API Development

An API is a contract, and the cost of getting it wrong is paid by everyone who integrates against it — usually for years. Versioning, error semantics, pagination and authentication are decisions that look small during the build and become extremely expensive to revisit once external consumers depend on them.

What this covers

APIs designed as long-lived contracts, documented well enough that integrators do not need to contact you.

• REST and GraphQL API design
• Authentication, scopes and rate limiting
• Versioning and deprecation strategy
• Documentation and developer experience
• Webhooks and event delivery
• Monitoring, logging and usage analytics
• SDK and client library development

Where APIs usually go wrong

No versioning strategy. The first breaking change arrives eventually. Without a version scheme agreed up front, you choose between breaking your integrators and never changing anything.

Inconsistent error handling. Different endpoints returning different error shapes forces every consumer to write defensive special cases, and makes your support burden permanent.

Documentation as an afterthought. An undocumented API generates support tickets indefinitely. Documentation is cheaper than the tickets by a wide margin.

Leaking internal structure. Endpoints that mirror your database schema tie your public contract to your internal refactors, so you can never safely change either.

How we build it

1. Contract design. Resources, operations, error semantics and authentication model agreed and written down before implementation begins.
2. Specification first. An OpenAPI or GraphQL schema your consumers can review and build against while the implementation is still in progress.
3. Implementation and testing. Build against the specification, with contract tests preventing accidental breaking changes.
4. Documentation and launch. Reference docs, worked examples and a sandbox, plus monitoring on usage and error rates from day one.

Technologies we work with

• Backend: Node.js, Python, Go, PHP
• Specification: OpenAPI, GraphQL, JSON Schema
• Authentication: OAuth 2.0, JWT, API keys, mTLS
• Infrastructure: API gateways, Redis, message queues
• Tooling: Postman, contract testing, automated docs

What you get

• A documented, versioned API contract
• Published reference documentation with examples
• Contract tests guarding against breaking changes
• Monitoring on usage, latency and error rates
• Source code and infrastructure you own

Frequently asked questions

REST or GraphQL?

It depends on your consumers. REST suits stable resource-shaped data and is easier for third parties to adopt. GraphQL suits clients with varied and changing data needs, particularly your own applications. Sometimes the right answer is both, for different audiences.

Can you document an API we already have?

Yes. We can generate a specification from an existing implementation, document it properly, and flag the inconsistencies that will cause integrator problems later.

How do you handle breaking changes?

With a versioning scheme and a deprecation policy agreed before launch — advance notice, an overlap period where both versions run, and monitoring so you can see who is still on the old version before you retire it.

Do you build client SDKs?

Yes, where they earn their keep. For most APIs, generated clients from a good specification are sufficient and far cheaper to maintain than handwritten SDKs.

How we start

Every engagement starts with a short, fixed-scope conversation. You leave with a plan and a price whether or not you continue with us.