Mid Full-Stack Engineer (React) — AgentX

🏢 Summary: Senior AI-native full-stack engineer role focused on building and owning production-grade agentic systems end-to-end, from architecture to deployment and on-call. The position involves developing multi-agent workflows, RAG pipelines, and AI infrastructure, as well as delivering client-facing B2B solutions on top of an internal agent platform. Strong ownership, hands-on LLM production experience, and full-stack execution across frontend, backend, and cloud infrastructure are required. 🗂️ Requirements: 5+ years of production software engineering experience, 1-2+ years building and operating LLM systems in production, Experience deploying agentic systems with real users, Strong full-stack development experience, Hands-on experience with LLM APIs, RAG, prompt engineering, Experience with at least one agentic framework or custom orchestration, Ability to design, ship, and maintain systems end-to-end, Experience with cloud infrastructure and production deployments, Strong written English 📃 Skills: TypeScript, React, Node.js, Python, PostgreSQL, AWS, Anthropic, OpenAI, LangGraph, CrewAI, RAG, LLM, APIs, SQL, VectorDB 🏢 Description: Who we are AgentX is a platform for building and running production AI agents — and a team that ships real systems on top of it for clients who need more than a demo. The platform is the infrastructure: orchestration, memory, tools, evals, deployment — the layer that makes agentic systems actually work in production, not just in a notebook. On top of it, we build end-to-end solutions for our clients. One of the systems running on AgentX today is KsięgoBoty — a multi-agent product used daily by hundreds of Polish accounting firms. Paying customers, production load, real consequences when something breaks. We've also done to ourselves what we build for others: restructured how we work around AI tools, agent-first architectures, and a delivery model that doesn't need a Jira layer between thinking and shipping. This isn't theory — it's how we operate every day. Who we're looking for A senior engineer who owns outcomes, not tasks. This isn't a role for someone who's shipped "an LLM demo at a hackathon." We need someone who has already put agentic systems into production — with real users, real edge cases, real 2am Slack messages when something goes sideways. If you need a PM to translate the problem, a Jira board with three rounds of grooming, and acceptance criteria to tell you what "done" means — this isn't for you, and that's fine. If instead you read a Slack message like "accountants are losing 2 hours a day reconciling this" and your brain immediately jumps to "okay, what does the user actually need, what's the simplest thing that works, and how do we ship it" — keep reading. You'll own problems end-to-end. Frontend, backend, the agent layer, the deploy, the follow-up when a customer hits something weird. You decide what to build, you build it, you ship it, you watch what happens. And you get that this actually matters. On the other end of every feature there's an accountant closing books at 9pm, a firm owner trying to keep their business running. It's not just code. What "AI-native" actually means here Not "I've used ChatGPT." We mean: Claude Code / Cursor / Codex is your IDE , not a plugin you switch on when you feel like it. You know when "accept all" is safe and when it absolutely isn't. You have strong opinions on agent orchestration — when to reach for LangGraph/CrewAI/Agno vs. when to write 50 lines of plain Python that work better. You understand production reality of LLM systems — guardrails, evals, observability, retry logic, cost control, what to do when a model is non-deterministic in a way that breaks your contract with the user. You can tell when a model is the wrong tool and reach for code instead. For you, AI is a tool — not the point. What you'll actually own Agentic systems in production — multi-step workflows, RAG pipelines, agent orchestration. From architecture decision to deployment to the 3am on-call when something drifts. The AgentX platform itself — the primitives, the orchestration layer, the evals, the deployment story. You're building the thing that makes every client engagement faster and more reliable than the last. Full-stack client solutions on top of AgentX — TypeScript/React on the frontend, Python on the backend, integrated with LLM providers (Anthropic, OpenAI, others as they come). Infrastructure that holds up — Postgres, AWS, vector stores, ingestion pipelines, the unsexy layer that makes everything else possible. Quality standards for AI systems — you help us define what "good" looks like. Evals, guardrails, failure modes. Because "mostly right but wrong in scary ways" is not a feature. Our stack TypeScript, React, Node.js, Python, PostgreSQL, AWS, Anthropic + OpenAI APIs, agentic frameworks. You don't need every box ticked — you need to be the kind of specialist who picks up unfamiliar pieces quickly and confidently. What we expect (must-haves) 5+ years shipping production software , at least 1-2 of them with real LLM systems in production — not side projects, not demos Strong full-stack background — you're comfortable owning from frontend to infra, even if your center of gravity is one side AI-native coding workflow — Claude Code, Cursor, Codex, whatever — as your daily driver Hands-on with LLM APIs, RAG, prompt engineering, and at least one agentic framework (or you've built your own orchestration and have opinions on why) Strong written English — you'll communicate with clients, partners, and async teammates Ability to run a project from discovery to delivery with minimal supervision — we'll align on outcomes, you'll figure out how Nice-to-have Experience building B2B SaaS for non-technical users (SMBs, professional services) Voice agents, real-time systems (LiveKit or similar) Accounting / fintech / regulated domain exposure How we work Fast pace, but Monday to Friday. Weekends are yours. We don't do crunch, we don't do fake urgency, we don't do meetings that could've been a message. We'd rather ship steadily for years than sprint for six months and lose you. Direct line to the founder. Direct line to clients. No process layer between you and the work. Small team, real decisions, real ownership. The honest pitch Real ownership of real product areas — not a seat on a feature factory Frontier work — you're building both the platform that makes production agents work and the client systems running on top of it Compensation that reflects seniority — 14 000 – 25 000 PLN netto + VAT (B2B), with room above for someone exceptional Fully paid AI stack — Claude Max, Cursor, whatever you need to work at full speed Remote-first , flexible hours, Poland-based No filler meetings, no Jira bloat — we measure shipped systems in production, not hours logged Push back on the founder when he's wrong. He will be, regularly. How the process works 1. You send us stuff recruitment@agentx.so Your CV — yes, we read them One thing you built end-to-end you're proud of — and what you'd change about it today One AI product (yours or someone else's) you think is genuinely good, and why Your take: a client says our agent is "mostly right but wrong in ways that scare them." What do you do first? 2. We reply within 2-3 days — either "let's talk" or "not this time, here's why." No black hole. 3. We meet — 30-45 min call with the founder. We talk about your work, you ask us hard questions. If the chemistry isn't there, no hard feelings. 4. Problem-solving session (top 2-3 candidates) — we give you a real problem we're working on. You come back with how you'd approach it: your thinking, your trade-offs, your questions. We're not watching over your shoulder. We want to see how you think. 5. Decision within 2-3 days. If yes — you start when you're ready. Tomorrow, next week, after notice period. Your call.

🏢 Summary: Mid Frontend React Developer role focused on building AI-powered enterprise web applications using React, Next.js, and TypeScript. The position involves developing scalable user interfaces, integrating backend APIs, and improving performance and usability in collaboration with cross-functional teams. The offer includes access to modern AI development tools, stock options, and work on production AI products used by enterprise customers. 🗂️ Requirements: 2–5 years of frontend development experience, React, JavaScript, TypeScript, Next.js or modern React framework, REST APIs, Asynchronous data fetching, Modern CSS solutions, Responsive design, Cross-browser compatibility, Reusable frontend code, Git, Modern development workflows, AI coding tools, English B2+ 📃 Skills: React, Next.js, TypeScript, JavaScript, REST, Tailwind, CSS, Git, Copilot, ChatGPT, Claude, SWR, ReactQuery, Node.js, Python, Playwright, Cypress, AWS, Highcharts 🏢 Description: About Us Many companies want to use AI agents, but these tools often struggle with real business tasks. We build a platform that helps AI understand company knowledge, workflows, and processes, enabling it to provide accurate and reliable answers. Our technology is trusted by large international companies and integrates with leading AI and cloud platforms. Our mission is to help people find better answers and make better decisions with AI. About the Role We are looking for a Mid Frontend React Developer to help build modern web applications that make enterprise AI intuitive and reliable. You'll work closely with experienced frontend engineers, designers, backend developers, and product managers to create fast, responsive, and scalable user experiences. You'll contribute to new features, improve existing functionality, and gain hands-on experience building AI-powered products used by enterprise customers. What You Will Do - Build and maintain modern web applications using React, Next.js, and TypeScript. - Develop user interfaces for AI-powered features such as chat, search, and knowledge management. - Create reusable UI components and contribute to our design system. - Integrate frontend applications with backend APIs and real-time data. - Improve application performance, responsiveness, and user experience. - Write clean, maintainable, and well-tested code. - Participate in code reviews and collaborate with engineers, designers, and product managers. - Use AI development tools to improve productivity and software quality. - Learn from production feedback and continuously improve existing features. Requirements - 2–5 years of experience building modern frontend applications. - Good knowledge of React, JavaScript, and TypeScript. - Experience with Next.js or another modern React framework. - Experience working with REST APIs and asynchronous data fetching. - Familiarity with modern CSS solutions such as Tailwind CSS, CSS Modules, or CSS-in-JS. - Understanding of responsive design and cross-browser compatibility. - Experience writing maintainable, reusable frontend code. - Familiarity with Git and modern development workflows. - Experience using AI coding tools such as GitHub Copilot, Claude Code, ChatGPT, or similar. - English at B2 level or higher. Nice to Have - Experience with React Flow, Highcharts, or similar visualization libraries. - Familiarity with SWR, React Query, or similar data-fetching libraries. - Basic knowledge of Node.js or Python. - Experience working with AI-powered applications, chat interfaces, or search experiences. - Familiarity with Playwright, Cypress, or other frontend testing frameworks. - Basic understanding of accessibility and Core Web Vitals. - Experience with AWS or other cloud platforms. What We Offer - 18,000–23,000 PLN B2B (depending on experience). - Company stock options. - MacBook Pro. - Modern technology stack. - Opportunity to contribute to open-source projects. - Access to advanced AI development tools, including GitHub Copilot, Claude Code, OpenAI Codex, TypingMind, v0, MCP Servers, and credits for testing new AI technologies. - The opportunity to work on production AI products used by enterprise customers. - A collaborative engineering culture focused on learning, mentorship, and continuous improvement. Our Values - Quality - We build software with care and attention to detail. - Momentum - We move quickly, learn continuously, and improve through iteration. - Accountability - We take ownership of our work and communicate openly. - Hard Work - We solve challenging problems together and support one another. - Learning - We stay curious, embrace feedback, and continuously grow. - Adaptability - We welcome change and see new challenges as opportunities. - Teamwork - We collaborate, share knowledge, and celebrate success together.

🏢 Summary: Frontend Engineer role focused on building and owning the UI layer of production-ready AI products for B2B clients using TypeScript and React. The position involves developing performant, maintainable interfaces, integrating REST APIs, and handling real-time data flows in close collaboration with backend engineers. This is a hands-on role working on client-facing AI systems where usability and reliability are critical. 🗂️ Requirements: 3–5 years of experience building production frontend applications, Strong experience with TypeScript and React, Experience integrating REST APIs, Experience handling asynchronous UI states, Ability to manage authentication, loading, and streaming states, Experience with SSE or WebSockets, Ability to read and debug Python and FastAPI code 📃 Skills: TypeScript, React, Vite, REST, SSE, WebSockets, Python, FastAPI, Tailwind, shadcn 🏢 Description: About Agentica Agentica is an AI automation startup that designs and deploys custom AI products and agents for B2B clients worldwide. The company builds production-ready AI systems that automate and replace manual business processes across helpdesks, internal tools, e-commerce, production, and other high-friction areas. Its team delivers practical agentic AI solutions for clients ranging from cybersecurity software distributors to global Web3 companies. The Role You’ll own the frontend layer of AI products and client projects, working mainly with TypeScript and React. This is hands-on work on production systems where usability, performance, and reliability matter. You’ll work closely with the tech team and be responsible for shipping clean, maintainable UI code ready for client use. What You’ll Do Build and maintain frontend applications using TypeScript, React, and Vite. Collaborate with backend engineers to integrate REST APIs and manage async data flows. Prototype new interfaces with clients in early stages. Implement clean, extensible component architectures. Handle auth states, loading states, and streaming data (SSE / WebSockets). Read and debug Python / FastAPI backends when needed. Guide coding agents while ensuring code quality. What We’re Looking For Clear communication and strong ownership. AI-first mindset and ability to learn quickly. 3–5 years building production frontend applications. Strong TypeScript and React experience. Experience integrating APIs and handling async UI states. Comfortable reading Python / FastAPI code. Nice to Have Tailwind CSS or component libraries (e.g., shadcn/ui). B2B SaaS or enterprise product experience. What We Offer Attractive salary PLN 12,000–20,000 depending on experience. High-ownership projects with real technical depth and steep learning curves. Early-stage leverage: join while the company is scaling fast and shape how it grows. Fully remote or hybrid from our office in central Warsaw. Flexible working hours built around output, not presence. A senior, technically sharp team with hands-on AI and software delivery experience. Apply now and build leading AI products. Join a team that cares about quality, ownership, and real client impact.

🏢 Summary: Backend Engineer role focused on building and scaling the core architecture behind AI Agents, including reasoning layers, RAG systems, and high-volume conversational infrastructure. The position involves designing agentic orchestration, modernizing legacy systems, and integrating AI capabilities into scalable microservices running in production. You will work hands-on with LLM integrations, vector databases, and cloud-native infrastructure to support millions of daily conversations. 🗂️ Requirements: 6+ years backend development experience, Strong hands-on expertise in Node.js, Strong hands-on expertise in TypeScript, Experience with async programming, queues, and streams, Experience with real-time communication (WebSockets, service-to-service messaging), Commercial experience implementing RAG and Agentic systems in production, Experience with Function Calling and LLM integrations, Deep understanding of context management and multi-turn conversations, Experience with SQL databases (PostgreSQL), Experience with NoSQL databases (Elasticsearch), Experience with Vector Databases and embeddings, Experience with Google Cloud Platform, Experience with Kubernetes, Ability to design and maintain RESTful APIs, Experience working with microservices and scalable systems 📃 Skills: Node.js, TypeScript, PostgreSQL, Redis, Elasticsearch, Pinecone, pgvector, GCP, Kubernetes, Docker, LangGraph, LLMs, RAG, MCP, PubSub, WebSockets, SSE, Webhooks, Prometheus, Grafana, Vitest, Supertest, Playwright, Go, ETL, Microservices, Concurrency, Async, Streams, Queues, GitHubActions 🏢 Description: About your team You’ll join AI Engines – the team building the backend “brain” of AI Agents in Text App. These aren’t your average scripted bots. Our AI Agents understand context, communicate naturally, and take meaningful actions: from digging through the Knowledge Hub to answer customer queries, to guiding human agents, or triggering automations in third-party tools via Copilot. To make this happen, we need to design highly scalable backend systems capable of handling millions of conversations daily. We build the APIs, develop the reasoning layers, and continuously push the boundaries of what our agents can actually do. You will be responsible for: Hands-on building, scaling, and maintaining the core backend architecture (Vector Database, AI Engines, Knowledge Hub, etc.). Designing and implementing an Agentic reasoning and orchestration layer using Skills and tool calling (a core building block of our architecture). Modernizing the core by taking full ownership of migrating legacy implementations into our modern, highly scalable AI ecosystem. Collaborating with our AI researchers to experiment with, validate, and confidently push new AI features straight to production. Mastering Context Engineering & R&D by moving way beyond basic prompt engineering. You'll be experimenting with and optimizing how our agents communicate with LLMs (taking full ownership of multi-turn conversations, tool calling, advanced RAG integrations, system prompt design, and history management). Designing RESTful APIs and service integrations for AI and data-heavy use cases, while migrating legacy implementations to a modern ecosystem. Integrating AI Agents with MCP servers, shaping how they interact with external ecosystems. Setting the standard by taking an active part in architecture discussions, code reviews, and technical decision-making, while bringing an extreme ownership and "fast flagging" mindset to the team. You may be a good fit for this role if you: Have 6+ years of experience in backend development, with strong, recent, hands-on expertise in Node.js and TypeScript in recent projects . We need someone who is fluent in async programming, queues, and streams, and can jump into our codebase on Day 1. Have hands-on experience with real-time communication (WebSockets, async service-to-service messaging). Have proven commercial experience building AI-driven features . You don't just know the concepts—you’ve actively implemented RAG, Function Calling, and Agentic systems in production. A deep understanding of Context Engineering. You know that it’s no longer just about "writing good prompts." You have proven experience managing context windows, multi-turn conversation history, and tool calling within Agentic or RAG ecosystems. Have a solid grasp of database ecosystems, including SQL (Postgres) , NoSQL (Elasticsearch) , and Vector Databases (e.g., Pinecone, pgvector), along with the mechanics of embeddings. Know how to run and scale services on Google Cloud Platform and Kubernetes. Enjoy solving complex technical challenges in microservices, concurrency, and performance optimization. Bonus if you also: Experience with Go (Golang) is a strong plus. Have experience building Data Pipelines or ETL processes. Previous work on SaaS products, low-code/no-code platforms, or workflow automation. Our Tech Stack: (Let’s be transparent: while we value curiosity and a growth mindset, solid hands-on experience with Node.js and TypeScript is a strict requirement for this role. We are happy to give you time to learn our specific AI frameworks and databases on the go, as long as your core backend skills are top-notch.) Core (Must-have) : Node.js, TypeScript Databases : PostgreSQL, Redis, ElasticSearch Scalability & communication : PubSub, Webhooks, SSE AI-related : LLMs, LangGraph, Function Calling, Context Compression, MCP (Model Context Protocol) Infrastructure & deployment : Docker, GitHub Actions, Prometheus, Grafana Testing & reliability : Vitest, Supertest, Playwright How we work We’re a hybrid team – remote when it makes sense, onsite when it matters most. Once per quarter, your whole team spends 5 working days together at our Wrocław office – a time for focused execution, unblocking work, and driving key outcomes. Our office is open year-round – drop by anytime. Contract: B2B (self-employed). You’ll need a registered business in selected EU countries — either already set up or possible to register in your country . Please apply only if this works for you.

🏢 Summary: Senior Backend Engineer role focused on building and scaling the core AI backend powering advanced AI Agents, including reasoning layers, RAG systems, and real-time integrations. The position involves designing scalable architectures, implementing agentic orchestration with tool calling, and modernizing legacy systems into a high-performance AI ecosystem. You will work hands-on with Node.js and TypeScript to deliver production-ready AI-driven features handling millions of conversations. 🗂️ Requirements: 6+ years backend development experience, Strong hands-on Node.js experience, Strong hands-on TypeScript experience, Fluency in async programming, queues, streams, Experience with WebSockets and async messaging, Commercial experience implementing RAG systems, Experience with Function Calling in production, Experience building Agentic systems, Context window and multi-turn conversation management, Experience with SQL and NoSQL databases, Experience with Vector Databases and embeddings, Experience with GCP and Kubernetes, Experience with microservices architecture, Experience with Docker-based deployments 📃 Skills: Node.js, TypeScript, PostgreSQL, Redis, Elasticsearch, Pinecone, pgvector, GCP, Kubernetes, Docker, PubSub, WebSockets, SSE, LLMs, LangGraph, RAG, MCP, GitHub, Prometheus, Grafana, Vitest, Supertest, Playwright, Go 🏢 Description: About your team You’ll join AI Engines – the team building the backend “brain” of AI Agents in Text App. These aren’t your average scripted bots. Our AI Agents understand context, communicate naturally, and take meaningful actions: from digging through the Knowledge Hub to answer customer queries, to guiding human agents, or triggering automations in third-party tools via Copilot. To make this happen, we need to design highly scalable backend systems capable of handling millions of conversations daily. We build the APIs, develop the reasoning layers, and continuously push the boundaries of what our agents can actually do. You will be responsible for: Hands-on building, scaling, and maintaining the core backend architecture (Vector Database, AI Engines, Knowledge Hub, etc.). Designing and implementing an Agentic reasoning and orchestration layer using Skills and tool calling (a core building block of our architecture). Modernizing the core by taking full ownership of migrating legacy implementations into our modern, highly scalable AI ecosystem. Collaborating with our AI researchers to experiment with, validate, and confidently push new AI features straight to production. Mastering Context Engineering & R&D by moving way beyond basic prompt engineering. You'll be experimenting with and optimizing how our agents communicate with LLMs (taking full ownership of multi-turn conversations, tool calling, advanced RAG integrations, system prompt design, and history management). Designing RESTful APIs and service integrations for AI and data-heavy use cases, while migrating legacy implementations to a modern ecosystem. Integrating AI Agents with MCP servers, shaping how they interact with external ecosystems. Setting the standard by taking an active part in architecture discussions, code reviews, and technical decision-making, while bringing an extreme ownership and "fast flagging" mindset to the team. You may be a good fit for this role if you: Have 6+ years of experience in backend development, with strong, recent, hands-on expertise in Node.js and TypeScript in recent projects . We need someone who is fluent in async programming, queues, and streams, and can jump into our codebase on Day 1. Have hands-on experience with real-time communication (WebSockets, async service-to-service messaging). Have proven commercial experience building AI-driven features . You don't just know the concepts—you’ve actively implemented RAG, Function Calling, and Agentic systems in production. A deep understanding of Context Engineering. You know that it’s no longer just about "writing good prompts." You have proven experience managing context windows, multi-turn conversation history, and tool calling within Agentic or RAG ecosystems. Have a solid grasp of database ecosystems, including SQL (Postgres) , NoSQL (Elasticsearch) , and Vector Databases (e.g., Pinecone, pgvector), along with the mechanics of embeddings. Know how to run and scale services on Google Cloud Platform and Kubernetes. Enjoy solving complex technical challenges in microservices, concurrency, and performance optimization. Bonus if you also: Experience with Go (Golang) is a strong plus. Have experience building Data Pipelines or ETL processes. Previous work on SaaS products, low-code/no-code platforms, or workflow automation. Our Tech Stack: (Let’s be transparent: while we value curiosity and a growth mindset, solid hands-on experience with Node.js and TypeScript is a strict requirement for this role. We are happy to give you time to learn our specific AI frameworks and databases on the go, as long as your core backend skills are top-notch.) Core (Must-have) : Node.js, TypeScript Databases : PostgreSQL, Redis, ElasticSearch Scalability & communication : PubSub, Webhooks, SSE AI-related : LLMs, LangGraph, Function Calling, Context Compression, MCP (Model Context Protocol) Infrastructure & deployment : Docker, GitHub Actions, Prometheus, Grafana Testing & reliability : Vitest, Supertest, Playwright How we work We’re a hybrid team – remote when it makes sense, onsite when it matters most. Once per quarter, your whole team spends 5 working days together at our Wrocław office – a time for focused execution, unblocking work, and driving key outcomes. Our office is open year-round – drop by anytime. Contract: B2B (self-employed). You’ll need a registered business in selected EU countries — either already set up or possible to register in your country . Please apply only if this works for you.

🏢 Summary: Early-stage startup seeks a Full Stack Engineer to build the MVP of an agentic AI platform for security compliance using React and FastAPI. You will lead application code development in a small team, contributing to both frontend and backend as well as the foundation of an agent orchestration mechanism. The role offers strong ownership and direct impact on the product architecture. 🗂️ Requirements: Strong experience with React, Strong experience with Python backend development, Ability to work across full stack, Availability for hybrid work in Gdańsk 📃 Skills: React, Python, FastAPI, Django, AWS, Docker, GitHub, CICD, LangChain, PydanticAI, APIs 🏢 Description: We're a funded, early-stage startup building an agentic AI platform for security compliance. The product is new, we're opening an R&D centre in Gdańsk and you'd be one of the first engineers on it, with real input into how it's built. We keep meetings and busywork to minimum to build a culture focused on the needs of developers. The role: You will be part of a 4 people development team focused on the development of the MVP for our main product. React on the frontend, FastAPI on the backend. You will lead the application code, working alongside experienced infrastructure engineer and junior AI engineers. You will also engage in building the foundation of a agent orchestration mechanism. Must Have: Strong experience with React Strong experience with Python backend development FastAPI or Django is a huge plus Comfortable owning features across the full stack Availability for hybrid work in Gdańsk Great to have: Experience with any agentic framework such as Pydantic AI or LangChain AWS Docker GitHub Actions / CI/CD What will happen next? We would like to know you better, so we will invite you for a short call Next, you'll be invited to an interview to discuss your previous projects, skills and where you want to develop Why join: It's a new product, so you're building rather than maintaining. You get real ownership and the chance to work on genuinely new AI, in a calm, focused environment. If you've got the must-haves and the problem interests you, get in touch — you don't need to tick every box.

🏢 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.

🏢 Summary: Frontend Engineer role focused on building enterprise AI applications using Next.js, React, and TypeScript in a fully on-site Warsaw office environment. The position involves developing real-time AI interfaces, managing complex frontend state, improving performance and accessibility, and contributing to technical decisions. Candidates will work with modern AI development tools and enterprise-scale frontend systems. 🗂️ Requirements: 3–5 years of frontend engineering experience, Strong knowledge of React, Strong knowledge of TypeScript, Strong knowledge of Next.js, Experience building production Next.js applications, Understanding of SSR, SSG, and CSR, Experience with complex state management, Experience with real-time updates and optimistic UI, Experience building AI or LLM-based interfaces, Understanding of frontend performance and Core Web Vitals, Knowledge of accessibility and localization, Security-focused development approach, Experience using AI coding assistants, Good communication skills, Ability to work fully on-site in Warsaw 📃 Skills: React, TypeScript, Next.js, SSR, SSG, CSR, AI, LLM, CoreWebVitals, Localization, Accessibility, Security, GitHubCopilot, OpenAI, Claude, ReactFlow, Highcharts, RAG, MCP, DSPy, Node.js, Python 🏢 Description: Please note: This role requires working from our office in Warsaw city centre 5 days a week . This is a fully on-site position , and remote or hybrid work is not available . About us We believe that businesses are moving toward AI-powered work, and we are building a platform for this future. Many AI agents cannot handle complex business tasks. We created a platform that organizes company policies, workflows, and business knowledge into one AI data model. This helps AI agents make accurate decisions and deliver reliable results at scale. We already work with well-known enterprise customers such as Glovo, Nespresso, and HelloFresh. Our platform supports thousands of users and processes real production data. Customers trust us with important business knowledge because we provide a secure and reliable solution with SOC2, HIPAA-ready security practices, and strong integrations. Job description We are looking for a frontend engineer with several years of experience who wants to build user interfaces for enterprise AI products. You will help create applications that allow users to work with AI systems in a simple and reliable way. You will build production applications using Next.js, work with complex application state, real-time AI features, and modern frontend technologies. Over time, you will also take part in important technical decisions. The position is based in Warsaw and requires working from the office. Responsibilities Build and deliver production Next.js applications with complex state management and real-time AI features. Create user interfaces for AI-powered tools, including streaming AI responses, semantic search, knowledge graphs, and AI agents. Help improve our component library and design system to keep the UI consistent, reusable, and accessible. Develop enterprise features such as localization, accessibility, browser compatibility, and security. Monitor applications after release, improve performance, reduce bundle size, and track Core Web Vitals. Use AI tools every day to improve development speed and internal frontend workflows. Maintain high code quality through testing and code reviews. Requirements Around 3–5 years of experience as a frontend engineer. Strong knowledge of React, TypeScript, and Next.js. Experience building production Next.js applications and understanding the differences between SSR, SSG, and CSR. Good experience with state management, including real-time updates, optimistic UI, and multi-tenant applications. Experience building AI or LLM-based interfaces such as chat applications, streaming responses, or semantic search. Good understanding of frontend performance, Core Web Vitals, and user experience. A security-focused approach and knowledge of accessibility and localization. Experience using AI coding assistants as part of your daily development work. Good communication skills and the ability to explain technical decisions clearly. Nice to have Experience with React Flow, Highcharts, or other data visualization libraries. Experience building vector search, RAG, or semantic search interfaces. Knowledge of MCP, DSPy, or other modern AI frameworks. Basic understanding of Node.js or Python backend development. Contributions to design systems or open-source UI libraries. What we offer B2B contract and company stock options. MacBook Pro. Modern technology stack and the opportunity to contribute to open-source projects. An AI-focused development environment with tools such as Claude Code, OpenAI Codex, and GitHub Copilot. Our values Our leadership team has strong experience in AI, knowledge management, and enterprise SaaS. We have received more than $60 million in funding and have been recognized by Gartner as a Cool Vendor. Our work is guided by these values: Quality – We care about excellent work and high standards in everything we build. Momentum – We take initiative, share ideas, and keep moving forward. Accountability – We take responsibility for our work and give honest, respectful feedback. Hard work – We believe success comes from teamwork, dedication, and consistent effort. Learning agility – We stay curious, learn from mistakes, and continue improving. Adapt and thrive – We welcome change and see challenges as opportunities to grow. Win together – We work as one team, communicate openly, and support our shared goals.

🏢 Summary: Senior Frontend React Developer role focused on building scalable Next.js applications that power enterprise AI interfaces, including chat, semantic search, and knowledge graph features. The position involves developing high-performance, real-time, and data-intensive user interfaces with strong emphasis on accessibility, security, and code quality. You will contribute to reusable design systems, performance optimization, and AI-assisted development in a modern tech stack. 🗂️ Requirements: 5+ years frontend development experience, 3+ years experience with React, Strong knowledge of JavaScript, Strong knowledge of TypeScript, Strong knowledge of Next.js including SSR, App Router, Server Components, Advanced TypeScript skills, Experience with modern CSS solutions (Tailwind CSS or CSS-in-JS), Experience with complex state management, Experience with real-time collaboration features, Experience building AI-related interfaces (chat, streaming, semantic search), Understanding of localization, Understanding of accessibility standards, Understanding of security standards, Experience with AI coding tools (OpenAI Codex or Claude), Upper-Intermediate (B2) English or higher 📃 Skills: React, Next.js, JavaScript, TypeScript, SSR, Tailwind, CSS-in-JS, SWR, WebSockets, ReactFlow, Highcharts, Storybook, Playwright, Node.js, Python, AWS, S3, CloudFront, Lambda, OpenAI, Claude, Codex, Copilot, Puppeteer, Cypress, Lerna, Turborepo, Nx, MCP, DSPy 🏢 Description: About Us Many companies want to use AI agents, but these tools often have problems with real business tasks. We create a platform that helps AI understand company rules, workflows, and processes, so it can give correct and reliable answers. Our technology is trusted by large international companies and works with leading AI and cloud platforms. Our goal is to help people find better answers and make better decisions with AI. Senior Frontend React Developer As a Frontend React Developer, you will build modern user interfaces that make enterprise AI easy to use and reliable. You will create Next.js applications that work with large amounts of data, real-time AI responses, and advanced business features. Your work will help thousands of users access important information quickly and confidently. What You Will Do Design and develop scalable Next.js SSR applications. Build interfaces for AI chat, semantic search, knowledge graphs, and AI builders. Create data visualizations using libraries such as React Flow and Highcharts. Develop multilingual, accessible, secure, and cross-browser compatible applications. Work with SWR for data fetching, caching, and real-time websocket updates. Build and maintain reusable UI components and a Storybook design system. Improve application performance, monitor Core Web Vitals, and write automated tests with Playwright. Use AI coding assistants to speed up development while keeping high code quality. Participate in code reviews, share knowledge, and support continuous learning within the team. Requirements At least 5 years of frontend development experience. More than 3 years of experience with React and JavaScript/TypeScript. Strong knowledge of Next.js, including SSR, App Router, and Server Components. Advanced TypeScript skills and experience with modern CSS solutions such as Tailwind CSS or CSS-in-JS. Experience building applications with complex state management, real-time collaboration, and high performance. Experience creating interfaces for AI features such as chat systems, streaming responses, or semantic search. Understanding of localization, accessibility, security standards, and writing maintainable code. Experience using AI coding tools such as OpenAI Codex or Claude. Upper-Intermediate (B2) or higher English communication skills. Nice to Have Experience with React Flow, Highcharts, or similar visualization libraries. Basic backend knowledge in Node.js or Python and experience discussing API design. Experience with vector search, RAG interfaces, or semantic search solutions. Familiarity with MCP, DSPy, or other AI frameworks. Experience with monorepo tools such as Lerna, Turborepo, or Nx. Knowledge of AWS services like S3, CloudFront, and Lambda. Experience with Playwright, Puppeteer, or Cypress. 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, v0, MCP Servers, and credits for testing new AI technologies. Our Values We believe our success comes from the way we work together: Quality – We aim for excellent work and high standards in everything we do. Momentum – We take initiative and keep projects moving forward. Accountability – We take responsibility and give honest, respectful feedback. Hard Work – We solve difficult problems together and stay committed to our goals. Learning – We are curious, improve every day, and learn from mistakes. Adaptability – We accept change and see challenges as opportunities. Teamwork – We communicate openly, support each other, and succeed as one team.

🏢 Summary: Senior Frontend React Developer role focused on building enterprise-grade AI-native Next.js applications with complex state, real-time AI interactions, and scalable frontend architecture. The position involves owning frontend systems end-to-end, including UI design, performance optimization, accessibility, and production reliability. Engineers work closely with AI-driven products and modern tooling in a high-ownership environment. 🗂️ Requirements: 5+ years frontend engineering experience, 3+ years React experience, Modern TypeScript expertise, Production Next.js SSR experience, Knowledge of SSR, SSG, and CSR trade-offs, Complex state management experience, Experience building AI/LLM interfaces, Performance optimization and Core Web Vitals knowledge, Enterprise application development experience, Accessibility and localization knowledge, Security-conscious engineering approach, Daily use of AI coding agents, Clear technical communication skills 📃 Skills: React, TypeScript, Next.js, SSR, SSG, CSR, JavaScript, LLM, AI, CoreWebVitals, Accessibility, Localization, Security, ReactFlow, Highcharts, Node.js, Python, RAG, Codex, Claude, Copilot, GitHub 🏢 Description: About Shelf The enterprise is going agentic and we are creating a unique operating system for an automated future. Most AI agents break the moment they hit real business complexity. That’s why we built a platform that models a company's policies, workflows, and operational logic into an AI Data Model. Shelf enables AI Agents to reliably reason and deliver precise and reliable outcomes at scale. We already have what most AI startups are still trying to earn: Enterprise customers such as Glovo, Nespresso, and HelloFresh, real production data, and tens of thousands of users. Customers trust us with operational knowledge: Our platform is highly reliable and secure with SOC2, HIPAA-ready security practices, and mature integrations in place. Location – Warsaw, work from the office. Senior Frontend React Developer: This role is for a senior frontend engineer who can design and own business-critical user experiences for agentic AI products. We want someone who is strong technically, has strong UI judgment, communicates clearly, and has the taste to make complex product experiences simpler, faster, more trustworthy, and easier to evolve over time. Expect real ownership from frontend architecture through production quality. You will build production Next.js applications with complex state, real-time AI interactions, and multiple layers of enterprise functionality. The team is small enough for engineers to make real decisions. Career growth comes from ownership. Titles matter less than the scope you can carry. The people who grow fastest take responsibility for larger product surfaces, drive customer outcomes, and strive to develop better engineering practices. You solve ambiguous frontend problems by understanding the user need, shaping the right interaction model, then shipping, iterating, and keeping the experience healthy in production. We build AI-native. Engineers use Codex, Claude Code, and agents they build themselves. We invest in harness engineering through skills, CLIs, logs, traces, and orchestration. This is a role for someone in a high-growth chapter of their career, who wants to do the best work of their life, learn fast, and win as part of a team going all-in on a hard mission. What You Will Own Design and ship production Next.js SSR applications with complex state, high-load scenarios, and real-time AI interactions at scale Build interfaces for AI-powered features: streaming LLM responses, semantic search across millions of documents, interactive knowledge graphs, and agentic builders Architect component libraries and maintain the design system, ensuring reusability, accessibility, and consistent UX across the platform Deliver enterprise-grade functionality: localization, accessibility compliance, cross-browser support, and security Take full ownership after launch: monitor performance in production, optimize bundle sizes, instrument for Core Web Vitals, and ensure things scale gracefully Keep the bar high on code quality, testing, and craft through thoughtful code review and mentorship What Strong Performance Looks Like You turn vague product problems into shipped, well-reasoned interfaces that users trust Complex AI behavior feels legible and controllable to users because of how you built the UI Your components are reusable, accessible, and fast under real enterprise load You bring momentum. Work moves because you are on it What We Are Looking For Over 5 years of frontend engineering experience, including 3+ years specializing in React and modern TypeScript Production Next.js experience: SSR applications at scale, app router, server components, and the trade-offs between SSR, SSG, and CSR Complex state management for hard scenarios: real-time collaboration, optimistic updates, multi-tenant isolation, large-scale data sync Experience building AI/LLM interfaces: streaming token responses, chat UIs, semantic search, or similar real-time AI interactions High-load performance work: you monitor Core Web Vitals and know how to improve them under heavy traffic and large datasets Enterprise application depth: localization, accessibility, security, and compliance, you understand the complexity beyond "making it work" A security-conscious approach to engineering: you handle sensitive data carefully and think about the security implications of what you ship Strong craft and product instinct: you don't wait for perfect designs, you spot UX issues and propose solutions, and you're never satisfied with "good enough" AI-native working style. You already use AI coding agents daily and are eager to push the boundaries of harness engineering Clear communication. You articulate design decisions and technical trade-offs clearly, verbally and in writing Strong Plus Experience with React Flow, Highcharts, or other complex data-visualization libraries Hands-on experience with vector search UIs, RAG interfaces, or generative UI Understanding of Node.js/Python: you can read backend code and contribute to API design discussions Built or contributed to design systems or open-source component libraries How We Evaluate Fit We care more about craft, ownership, and the ability to make complex AI feel trustworthy than a perfect match to every library on paper. If you are the kind of engineer who can take a messy, complex enterprise problem and turn it into an interface people trust, we want to talk. What Shelf Offers: B2B contract Company Stock Options Hardware: MacBook Pro Modern technical stack. Develop open-source software A strong AI-native engineering environment with modern tools and room to experiment, including Claude Code, OpenAI Codex, and GitHub Copilot Why Shelf Becoming one of the defining companies of the AI age is a hard plan, and our leadership team has the rare mix of deep AI, knowledge-management, and enterprise SaaS experience to actually execute it We have raised over $60 million in funding; our investors include Tiger Global, Insight Partners, Base10, and others Recognized by Gartner as a Cool Vendor, with high-velocity growth powered by the most innovative product in our category We love our customers and our customers love us. Ask a Shelf customer why, and they'll tell you it's our innovative capabilities and rock-solid reliability, that they enjoy working with our people, and most of all, the improvements they see in their business KPIs We're building fast across three hubs: our New York HQ and our Product and Engineering centers in Warsaw and Lviv