Hire senior API developers who design APIs that last
Senior engineers who treat an API as a contract: designed first, versioned with care, secured by default and documented well enough that partners never need to ask.
By the Ryz Labs team · Updated October 2026
When you hire API developers through Ryz Labs, you add senior back-end engineers who design the contract before they write the handler, and who know what breaks when thousands of clients depend on it. They are the top 1% of the engineers we interview. They join your platform or product team, work in your repos and review queue, and keep US business hours.
What our API developers work on
"API developer" covers several jobs. Some teams need someone to design a public API that partners will build against for years. Others need an engineer to wire up a dozen third-party APIs without losing data when one of them times out. Our engineers have done both, in Node.js, Python, Go, Java and .NET. If you would rather hand a whole API program to a Ryz team, that is our API development service. This page is about hiring individual engineers to join your team. Typical work:
- Public and partner APIs designed from an OpenAPI 3.1 spec, with consistent resource naming, error formats such as RFC 9457 problem details, and developer docs generated from the spec.
- Internal service APIs using gRPC and Protocol Buffers between services, or REST behind an API gateway like Kong, AWS API Gateway or Apigee.
- GraphQL layers that sit over existing services, with schema design, DataLoader batching and query cost limits.
- Third-party integrations with payment, messaging, CRM and ERP providers, including retries, backoff, idempotency and reconciliation jobs.
- Webhooks and event APIs: signed payloads, delivery retries, replay endpoints and AsyncAPI specs for Kafka or SNS topics.
- APIs for AI agents: tool definitions and MCP servers that let models call your services with scoped permissions.
- Versioning and migrations: moving clients from v1 to v2 without breaking them, with deprecation headers, sunset dates and usage tracking.
Skills we vet for
- Resource and contract design: modeling nouns and state transitions, pagination (cursor versus offset), filtering, partial responses and consistent error shapes.
- Design-first workflow: writing the OpenAPI or protobuf contract first, linting it with Spectral or buf, and generating clients, mocks and docs from it.
- Authentication and authorization: OAuth 2.0 flows, OpenID Connect, JWT validation, API keys with scopes, mTLS between services, and object-level authorization checks.
- API security: the OWASP API Security Top 10, especially broken object level authorization, mass assignment and unrestricted resource consumption.
- Reliability under load: idempotency keys, rate limiting with token buckets, timeouts, circuit breakers and safe retries on the client side.
- Versioning strategy: URL versus header versioning, additive change rules, and how to retire fields without breaking mobile apps you cannot force-update.
- Testing: contract tests with Pact, property-based API testing with Schemathesis, and integration suites that run against real dependencies in containers.
- Observability: OpenTelemetry tracing across services, structured logs with request IDs, and per-consumer metrics for latency and error rate.
How we vet API developers
Recruiters source back-end engineers who have owned APIs in production, not just consumed them. ARC, our in-house system, ranks the pipeline so recruiters spend time on the strongest people. Each candidate completes a structured NTRVSTA AI interview built around API design, security and failure handling. Recruiters review every candidate before and after that interview and assemble a curated shortlist for you. AI scores are advisory. Humans make the decisions.
Sample interview topics
- A client retries a POST /payments request after a network timeout and the customer is charged twice. Design the fix end to end, including where the idempotency key is stored and how long it lives.
- Your list endpoint uses offset pagination, and partners report missing and duplicated rows while data is changing. Explain why, and design a cursor-based replacement that existing clients can adopt gradually.
- A user can read another tenant's invoice by changing an ID in the URL. Where did authorization fail, and how do you prevent the whole class of bug, not just this endpoint?
- You need to rename a field used by an iOS app that a third of users never update. Walk through the change, the deprecation signals and how you decide when the old field can go.
- Your webhook consumers complain about missed and out-of-order events. Design delivery, signing, retries and a replay mechanism, and say what guarantees you will document.
Ways to hire API developers
| Option | Best for | Trade-offs |
|---|
| Freelance marketplace | One well-defined integration with a documented third-party API | Little say in long-term design; the person who knows the edge cases leaves when the gig ends |
| Staffing or recruiting agency | A permanent back-end hire | Screens often check frameworks, not contract design or security; placement fees and long searches |
| In-house recruiting | The long-term owner of your public API and platform | Slow, and hard to judge API design depth from a resume |
| Ryz Labs staff augmentation | Adding senior API engineers to your platform or product team | Custom quote, scoped per team; your architects keep ownership of the contract |
| Ryz Labs dedicated team | A new partner API, a gateway rollout or an integration program with its own tech lead | Larger commitment; works best once the scope is clear enough to staff a team |
Ryz is not the right fit if you want to book a few hours of integration work through a self-serve marketplace. It is also the wrong choice if your API team needs follow-the-sun coverage across Europe and Asia.
Why US business hours matter for API work
API work is coordination work. A breaking change has to be agreed with the mobile team, the partner engineers and whoever owns the gateway. An incident at 2 p.m. Eastern needs the person who wrote the retry logic on the call, not reading about it the next morning. Our engineers work your hours, so design reviews, contract changes and incident calls happen in real time with US teams.
Clear written English matters here too. API engineers write specs, changelogs, migration guides and error messages that outside developers read. We look for it during vetting, because a well-designed endpoint with a confusing doc still generates support tickets.
Related roles
FAQ
Is an API developer different from a back-end developer?
Most API developers are back-end engineers, but not every back-end engineer is good at API design. If your API is consumed by partners, mobile apps or AI agents, tell us. We shortlist people who have designed and versioned APIs that outside clients depend on, not only internal endpoints.
Can they work in our language and framework?
Yes. We match on your stack, whether that is FastAPI, NestJS, Spring Boot, ASP.NET Core or Go. The design skills carry across languages, but day-to-day work goes faster when the framework is familiar.
How much does it cost to hire an API developer through Ryz?
Typical cost is $7,000 to $15,000 per engineer per month. Mid-level engineers run $7,000 to $10,000 and senior engineers $10,000 to $15,000. Every quote is scoped per team, and you get a plan, a price and the names of the people before you start.
What hours do they work?
US business hours, including New York hours, with same-day code review. Our engineers work remotely across the Americas and join your standups, design reviews and on-call rotations as you set them up.
Can they help us expose our APIs to AI agents?
Yes. We can shortlist engineers who have built MCP servers and tool definitions over existing services. The same rules apply as for any client: scoped credentials, rate limits and clear error messages the model can act on.
Questions we didn't answer? Email info@ryzlabs.com.