API development and integration.

An API is a contract. It has to be predictable, versioned, documented, and honest about its failure modes. Most integration pain comes from APIs that were built for one consumer and then reused, or from integrations that assumed the other end would always respond correctly. I build both sides with the awkward cases handled first.

What’s included

• REST and JSON API design, build and documentation
• Authentication: API keys, OAuth, JWT and session-based
• Rate limiting, pagination, filtering and versioning
• Webhook endpoints with signature verification and replay protection
• Third-party integrations with retry, backoff and idempotency
• Reconciliation for integrations that must not lose records
• Sandbox and staging setup for safe consumer testing

Integrations fail; plan for it

The provider will go down, rate limit you, return a 200 with an error body, or send the same webhook twice. An integration that only handles the happy path will lose data silently. I build with idempotency keys, retry with exponential backoff, dead-letter queues for anything that cannot be processed, and a reconciliation path so you can prove nothing was lost.

Webhooks done properly

Receiving a webhook means verifying the signature, responding fast, and processing asynchronously — not doing the work inline and timing out. It also means being ready for duplicates, out-of-order delivery and replays. This is a small amount of extra work at build time and saves a great deal of investigation later.

Documentation as a deliverable

An API nobody can integrate against is not finished. I deliver documentation with real request and response examples, error codes with their meanings, and a sandbox where a consumer can test safely.