Senior full-stack engineer, applied AI

Ainurhq; Netherlands; Remote; EUR 120,000 - 170,000; Full time

Job summary

Ainur is looking for a senior full-stack engineer to integrate language models into client software in the Netherlands and EU. You will build prompts, tools, evaluation, and the API, data, and UI layers to support model-driven features.

Stack includes TypeScript and Go, PostgreSQL with pgvector, model providers, and our own agent tooling. You will ship end-to-end systems with real users and strict data controls.

Qualifications

• Seven or more years building software for production.
• Senior in TypeScript across the stack, with Go or Python where needed.
• Hands-on with model APIs, tool calling, embeddings and evaluation.
• Careful with personal data and client agreements.
• Fluent English communication with clients.

Responsibilities

• Operate a model-driven conversation with real users and call tools against client systems.
• Develop recommendations and personalization features with learning and opt-out options.
• Enable retrieval over client documents with citations and access control.
• Build evaluation workflows: test sets, regression runs, and client dashboards.
• Create and maintain agent tooling and AI-written code review standards.

Skills

TypeScript

Go

Python

Model APIs

Tool calling

Embeddings

Evaluation

English communication

Tools

PostgreSQL

pgvector

Job description

Ainur is an engineering and research firm in the Netherlands. We build and run software for our clients, and we are looking for a senior full-stack engineer who puts language models to work inside those products: an operator that handles a conversation and hands off to a person, a recommender that learns from what users do, retrieval over a client's own data.

The role

AI is one part of every system we build. The model answers a support chat and books the appointment. The system around it decides what the model may see, when it hands off, and how we know it is doing well. You build both halves: the prompts, tools and evaluation on one side, and the API, data and UI on the other. Stack: TypeScript and Go, PostgreSQL with pgvector, the model providers that fit the client's data agreements, and the agent tooling we use on our own work.

What you will work on

• Operators inside existing processes: a model that runs a conversation with real users, calls tools against the client's systems, and hands off to a person when it has to.
• Recommendation and personalisation: curated and learned feeds, shadow mode before go-live, weekly re-weighting, consent and opt-out built in.
• Retrieval over a client's own documents and data, with citations and access control.
• Evaluation: test sets, regression runs on every prompt change, and the dashboard that tells the client how it is going.
• Agent tooling for the team: MCP servers, review bots, and the standards that keep AI-written code reviewable.

What we are looking for

• Seven or more years building software for production, and at least one system with a model in the loop that real users depend on.
• Senior in TypeScript across the stack, with Go or Python where the service or the tooling needs it.
• Hands-on with model APIs, tool calling, embeddings and evaluation. You know when a smaller model, or no model, is the right answer.
• Careful with personal data: consent, retention, where the data goes, and what the agreement with the client allows.
• You can run a technical conversation with a client in English and write down what was decided.
• Based in the Netherlands, or elsewhere in the EU.
• Nice to have: pgvector or a vector database in production, fine-tuning open-weight models, Dutch.

What we offer

• 32 to 40 hours a week. In the Netherlands, employed or freelance. Elsewhere in the EU, freelance.
• Pay in line with the market and your experience.
• Remote by default. In the Netherlands, on site with a client when it matters.
• Work that is yours end to end, a designer next to you, and founders who still write code.
• English is the working language. Dutch is welcome.