Custom API Development & Integration

Expert API Development & Integration Services

APIs are the backbone of modern software. Whether you need a custom REST API to power your mobile app, a payment integration to process transactions, or a webhook system to synchronize data across platforms, I build APIs that are secure, performant, and a pleasure for developers to work with.

With over ten years of experience building APIs for startups and enterprises alike, I understand that a great API is more than just working endpoints. It requires thoughtful resource design, consistent error handling, proper versioning, and documentation that developers actually want to read. Every API I deliver follows REST best practices and comes with interactive Swagger/OpenAPI documentation out of the box.

REST API Architecture & Design

I design RESTful APIs with clean resource hierarchies, proper HTTP method usage, consistent response formats, and HATEOAS links where appropriate. Pagination, filtering, sorting, and field selection are built in from the start so your API consumers get exactly the data they need without over-fetching. I follow JSON:API or custom response envelope standards based on your team's preferences and existing conventions.

Authentication & Security

Security is not an afterthought. I implement OAuth 2.0 authorization flows, JWT-based stateless authentication, API key management, and role-based access control tailored to your application. Every API includes HTTPS enforcement, input validation, SQL injection prevention, rate limiting, and CORS configuration. For sensitive operations, I add request signing, IP whitelisting, and audit logging.

Payment & Third-Party Integrations

I integrate APIs from leading platforms including Stripe, PayPal, Braintree, Twilio, SendGrid, Salesforce, HubSpot, QuickBooks, and many more. Each integration includes proper error handling, webhook processing, retry logic, and idempotency to ensure reliable data flow between systems. I handle the complexities of OAuth handshakes, token refresh, rate limit management, and data transformation so your application works seamlessly with external services.

Webhook Development & Event Systems

I build robust webhook systems for both sending and receiving events. Outgoing webhooks include signature verification, retry policies with exponential backoff, and delivery tracking. Incoming webhook handlers validate payloads, process events idempotently, and queue background jobs for heavy processing. This ensures your integrations stay in sync without polling or manual intervention.

API Documentation & Developer Experience

Every API I build includes interactive documentation generated from OpenAPI/Swagger specifications. Documentation covers authentication setup, endpoint descriptions, request/response schemas, error codes, and runnable code examples. I also create Postman collections for easy testing and provide SDK scaffolding when needed. Great documentation reduces integration time for your team and partners from days to hours.

Technology Stack

Why Hire Me for API Development

You work directly with a senior engineer who has built APIs handling millions of requests across e-commerce, travel, SaaS, and fintech domains. No junior handoffs, no agency overhead. I bring deep experience in rate limiting strategies, API versioning, caching architectures, and the real-world edge cases that only come from years of production API development. Whether you need a new API from scratch or need to fix and document an existing one, I deliver clean, reliable, and well-documented solutions.