Frontend Engineer

🏢 Summary: Mid-level React/TypeScript Engineer role focused on building and owning production-grade frontend applications (dashboards, operator panels, customer apps) on top of AI agent systems. The position involves close collaboration with backend services and active use of AI coding tools while maintaining strong engineering judgment and code quality. You will take full ownership of features from design to deployment in a production environment with real users. 🗂️ Requirements: 3–5 years commercial experience in frontend development, Strong proficiency in TypeScript, Deep understanding of React and rendering lifecycle, Experience building scalable frontend architectures, Experience integrating with REST APIs and authentication systems, Ability to work with backend technologies (Node.js or Python), Experience with state management and data synchronization, Proficiency with Next.js, Experience working with MongoDB, Experience deploying or working with AWS, Ability to use AI coding tools critically and effectively 📃 Skills: TypeScript, React, Next.js, Tailwind, Node.js, Python, MongoDB, AWS, REST, Claude, Cursor, MCP 🏢 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. 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're small, technical, AI-heavy, and we ship. Who we're looking for A solid React engineer who actually understands what's happening under the hood, and uses AI tools daily without outsourcing their brain to them. You'll join the team that owns the user-facing layer of our products: the dashboards, the operator panels, the customer-facing apps that sit on top of the agents. We need someone we can trust to take a feature, build it well, and ship it without it coming back broken three days later. This isn't a flashy role and we're not looking for a flashy person. We need craftsmanship. If you read a ticket and your first instinct is "what's the data model, what's the component structure, where does state actually live" - keep reading. If your first instinct is "I'll just vibe-code it with Cursor and hope the PR passes" - this isn't for you, and that's fine. What we mean by "good React engineer" You write TypeScript well: types help you, they don't slow you down You understand React deeply enough to debug a re-render problem without guessing You can structure a non-trivial frontend so it doesn't turn into a tangle in six months You've worked with a real backend: REST, auth, data sync, edge cases — and you can hold both ends of a feature in your head You read other people's code carefully and review like an adult: kindly, but honestly You are comfortable using AI tools daily, but you do not outsource your judgment to them You know how to check AI-generated code instead of trusting it because it “looks right” ~3–5 years of commercial experience is roughly where we expect this person to sit. Less is fine if you're sharp; more is fine if you actually want a Mid role. How we work with AI We use AI heavily. Claude Code, Codex, Cursor, MCP, agent workflows: they're a normal part of how we work, the same way Git or Docker is. You'll be expected to use them the same way: not as a gimmick, not as a shortcut around understanding the codebase, but as leverage. That means: break work into clear chunks, guide the tools through implementation, review their output critically, fix what's wrong, and own the final result. You should be faster with these tools than without them - and you should know exactly where they're about to lie to you. AI doesn't turn a bad engineer into a good one. It just makes them ship faster, which is worse. So: We do not want people who only know how to prompt. We also do not want people who proudly refuse to use AI and treat it like autocomplete with better marketing. The right person sits in the middle: strong fundamentals, strong taste, strong ownership - multiplied by modern AI tooling. What you'll actually own Frontend, day-to-day. React, TypeScript, Tailwind, Next.js. Real product surfaces - operator dashboards, customer panels, internal tools that real people use to do real work. Fullstack when needed. You won't live exclusively in the frontend. Node/Python on the backend when a feature needs it - you don't have to be an expert, but you have to be willing. Quality. The thing you ship works, doesn't break the next thing, and doesn't make the codebase worse. We notice this. Working with the team. Code reviews, architecture decisions - we figure out the harder calls together. You're not coding in a vacuum. The stack TypeScript / React / Next.js · Tailwind · Node.js · Python (some) · MongoDB · AWS · Claude / Cursor / MCP for tooling. We don't use Go. Nice-to-have (not required) You've built a side project that you actually shipped, not just started You've worked with LLM APIs in production (not "I made a chatbot in a tutorial") You care about UX - not as a designer, but as someone who notices when something feels wrong What we offer 13 000 – 18 000 PLN netto + VAT, B2B Remote-friendly, Poland-based A small team that ships and doesn't waste your time Direct work with the founders - no Jira theater, no three-round groomings, no PM filtering your ideas Modern AI tooling fully paid for (Claude Max, Cursor, Codex, whatever helps you work better) Real ownership of the frontend layer of a product people use every day 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: 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: 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: 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: Technical leadership role focused on building and scaling an AI Engineering Lab that develops multi-agent systems and internal tools powered by LLMs to enhance engineering productivity. The position combines hands-on software development, architectural decision-making (build vs. integrate), and full lifecycle ownership from prototyping to production. The role emphasizes high-performance system design, AI integration in production, and cross-functional collaboration. 🗂️ Requirements: High proficiency in Python, Significant experience with at least one of: Java, Go, TypeScript, Scala, Hands-on experience integrating LLMs into production environments, Proven ability to evaluate third-party tools vs custom-built solutions, Experience designing distributed systems and multi-agent architectures, Ability to define technical roadmaps and drive high-level system design, C1 level English, C1 level Polish 📃 Skills: Python, Java, Go, TypeScript, Scala, LLM, AgenticAI, LangChain, AutoGen, Vercel, MCP, AWS, GCP, Azure, Docker, Kubernetes, DistributedSystems, API 🏢 Description: We are: RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Our proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to achieve outstanding results and meet their goals at every stage of the funnel. Join RTB House and lead our AI Engineering Lab, a team dedicated to pioneering innovation and boosting engineering productivity by leveraging the latest advancements in Agentic AI. We are looking for a hands-on technical leader with a strong, traditional software engineering background. In this role, you won't just be writing custom code from scratch. You will be an architect of efficiency. Our approach is highly pragmatic: we build internal tools and autonomous agents to supercharge our engineering workflows. You will be expected to navigate the "build vs. buy/integrate" landscape, determining when to leverage off-the-shelf LLM products and when to architect a custom, high-performance solution. You will: Drive Technical Excellence: Act as a technical pillar within the Lab, implementing high-standard code and sophisticated system designs. You will mentor mid-level peers and lead deep-dive code reviews. Architect Multi-Agent Systems: Design and deploy distributed systems and multi-agent architectures that automate complex engineering tasks. You will own the architectural decisions for "build vs. integrate" strategies. Innovate with Agentic AI: Spearhead the evaluation and prototyping of LLMs, Agentic frameworks, and Model Context Protocols (MCPs). You will transform theoretical AI advancements into production-ready tools. Own the Full Lifecycle: Take responsibility for the entire development cycle. From initial concept and API integration to production deployment and long-term scalability. Influence Product Strategy: Partner with Product and Engineering Managers to ensure the Lab’s innovations align with the broader company roadmap and provide measurable ROI to our developers. Desired experience: Pragmatic Architect: Proven ability to evaluate third-party tools and vendor solutions against custom-built software to find the most efficient path forward. Technical Stack: High proficiency in Python is mandatory. Significant experience with at least one other language (Java, Go, TypeScript, or Scala) is highly preferred. AI/ML Implementation: Hands-on experience integrating LLMs into production environments. Systems Thinker: Ability to define technical roadmaps for specific features and drive high-level design choices that prioritize maintainability and performance. C1 level in English and Polish. Nice to have: Direct experience building internal developer tools, custom Model Context Protocols (MCPs), or using Agentic AI frameworks (e.g., Vercel AI SDK, LangChain, AutoGen, Agent Development Kit). Experience with cloud platforms (AWS, GCP, Azure) and containerization technologies (Docker, Kubernetes). Familiarity with the ad-tech industry and real-time bidding (RTB) systems. We offer: Projects focused on extreme performance and high code quality – clean code and solid code reviews are our standard. Collaboration within an interdisciplinary, self-sufficient team (including DevOps, database experts, backend developers, product designers, and QA engineers). Access to modern technologies and the opportunity to apply them in large-scale, high-impact projects. Cooperation based on B2B contract. You can cooperate 100 % remotely or choose one of our office spaces in Warsaw or Cracow.

🏢 Summary: Technical leadership role focused on building and scaling an AI Engineering Lab that develops internal tools and multi-agent systems to enhance engineering productivity. The position combines hands-on software engineering with architecture design, LLM integration, and build-vs-buy decision making. You will drive end-to-end development of Agentic AI solutions from prototype to production in a high-performance environment. 🗂️ Requirements: High proficiency in Python, Significant experience with at least one of: Java, Go, TypeScript, Scala, Hands-on experience integrating LLMs into production environments, Experience designing distributed systems and multi-agent architectures, Ability to evaluate third-party tools vs custom-built solutions, Experience with system design and defining technical roadmaps, Ability to lead code reviews and mentor engineers, C1 level English, C1 level Polish 📃 Skills: Python, Java, Go, TypeScript, Scala, LLM, AgenticAI, LangChain, AutoGen, Vercel, MCP, AWS, GCP, Azure, Docker, Kubernetes, APIs, DistributedSystems 🏢 Description: We are: RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Our proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to achieve outstanding results and meet their goals at every stage of the funnel. Join RTB House and lead our AI Engineering Lab, a team dedicated to pioneering innovation and boosting engineering productivity by leveraging the latest advancements in Agentic AI. We are looking for a hands-on technical leader with a strong, traditional software engineering background. In this role, you won't just be writing custom code from scratch. You will be an architect of efficiency. Our approach is highly pragmatic: we build internal tools and autonomous agents to supercharge our engineering workflows. You will be expected to navigate the "build vs. buy/integrate" landscape, determining when to leverage off-the-shelf LLM products and when to architect a custom, high-performance solution. You will: Drive Technical Excellence: Act as a technical pillar within the Lab, implementing high-standard code and sophisticated system designs. You will mentor mid-level peers and lead deep-dive code reviews. Architect Multi-Agent Systems: Design and deploy distributed systems and multi-agent architectures that automate complex engineering tasks. You will own the architectural decisions for "build vs. integrate" strategies. Innovate with Agentic AI: Spearhead the evaluation and prototyping of LLMs, Agentic frameworks, and Model Context Protocols (MCPs). You will transform theoretical AI advancements into production-ready tools. Own the Full Lifecycle: Take responsibility for the entire development cycle. From initial concept and API integration to production deployment and long-term scalability. Influence Product Strategy: Partner with Product and Engineering Managers to ensure the Lab’s innovations align with the broader company roadmap and provide measurable ROI to our developers. Desired experience: Pragmatic Architect: Proven ability to evaluate third-party tools and vendor solutions against custom-built software to find the most efficient path forward. Technical Stack: High proficiency in Python is mandatory. Significant experience with at least one other language (Java, Go, TypeScript, or Scala) is highly preferred. AI/ML Implementation: Hands-on experience integrating LLMs into production environments. Systems Thinker: Ability to define technical roadmaps for specific features and drive high-level design choices that prioritize maintainability and performance. C1 level in English and Polish. Nice to have: Direct experience building internal developer tools, custom Model Context Protocols (MCPs), or using Agentic AI frameworks (e.g., Vercel AI SDK, LangChain, AutoGen, Agent Development Kit). Experience with cloud platforms (AWS, GCP, Azure) and containerization technologies (Docker, Kubernetes). Familiarity with the ad-tech industry and real-time bidding (RTB) systems. We offer: Projects focused on extreme performance and high code quality – clean code and solid code reviews are our standard. Collaboration within an interdisciplinary, self-sufficient team (including DevOps, database experts, backend developers, product designers, and QA engineers). Access to modern technologies and the opportunity to apply them in large-scale, high-impact projects. Cooperation based on B2B contract. You can cooperate 100 % remotely or choose one of our office spaces in Warsaw or Cracow.

🏢 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-career Software Engineer role focused on building AI-native and agentic systems for wealth management technology using AI-assisted development practices. The position involves contributing to production systems, participating in the full software delivery lifecycle, and collaborating on scalable automation and workflow solutions. Candidates should have strong software engineering fundamentals, AI tool fluency, and an interest in modern cloud and AI-driven development. 🗂️ Requirements: B.S. in Computer Science or equivalent work experience, 0-3 years of professional software engineering experience, Strong foundational knowledge of data structures and algorithms, Understanding of system design basics, Ability to build solutions in at least one programming language, Understanding of APIs and cloud concepts, Experience with AI-assisted development tools, Knowledge of modern software delivery practices, Ability to work with ambiguous problems, Willingness to participate in code reviews and architecture discussions 📃 Skills: AI, APIs, AWS, SaaS, LLM, Cloud, Algorithms, Python, Java, Testing, Deployment, Observability, Automation, Prompting 🏢 Description: Vestmark is building the AI-native future of wealth management technology. We are looking for early-career Software Engineers in Boston who are serious about AI-assisted development, curious about how software engineering is changing, and ready to do real work on systems that matter. You will not be handed a ticket queue. You will be expected to think, build, and grow quickly in an environment where AI fluency is the baseline, not the aspiration. This role is based out of the Boston office in the Seaport District. Vestmark is a leading provider of wealth management solutions and services that enable financial advisors and institutions to efficiently manage and trade their clients' portfolios using a purpose-built SaaS ecosystem. With over $2 trillion in assets and 5+ million accounts, we are a trusted partner to some of the largest and most respected players across the wealth management industry. What You'll Do Build Agentic Systems - Contribute to the design and delivery of agentic systems: workflows where AI plans, executes, and iterates toward outcomes rather than simply responding to requests - Build and ship production-quality solutions as part of a squad working on real efficiency and automation problems with direct business impact - Participate in the full delivery lifecycle: design discussions, development, testing, deployment, and iteration Apply AI-Native Development Practices - Use AI-assisted development tools, including code generation, prompt engineering, and agentic frameworks, as a standard part of your daily workflow from day one - Learn and apply the team's standards for building AI-native systems: state management, observability, non-determinism, and inference cost awareness - Engage with testing and validation approaches specific to adaptive systems where behavior is not fully deterministic Contribute to Reusable Foundations - Create clean, testable, maintainable solutions that strengthen the team's shared foundation - Apply the principle "fix the process, don't automate the broken one" - Participate in code reviews as both a reviewer and a recipient Grow & Contribute to the Team - Engage actively in design reviews and architecture discussions - Take feedback seriously and apply it quickly - Contribute to the growth and development of the team's core values What We're Looking For Engineering Fundamentals - Solid foundational knowledge of software engineering, data structures, algorithms, and system design basics - Ability to build and deliver working solutions in at least one language - Understanding of APIs, cloud concepts, and modern software delivery practices AI Fluency & Curiosity - Hands-on familiarity with AI-assisted development tools - Curiosity about agentic systems and multi-step AI workflows - Awareness of evolving AI tooling trends Problem-Solving Orientation - Ability to work through ambiguous problems and propose solutions - Comfort working without fully defined solutions upfront - Attention to business context and impact Learning Velocity - Ability to learn quickly and independently - Receptive to feedback and continuous improvement - Evidence of intellectual curiosity through projects or open-source contributions Product Mindset - Interest in understanding business problems before implementing solutions - Ability to form and communicate a point of view on product decisions What Will Help You Stand Out - Experience with agentic frameworks, LLM APIs, or workflow orchestration tools - Experience with AWS or similar cloud platforms - Background in financial services, mathematics, or quantitative disciplines - Strong project or portfolio work Why Vestmark - Opportunity to build AI-native systems in production - Exposure to experienced Principal and Senior Engineers - Environment focused on AI engineering growth and development Education & Experience - B.S. in Computer Science or equivalent work experience; M.S. a plus - 0-3 years of professional software engineering experience - Strong internship or personal project experience considered - Demonstrated AI tool fluency valued highly Vestmark takes a market-based approach to compensation to ensure fair and competitive pay. Compensation depends on skills, experience, qualifications, job scope, and location. In addition to base salary, Vestmark offers a comprehensive total rewards package, including equity grants, company-paid medical premiums, competitive time off, and other eligible compensation. Salary range: $80,000—$110,000 USD