REST, GraphQL & gRPC services
The right protocol for the job — REST for broad reach, GraphQL for aggregating a chatty front end, gRPC for internal service-to-service throughput.
09 — Interfaces
API Development Services
APIs that other teams can build on without asking you questions — versioned, documented, secured and monitored from the first release.
Overview
An API is a product with developers as users
An API is a product with developers as its users, and it fails the same way any product does: unclear contracts, breaking changes shipped without warning, error responses that say nothing useful, and documentation that stopped matching reality two releases ago.
We design APIs contract-first, generate documentation from the specification so it cannot drift, and treat versioning and deprecation as commitments rather than afterthoughts.
A
Contract-first design
The OpenAPI or schema definition is agreed and reviewed before implementation, so consumers can build in parallel.
B
Secure by construction
OAuth 2.0 and OIDC, scoped tokens, rate limiting and input validation applied at the gateway and again in the service.
C
Versioned promises
Backwards-compatible evolution, explicit deprecation windows and consumer usage tracking before anything is switched off.
What's included
The API work we do
Internal service interfaces, public developer platforms, and the gateway and governance layer that keeps both sane.
Authentication & authorisation
OAuth 2.0, OIDC, mTLS and API keys with scope design that reflects your real permission model rather than an all-or-nothing token.
Gateways, quotas & rate limiting
Kong, Azure APIM or AWS API Gateway configured with tiered quotas, throttling and per-consumer policies that protect your backends.
Documentation & developer portals
Generated reference docs, worked examples, a sandbox environment and changelogs — the difference between an API adopted and an API ignored.
Contract & load testing
Automated contract tests in CI that fail a build before a breaking change reaches a consumer, plus load profiles run against realistic traffic.
Monitoring & SLOs
Latency, error-rate and saturation dashboards per endpoint and per consumer, with alerting tied to the SLOs you publish.
How we work
Shipping an API
01
Consumer research
We start with the teams that will call it — their use cases, their constraints, and the calls they would otherwise make in a loop.
02
Specification & review
A written contract, a mock server consumers can code against immediately, and a review round before implementation starts.
03
Implementation & hardening
Services built against the contract, with authorisation, validation, pagination, idempotency and error semantics treated as first-class work.
04
Publish & operate
Portal, sandbox and changelog published together, then run against SLOs with usage tracked per consumer.
Why it pays off
What a well-run API changes
Integrations stop needing meetings
Good documentation and a sandbox mean a partner integrates without a standing weekly call with your engineers.
Breaking changes stop being incidents
Contract tests, versioning and consumer analytics turn a risky change into a scheduled, communicated one.
Capability becomes reusable
Functionality built once gets consumed by mobile, partners and internal tools instead of being reimplemented three times.
Technologies we reach for
OpenAPIRESTGraphQLgRPCNode.js.NETJavaGoKongAzure APIMAWS API GatewayOAuth 2.0KeycloakPostmank6
FAQ
Questions we get asked
It depends on the consumer. REST for public and partner APIs where reach and cacheability matter most; GraphQL when a front end needs to assemble data from many sources and you want to stop shipping bespoke endpoints; gRPC for high-volume internal service-to-service calls. Plenty of estates run all three, each where it belongs, behind one gateway.
Additive changes only within a version, contract tests running in CI against recorded consumer expectations, and usage analytics per consumer so we know exactly who still calls a deprecated field. Removal happens after a published deprecation window and direct contact with the remaining callers — never as a surprise in a release note.
Yes. That normally begins with reverse-engineering an accurate specification from the running service, adding contract tests to lock in current behaviour, and only then refactoring behind that safety net. Consumers see no change while the internals are brought up to standard.
Let's talk
Tell us what you are trying to build
Book a free consultation call. You will speak to a senior architect, not a salesperson, and leave with a technical direction and a realistic budget band — before you commit to anything.
- A senior architect on the first call
- A written proposal within 3 business days
- Full IP ownership assigned to you on delivery