API Development
We design and build production APIs — RESTful and GraphQL — that serve as the data layer for web applications, mobile apps, and third-party integrations. Our APIs follow OpenAPI 3.0 specification standards with auto-generated documentation, versioned endpoints, and consistent error response formats. For client projects like Affordable Buses, we built APIs handling booking transactions, fleet availability queries, and payment processing with Stripe integration, all operating under 200ms p95 response times. We implement rate limiting, request validation with Zod or Joi schemas, and structured error codes that frontend teams can programmatically handle. API security includes OAuth 2.0 with PKCE for public clients, API key management for service-to-service communication, and request signing for webhook deliveries. Typical API development projects run 4-8 weeks for a standard CRUD API, or 8-14 weeks for complex transaction-heavy systems.
Design RESTful APIs following OpenAPI 3.0 specification with auto-generated Swagger/Redoc documentation and versioned endpoints (v1, v2) for backward compatibility.
Build GraphQL APIs with Apollo Server or Mercurius, implementing DataLoader for N+1 query prevention, schema stitching, and persisted queries for production performance.
Validate all incoming requests with schema validation (Zod, Joi, Pydantic) and return structured error responses with machine-readable error codes and human-readable messages.
Implement rate limiting (token bucket or sliding window) at 100-10,000 requests per minute per client, with configurable tiers for different API consumers.
Secure APIs with OAuth 2.0 (authorization code with PKCE for SPAs, client credentials for service-to-service), JWT access tokens, and refresh token rotation.
Integrate payment processing APIs (Stripe, Square) with idempotency keys, webhook signature verification, and retry logic for transient failures.
Optimize query performance with database indexing, query plan analysis, and pagination (cursor-based for large datasets, offset-based for smaller collections) targeting sub-200ms p95 response times.
Implement API monitoring with request logging, latency percentile tracking (p50, p95, p99), error rate dashboards, and automated alerts on SLA breaches.
Build webhook delivery systems with retry logic (exponential backoff), delivery status tracking, and request signing (HMAC-SHA256) for receiver verification.
Write comprehensive API test suites: contract tests with Pact, integration tests against test databases, and load tests with k6 validating throughput under expected peak traffic.