Senior Full Stack Typescript Engineer (AI)

Kindgeek is looking for a full stack engineer (AI) who thinks in systems, not in tools — someone who can look at a tangle of AI agents, documents, and predictions and design where each one's judgment ends and the next one's begins. Your mission will be to build and operate the AI Product Systems platform for our US-based fintech client, where LLM agents extract and reconcile data from real, messy documents, ML models predict and score, and deterministic logic owns every number that matters. This is a small, senior team — you'll own problems end-to-end and be trusted to make the call when the path isn't obvious yet. RESPONSIBILITIES As a Senior Full Stack Engineer (AI), you will be responsible for : Designing multi-agent extraction pipelines that let specialized agents find and use only the context relevant to their task, without over-loading them or relying on naive keyword search; Building AI-powered product features — structured extraction, tool use, multi-agent workflows — with validation and clear boundaries against deterministic business logic; Owning features end-to-end, from an ambiguous business problem through Postgres schema, API contracts, background workflows, and UI, and staying responsible for how they behave in production; Designing durable, event-driven workflows that handle retries, partial failure, and idempotency across third-party integrations that fail unpredictably; Integrating in-house ML predictions into product surfaces, handling timeouts and low confidence without fabricating a value; Building interfaces people work in all day — review queues, collaborative forms, and long multi-step flows in Next.js and React, where correctness of state matters as much as visual polish; Making AI and ML behavior measurable through tracing, evaluation, and iteration, so quality is something the team observes rather than assumes. REQUIREMENTS We're looking for a Senior Full Stack Engineer (AI) who has : Production experience designing or operating multi-agent AI systems, including how agents store, catalog, and hand off extracted context to each other — not just RAG over a vector store; Practical experience shipping at least one LLM-powered feature to production, and can describe a specific failure mode you found and how you contained it; Hands-on daily use of AI coding tools (e.g. Claude Code, Codex, or equivalent), with clear judgment about what to verify before trusting their output; Production TypeScript and Node.js backend experience with typed API contracts (tRPC, GraphQL, or equivalent) and schema validation at the boundary; Modern React experience (Next.js App Router or comparable), with disciplined handling of server state, caching, and complex forms; PostgreSQL schema design and migration experience against live data; Experience with asynchronous, event-driven backend work — job queues or durable workflow engines — and the operational instincts that come from running them; Comfort consuming ML predictions in application code, understanding confidence and uncertainty well enough to decide what the product does when a model is wrong or unavailable; The ability to walk through a real technical trade-off you made and the reasoning behind it — the criteria you weighed, not just the theory of how it should work; Strong spoken English and direct, low-ego communication, comfortable working closely with a US client in a small team. Will be a plus: Document ingestion and extraction experience across mixed-format files (OCR, PDFs, structured + unstructured data); Prior experience in fintech, regtech, or another regulated, high-trust domain; SSO, SAML, OIDC, or multi-tenant authorization experience. WHAT WILL YOU GET WITH KINDGEEK We want you to thrive and feel supported Professional growth: at Kindgeek, we want our employees to grow and achieve ambitious professional goals. We support professional development with training and certification refunds and provide regular feedback and technical reviews. Benefits package: Kindgeek offers all team members competitive compensation and a benefits package that includes 18 working days of fully paid vacation, 10 compensated by 50% sick leaves without a note from the doctor, and an opportunity to take study leaves. Depending on how long you stay in the company, you can receive different health insurance packages from our partners. Personal growth: as a part of our team, you will have access to corporate English courses with a 50% reimbursement, take advantage of our offline library and access a large selection of corporate training and classes. Also, every employee can request any internal or external training or certification if it applies to his or her work responsibilities. Geek community: at Kindgeek, we value community – even in the full-scale invasion times, we take every opportunity to stick together. Our geeks organise various online and offline clubs – from stretching and skiing to English. We volunteer together and support each other. Flexibility: Kindgeek offers a hybrid working model. Team members can work remotely or from the office or Kindgeek London Hub – an innovative cafe-style co-working in Lviv (it's pet-friendly!). We encourage you to apply At Kindgeek, we encourage everyone to apply – regardless of nationality, race, gender, marital status, disability, sexual identity, or religion. We are growing into an inclusive, equal-opportunity company where only professionalism, competence, and ideas matter. We are committed to supporting mobilised employees and veterans joining Kindgeek and facilitating their career development. We aim to bring equal opportunities to all team members and candidates – especially those underrepresented in technological companies.