About the role

Build and scale secure APIs for a financial client.
Focus on API design and developer experience.
Drive delivery with a quality-first mindset.
Work independently on spec-driven development.
Hands-on experience with AWS is mandatory.

Skills the posting asks for

TypeScript
Node.js
AWS

Summarised from the employer’s posting, which is reproduced in full below.

The employer’s full posting

Backend Engineer - API Development (TypeScript / Node.js)

As a preferred supplier to one of our biggest Financial Client, I am seeking for a Backend Engineer - API Development (TypeScript / Node.js) for a position in Amsterdam, Netherlands. The successfully candidate is 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.

Where you 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

Core skills requirement:

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). Given the short timeline and MVP nature, we prefer they not need to onboard onto a new cloud;
Cloud-native delivery - building and shipping containerized services, infrastructure-as-code (Terraform ideal), CI/CD pipelines
Observability - structured logging, metrics, tracing, and audit trails; can debug production from telemetry

Nice-to-haves:

fintech or other regulated-domain experience
platform / API-gateway team background
leading a small delivery independently

Contract: 12+ month

Rates: Excellent

Location: Amsterdam

Interview: 2 stages

Nick Chinweerapunt

Account Manager

Gazelle Global Consulting

Tel +31 85 111 0171

Tel +44 203 588 7747

Mob +44 7377 403 773

nick@gazellegc.com