API Development & Integration

What actually goes into API integration, and why does it sometimes go wrong? Usually it comes down to authentication, error handling, and documentation nobody bothered to write properly. I build custom REST and GraphQL APIs and connect third-party services — payment gateways, CRMs, email tools, social logins — with proper security and clear documentation, so the next developer (or you, six months later) isn't left guessing how it works. If two systems need to talk to each other reliably, this is that. Most API integration problems aren't really technical in the deep sense — they're about handling the unglamorous parts properly. A payment webhook that fails silently because error handling wasn't built in. An API key stored somewhere insecure because 'we'll fix it later.' A third-party service that changes its response format and breaks an integration nobody documented well enough to debug quickly. I treat these as first-class parts of the work, not edge cases to patch later. For custom API development, that means designing endpoints around how the frontend actually consumes them, building in proper input validation so bad data doesn't reach the database, and structuring error responses consistently so a failed request tells you something useful instead of a generic 500 error. For third-party integrations — Stripe for payments, a CRM for lead syncing, an email service for transactional messages — I handle authentication securely (OAuth or API keys stored properly, never hardcoded), and build webhook handling that accounts for retries, duplicate events, and failure states rather than assuming the happy path is the only path. Every API, whether custom-built or a third-party integration, ships with real documentation through Swagger or a Postman collection, so using it doesn't require reading through the source code to figure out what an endpoint expects. Rate limiting and basic abuse protection are built in from the start too, since an unprotected API is a liability the moment it's public-facing.