AI. Job Description We are looking for a Senior Backend Engineer who can take ownership of important systems instead of only completing assigned tasks. You will solve complex problems, design backend solutions, build them, and make sure they run well in production. We want someone with strong technical skills, good communication, and the ability to create simple, reliable, and easy-to-maintain systems. This is a product engineering role with responsibility from system design to production. The position is based in Warsaw and requires office work. Responsibilities Design and develop backend services, APIs, data processing, and background tasks for production systems. Turn unclear business needs into clear technical plans and practical solutions. Maintain services after release by improving reliability, monitoring, performance, and fixing issues. Make good decisions about system architecture, data models, interfaces, and future scaling. Write technical documentation, architecture notes, and diagrams when they help the team. Work closely with product managers, frontend engineers, and platform engineers to deliver complete solutions. Improve development processes using AI tools, automation, and internal workflows. Support the team through code reviews, design reviews, and practical technical leadership. Requirements Strong experience as a senior backend engineer working on production systems. Excellent Python skills and the ability to write clean and maintainable code. Good understanding of distributed systems, including concurrency, failure handling, data consistency, asynchronous processing, and service design. Experience with cloud platforms such as AWS, Azure, or similar services. Knowledge of SQL, NoSQL databases, schema design, and performance optimization. Ability to take a project from an idea through design and implementation to production. Strong written and spoken communication skills with the ability to explain technical topics clearly. Regular use of AI tools in everyday development and interest in improving AI-based workflows. Nice to Have Experience with LLM-based applications, search systems, AI infrastructure, or large data pipelines. Knowledge of TypeScript or the ability to contribute to frontend development when needed. Experience guiding other engineers and influencing technical decisions without being a formal manager. What We Offer B2B contract and company stock options. MacBook Pro for work. Modern technology stack and opportunities to contribute to open-source projects. Access to advanced AI development tools, including GitHub Copilot, Claude Code, OpenAI Codex, TypingMind, and MCP servers. Our Culture and Values Our leadership team has strong experience in AI and knowledge management. We have secured more than $60 million in funding and achieved three years of continuous 3x growth. Our work is based on these values: Quality – We aim for excellent work and high coding standards. Momentum – We take initiative and keep projects moving forward. Accountability – We take responsibility and give honest, respectful feedback. Hard Work – We believe great results come from teamwork and consistent effort. Learning Agility – We stay curious, learn from mistakes, and improve every day. Adapt and Thrive – We accept change and see challenges as opportunities. Win Together – We succeed as one team through honesty, openness, and support for our shared mission.

🏢 Summary: Senior Full Stack Engineer role focused on building and owning end-to-end product features for an AI-driven platform that automates complex business processes. The position involves developing frontend and backend solutions, designing APIs, improving performance and usability, and leveraging AI tools in daily engineering work. The role is office-based in Warsaw and requires strong product thinking and production-level experience. 🗂️ Requirements: Senior-level experience building production web applications, Strong knowledge of React and TypeScript or similar frontend framework, Experience designing and developing backend APIs and application logic, Ability to build and maintain frontend and backend features end-to-end, Experience working with production environments and monitoring released features, Daily use of AI tools for development and problem-solving, Strong understanding of code quality, testing, and long-term ownership 📃 Skills: React, TypeScript, JavaScript, API, REST, Node.js, Python, GitHub, Copilot, Claude, OpenAI, Codex, TypingMind, MCP, AI 🏢 Description: About Us Many companies want to use AI agents, but these agents often have problems with complex business tasks. We help solve this issue. Our platform understands company rules, processes, and workflows, so AI can make better decisions instead of only giving simple answers. This allows businesses to use AI that is accurate, follows company policies, and can be trusted. Well-known companies use our technology to automate up to 85% of customer cases, reduce handling time by 20–25%, and complete tasks that used to take hours in just a few seconds. We work with leading technology partners and have received industry recognition for our innovative approach. Our mission is to give people better answers everywhere. About the Role We are looking for a Senior Full Stack Engineer with strong product thinking. In this role, you will own features from start to finish. You will understand user needs, plan solutions, build frontend and backend functionality, release new features, and improve them based on user feedback. You should feel comfortable working on user interfaces, APIs, and production quality while collaborating with product and design teams. Location: Warsaw (office-based). Responsibilities Build and deliver product features across both frontend and backend. Turn product ideas into practical and effective solutions. Work with user interfaces, business logic, APIs, and data flows. Cooperate closely with product managers and designers, even when requirements are still developing. Improve usability, performance, reliability, and overall user experience. Monitor released features and use production data to make improvements. Use AI tools every day to work faster and improve engineering processes. Maintain high standards for code quality, testing, and long-term ownership. Requirements Strong experience as a senior engineer building production web applications. Good knowledge of React, TypeScript, or a similar modern frontend framework. Experience designing and developing backend APIs and application logic. Strong product mindset with the ability to identify and improve weak user experiences. Good decision-making skills when balancing scope, speed, and technical quality. Clear communication and teamwork across engineering, product, and design. Daily experience using AI tools for development and problem-solving. Nice to Have Experience building AI-powered products such as chat, search, recommendation systems, workflows, or AI agents. Knowledge of Python, Node.js, or both. Experience owning product areas independently. Understanding of performance optimization, accessibility, and high-quality web applications. What We Offer B2B contract and company stock options. MacBook Pro for work. Modern technology stack with opportunities to contribute to open-source projects. Advanced AI development tools, including GitHub Copilot, Claude Code, OpenAI Codex, TypingMind, and MCP Servers. Why Join Us Our leadership team has strong experience in knowledge management and AI. We have raised more than $60 million in funding and achieved three years of continuous 3x growth. Our work is guided by these core values: Quality: We aim for excellent craftsmanship and high standards in everything we build. Momentum: We take initiative and keep projects moving forward. Accountability: We take responsibility, give honest feedback, and support each other. Hard Work: We believe difficult goals require dedication and teamwork. Learning Agility: We stay curious, learn from mistakes, and keep improving. Adapt and Thrive: We accept change and see challenges as opportunities. Win Together: We succeed as a team through honesty, openness, and shared commitment.

🏢 Summary: Senior or Staff Backend Engineer role focused on architecting and scaling AI-native backend systems for a modern accounting platform. The position involves designing distributed services, building high-performance APIs, and establishing engineering standards to support rapid, reliable product delivery. You will work closely with Product, AI, and Operations teams to develop agentic systems and scalable data pipelines. 🗂️ Requirements: 5–10+ years of backend engineering experience, Proven experience designing, building, and operating production backend systems at scale, Strong expertise in API design, Strong expertise in data modelling, Deep understanding of distributed systems trade-offs, Hands-on experience with AWS or GCP in production, Practical experience with CI/CD in high-frequency deployment environments, Experience implementing testing and deployment strategies, Strong knowledge of observability practices, Experience participating in on-call rotations 📃 Skills: TypeScript, Node.js, React, AWS, GCP, Terraform, PostgreSQL, OpenAI, Azure, CI/CD, APIs, DistributedSystems 🏢 Description: ABOUT THE ROLE We're looking for a Senior or Staff Backend Engineer to own and evolve our backend services as we scale. This is a broad, high-impact role — you'll architect new features, build the systems that underpin our core product, and set the engineering standards that shape how the whole team works. The focus is on building a modern, AI-native developer experience. That means working closely with Product, AI, and Operations teams to design agentic systems, distributed data pipelines, and scalable incident response infrastructure — and doing it in a way that lets the team ship with confidence multiple times a day. WHAT YOU'LL WORK ON Architecture and feature design Partner with Product, AI, and Operations teams to architect new features and complex agentic systems. Make clear architectural trade-offs that balance platform, product, and business goals. Backend services and APIs Build and maintain the backend services and APIs that power the core product. Ensure systems are secure, well-tested, and high performance. Distributed systems Design and implement distributed services to orchestrate data pipelines, automate investigations, and enable incident response at scale. Operational excellence Own operational best practices so the team can ship multiple times a day with confidence. Healthy on-call culture and strong observability are part of what you'll build and maintain. Engineering standards Set the bar for writing, communication, and system design across the team. Your influence will shape how a modern AI-native product is built. WHAT WE LOOK FOR 5–10+ years of backend engineering experience A strong track record designing, building, and operating production backend systems at scale. Deep backend fundamentals Expertise in API design, data modelling, and reasoning about distributed systems trade-offs. You understand the nuances, not just the patterns. AWS or GCP hands-on experience Solid understanding of how infrastructure decisions impact application reliability and performance. You've run things in production, not just designed them. CI/CD in practice Practical experience with testing and deployment strategies in high-frequency shipping environments. Observability and on-call maturity A solid grasp of what good observability looks like and how to build healthy on-call practices that don't burn people out. Bonus Experience at an early-stage or scaling startup. Exposure to modern AI and ML systems. Experience shipping product without a dedicated product manager. TECH STACK TypeScript, React, Node.js, AWS, Terraform, PostgreSQL, OpenAI, Azure AI. The team uses GitHub, Slack, Linear, Figma, and Notion day to day. THE TEAM Small, senior, and in-person. The office is in central Wrocław, next to the main train station. The expectation is 4–5 days a week in the office. Relocation support is available for the right candidate. COMPENSATION & BENEFITS Salary $130,000 – $190,000 USD depending on experience, plus competitive equity. Wellness and commute stipend $100 per month. Hardware Premium hardware provided — MacBook Pro and AirPods. Food Daily in-office lunch and dinner. Time off 20 PTO days plus 9 US public holidays. Relocation Support available for candidates relocating to Wrocław.

🏢 Summary: Senior or Staff Backend Engineer role focused on architecting and scaling AI-native backend services for a modern accounting platform. The position involves designing distributed systems, building secure and high-performance APIs, and establishing engineering standards to support rapid, reliable product delivery. You will work closely with Product, AI, and Operations teams to build scalable data pipelines and incident response infrastructure. 🗂️ Requirements: 5–10+ years of backend engineering experience, Proven experience designing and operating production backend systems at scale, Strong expertise in API design and data modelling, Deep understanding of distributed systems and architectural trade-offs, Hands-on experience with AWS or GCP in production environments, Practical experience with CI/CD pipelines and automated testing, Experience building and maintaining observability and on-call practices 📃 Skills: TypeScript, Node.js, React, AWS, GCP, Terraform, PostgreSQL, OpenAI, Azure, CI/CD, APIs, DistributedSystems, DataModelling, Observability 🏢 Description: ABOUT THE COMPANY We're an applied AI company building an AI-native alternative to legacy accounting software — a market worth tens of billions in annual recurring revenue. Our mission is to help entrepreneurs focus on what matters in their business and life, and to help their accountants become more strategic. We've raised $20M from a group of top-tier investors and have grown ARR 60% month-on-month since our public launch. We now serve thousands of businesses and are expanding our product to serve accountants directly — creating a two-sided platform where both business owners and their accountants use and recommend us. We're at an early but proven stage, moving fast, and building a world-class engineering team in Wrocław to match our ambition. ABOUT THE ROLE We're looking for a Senior or Staff Backend Engineer to own and evolve our backend services as we scale. This is a broad, high-impact role — you'll architect new features, build the systems that underpin our core product, and set the engineering standards that shape how the whole team works. The focus is on building a modern, AI-native developer experience. That means working closely with Product, AI, and Operations teams to design agentic systems, distributed data pipelines, and scalable incident response infrastructure — and doing it in a way that lets the team ship with confidence multiple times a day. WHAT YOU'LL WORK ON Architecture and feature design Partner with Product, AI, and Operations teams to architect new features and complex agentic systems. Make clear architectural trade-offs that balance platform, product, and business goals. Backend services and APIs Build and maintain the backend services and APIs that power the core product. Ensure systems are secure, well-tested, and high performance. Distributed systems Design and implement distributed services to orchestrate data pipelines, automate investigations, and enable incident response at scale. Operational excellence Own operational best practices so the team can ship multiple times a day with confidence. Healthy on-call culture and strong observability are part of what you'll build and maintain. Engineering standards Set the bar for writing, communication, and system design across the team. Your influence will shape how a modern AI-native product is built. WHAT WE LOOK FOR 5–10+ years of backend engineering experience A strong track record designing, building, and operating production backend systems at scale. Deep backend fundamentals Expertise in API design, data modelling, and reasoning about distributed systems trade-offs. You understand the nuances, not just the patterns. AWS or GCP hands-on experience Solid understanding of how infrastructure decisions impact application reliability and performance. You've run things in production, not just designed them. CI/CD in practice Practical experience with testing and deployment strategies in high-frequency shipping environments. Observability and on-call maturity A solid grasp of what good observability looks like and how to build healthy on-call practices that don't burn people out. Bonus Experience at an early-stage or scaling startup. Exposure to modern AI and ML systems. Experience shipping product without a dedicated product manager. TECH STACK TypeScript, React, Node.js, AWS, Terraform, PostgreSQL, OpenAI, Azure AI. The team uses GitHub, Slack, Linear, Figma, and Notion day to day. THE TEAM Small, senior, and in-person. The office is in central Wrocław, next to the main train station. The expectation is 4–5 days a week in the office — this is a deliberate choice, not a compromise. Relocation support is available for the right candidate. COMPENSATION & BENEFITS Salary $130,000 – $190,000 USD depending on experience, plus competitive equity. Wellness and commute stipend $100 per month. Hardware Premium hardware provided — MacBook Pro and AirPods. Food Daily in-office lunch and dinner. Time off 20 PTO days plus 9 US public holidays. Relocation Support available for candidates relocating to Wrocław.

🏢 Summary: Mid Full Stack Engineer role focused on building and improving AI-powered enterprise products across frontend and backend systems. The position involves developing web applications, APIs, and production features using modern technologies while collaborating closely with cross-functional teams. Candidates will work with AI development tools and contribute to scalable, high-quality software in a fast-growing environment. 🗂️ Requirements: 2–5 years of experience building production web applications, Knowledge of React, Knowledge of TypeScript or another modern frontend framework, Experience building backend services, Experience building REST APIs, Familiarity with testing and version control, Understanding of web application architecture, Understanding of client-server communication, Problem-solving skills, Attention to code quality, Strong communication skills, Experience using AI development tools, Willingness to collaborate across engineering, product, and design teams 📃 Skills: React, TypeScript, REST, Git, GitHub, Copilot, Claude, ChatGPT, Python, Node.js, AWS, GCP, Azure, Docker, CI/CD 🏢 Description: About Us Many companies want to use AI agents, but these agents often struggle with complex business tasks. We solve this problem by building a platform that understands company knowledge, policies, processes, and workflows, enabling AI to make reliable decisions instead of simply generating answers. Our technology helps businesses automate up to 85% of customer cases, reduce handling time by 20–25%, and complete tasks that previously took hours in just a few seconds. Our mission is simple: to give people better answers everywhere. About the Role We are looking for a Mid Full Stack Engineer who enjoys building products and solving real user problems. In this role, you'll work across both the frontend and backend, collaborating closely with engineers, product managers, and designers to deliver new features and improve existing ones. You'll have the opportunity to work with modern AI technologies, contribute to production systems, and grow your technical skills in a fast-moving environment. If you enjoy learning, shipping high-quality software, and working on products used by enterprise customers, we'd love to hear from you. Responsibilities - Build and maintain product features across both frontend and backend. - Develop user interfaces using modern frontend technologies. - Build and extend backend APIs and business logic. - Collaborate with engineers, product managers, and designers to implement new functionality. - Improve application performance, reliability, and usability. - Write clean, maintainable, and well-tested code. - Participate in code reviews and engineering discussions. - Help monitor production systems and improve features based on user feedback and product data. - Use AI development tools to improve productivity and software development workflows. Requirements - 2–5 years of experience building production web applications. - Good knowledge of React, TypeScript, or another modern frontend framework. - Experience building backend services and REST APIs. - Familiarity with modern software engineering practices, testing, and version control. - Understanding of web application architecture and client-server communication. - Good problem-solving skills and attention to code quality. - Strong communication skills and willingness to collaborate across engineering, product, and design teams. - Experience using AI tools such as GitHub Copilot, Claude Code, ChatGPT, or similar in day-to-day development. - Curiosity, ownership of your work, and a desire to continuously learn. Nice to Have - Experience with Python, Node.js, or both. - Experience working on AI-powered products or LLM integrations. - Familiarity with cloud platforms (AWS, GCP, or Azure). - Knowledge of Docker, CI/CD, or modern deployment workflows. - Understanding of performance optimization and accessibility best practices. What We Offer - B2B contract. - Company stock options. - MacBook Pro for work. - Modern technology stack with opportunities to contribute to open-source projects. - Access to advanced AI development tools, including GitHub Copilot, Claude Code, OpenAI Codex, TypingMind, and MCP Servers. - The opportunity to work on real AI products used by enterprise customers. - A collaborative engineering culture focused on learning, ownership, and continuous improvement. - The chance to grow your career alongside experienced engineers in a fast-growing AI company. Why Join Us Our leadership team brings deep experience in AI and knowledge management. We've raised over $60 million in funding and achieved three consecutive years of 3× growth. We believe great products are built by great teams, and our culture is shaped by these values: - Quality - We care about craftsmanship and building software that lasts. - Momentum - We move quickly, iterate often, and continuously improve. - Accountability - We take responsibility for our work, communicate openly, and support one another. - Hard Work - We believe ambitious goals require dedication and teamwork. - Learning Agility - We stay curious, embrace feedback, and continuously develop our skills. - Adapt and Thrive - We welcome change and see challenges as opportunities to improve. - Win Together - We succeed by collaborating, sharing knowledge, and helping each other grow.