Payment gateway for a fintech platform
A high-load payment gateway on Laravel and Go: payment processing with guaranteed idempotency and 99.98% uptime.
- PHP
- Laravel
- Go
- PostgreSQL
- +2
Technology
HTTP API design: resources, versioning, authentication, OpenAPI documentation and stable contracts.
Designing REST APIs is a skill I have been honing for nine years, because it is the API that determines how conveniently and reliably other teams and clients will integrate with the system. I approach an API as a product with a long-lived contract: I design the resource model, use nouns for collections and entities, apply HTTP methods meaningfully (GET for reading, POST for creating, PUT/PATCH for updating, DELETE for deleting) and return correct status codes that reflect the real result of the operation. I pay special attention to predictability: a unified format for responses and errors, machine-readable error codes, clear messages and correct validation handling with per-field detail. To withstand growth I build in versioning from the start so the API can evolve without breaking existing integrations, and I adhere to backward compatibility. Security is a mandatory part: token-based authentication (Sanctum, OAuth2/JWT), authorization of every action on a least-privilege basis, request-rate limiting, validation and sanitization of all input, and protection against typical OWASP threats. For operations that may be repeated I design idempotency through idempotency keys, which is critical for payments and integrations over unreliable networks. I ensure performance and ease of consumption with thoughtful pagination (cursor-based for large sets), filtering, sorting, selective loading of fields and relations, and caching with ETag and Cache-Control headers. I consider documentation part of the contract: I describe the API in an OpenAPI specification, keep it up to date, generate interactive documentation and request examples, which sharply reduces integration cost. I cover every endpoint with integration tests, checking both success scenarios and edge cases and errors. When needed I complement REST with webhooks for event-driven integration and asynchronous processing of long operations. A well-designed REST API, in my understanding, is a stable, documented, secure and predictable interface that serves for years as the foundation for web and mobile clients, partner integrations and internal services.
A high-load payment gateway on Laravel and Go: payment processing with guaranteed idempotency and 99.98% uptime.
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