Senior Backend Engineer AWS/API’s

Introduction 36 hours per week Start: 07 September 2026 End: 01 June 2027 Possible extension: Yes ZZP is allowed Hybrid way of work Candidates MUST live in the Netherlands at this moment Function Your new company We are New10, a financial service scale-up initiated by ABN AMRO Bank. At New10 we believe that business financing should be easy and accessible. We are on a quest to transform the financing ecosystem by using the speed and innovative strength of a fintech with the expertise and funding of a bank to deliver a fast, simple, and clear financing experience to SME businesses. Backend Engineer – API Development The role in one line: An independent backend engineer to help build, harden, and scale our secure APIs – strong on API craft, security, and testing, and able to help drive delivery, not just execute tickets.

Context: Work across our API surface, held to real financial-institution standards for security, reliability, and testing. It’s a deliberately simple, well-structured codebase. No internal/domain business knowledge required, that’s owned in-house. We need backend and API strength. Where they add the most value: Since internal logic is covered, their leverage is on the partner-facing platform and developer experience: – Growing the API surface cleanly (new endpoints, webhooks/callbacks, richer querying) – Developer experience – clear contracts, published API specs, integration docs, sandbox environments – Hardening – rate limiting, secret rotation, contract testing, pen-test remediation – Scaling – repeatable multi-partner onboarding, tenant isolation, load/performance testing, caching – Platform quality – SLOs, alerting, resilience patterns Ways of working: – Independent and self-directing – takes a capability from spec → design → tested delivery without hand-holding – Helps manage the work – can break down a body of work, sequence it, and drive it to a clear “done” – Spec- and documentation-driven – at home working from and writing specs, acceptance criteria, and decision records; a clear, concise writer – Comfortable with AI-assisted / agentic development – this project is built heavily with agentic tooling; someone who can direct and review that output well is a real multiplier – Quality-first and pragmatic – treats security, testing, and observability as ship-blocking, while favoring simple solutions over over-engineering Requirements Core skills: – Modern backend development in TypeScript / Node.js – server-side HTTP services, networking fundamentals, clean typed code – REST/JSON API design – versioning, consistent error contracts, idempotency, pagination, and an API-as-contract mindset (OpenAPI) – Relational data – schema design, migrations, and a data-integrity mindset – Asynchronous & queue-driven systems – background workers, job lifecycles, retries, idempotent processing – API security – token-based auth (OAuth/JWT), authorization and tenancy isolation, secure secret handling, “fail-closed” defaults, and awareness of industry baselines (e.g.

OWASP API Security Top 10) – Test-forward development – comfortable driving work through unit, integration, and contract tests as a first-class part of building, not an afterthought – Hands-on AWS experience (mandatory) – must know the specifics of core AWS services (containers/compute, queuing, managed databases, secrets, load balancing).

… lees de volledige omschrijving bij A2Z-CM.