API Development & Integration Services for Connected Digital Ecosystems

REST (Representational State Transfer) uses multiple endpoints with fixed data structures, where each endpoint returns a predefined set of data. GraphQL uses a single endpoint where clients specify exactly what data they need using queries. REST is simpler to implement and cache, ideal for straightforward CRUD operations. GraphQL prevents over-fetching and under-fetching, perfect for complex data requirements and mobile apps where bandwidth matters. We recommend REST for simple, cacheable APIs and public APIs; GraphQL for complex data relationships, mobile optimization, and when clients need flexibility. Many modern applications use both: REST for simple operations and GraphQL for complex queries.

We implement comprehensive security measures: Authentication with OAuth 2.0, JWT tokens, or API keys; Authorization with role-based access control (RBAC) and scope-based permissions; HTTPS/TLS encryption for all traffic; Rate limiting to prevent abuse and DDoS attacks; Input validation and sanitization to prevent injection attacks; CORS configuration for browser security; API key rotation and secret management; Request signing for sensitive operations; Audit logging for compliance and forensics. We follow OWASP API Security Top 10 guidelines, conduct regular security audits, implement Web Application Firewall (WAF), and ensure compliance with industry standards (PCI DSS, HIPAA, GDPR).

Timeline varies by complexity: Simple CRUD API (3-5 endpoints) takes 2-3 weeks; Medium complexity API (10-15 endpoints with authentication) takes 4-6 weeks; Complex API with multiple integrations and advanced features takes 8-12 weeks; Enterprise API platform with multiple services takes 3-6 months. Timeline includes design, development, testing, documentation, and deployment. GraphQL APIs typically take 20-30% longer due to schema design complexity. Third-party integrations add 1-2 weeks per platform. We follow agile methodology with 2-week sprints, delivering working API incrementally for early feedback and testing.

API versioning manages changes to your API while maintaining backward compatibility with existing clients. It's critical because: Prevents breaking existing integrations when you update the API; Allows gradual client migration to new versions; Enables testing new features without affecting production users; Supports multiple client versions simultaneously. We implement versioning through: URL versioning (api.example.com/v1/users), header versioning (Accept: application/vnd.api+json; version=1), or query parameter versioning. Best practice: maintain at least 2 versions, provide deprecation notices 6+ months in advance, document breaking changes clearly, and offer migration guides for upgrading.

Our integration process: API discovery and documentation review to understand capabilities and limitations; Authentication setup (OAuth, API keys) with secure credential management; SDK evaluation or custom wrapper development for easier usage; Error handling with exponential backoff and circuit breakers for resilience; Rate limit compliance to stay within API quotas; Webhook setup for real-time event notifications; Data transformation and mapping between systems; Comprehensive testing in sandbox environments; Production monitoring and alerting. We handle common challenges: rate limiting, authentication token refresh, webhook signature verification, API versioning, pagination, and data synchronization. We also implement fallback mechanisms for API outages.

An API gateway is a server that acts as a single entry point for all client requests, routing them to appropriate backend services. It provides: Authentication and authorization; Rate limiting and throttling; Request/response transformation; Load balancing; Caching; Analytics and monitoring; API versioning. You need an API gateway when: You have microservices architecture; You need centralized security and monitoring; You want to expose internal services externally; You require rate limiting and quotas; You need to aggregate multiple service calls. For simple applications with few endpoints, a gateway may be overkill. We implement gateways using Kong, AWS API Gateway, Azure API Management, or Apigee depending on your infrastructure and requirements.

Performance optimization strategies: Caching with Redis or CDN for frequently accessed data; Database query optimization with proper indexing and query tuning; Pagination for large datasets (limit results to 20-100 per request); Data compression (gzip/brotli) to reduce payload size; Async processing for long-running operations; Connection pooling to database and external services; Response field filtering (sparse fieldsets) to send only requested data; HTTP/2 for multiplexing and header compression; CDN for static content and global distribution. We monitor API performance with metrics: response time (target < 100ms for simple operations), throughput (requests per second), error rate (target < 0.1%), and 99th percentile latency. Regular load testing ensures performance under high traffic.

Webhooks are HTTP callbacks that notify your application when events occur in external systems, enabling real-time integration without polling. Use webhooks for: Real-time notifications (payment confirmations, order status); Event-driven workflows (user signup triggers email); Data synchronization between systems; Reducing API polling overhead. Implementation includes: Webhook endpoint creation to receive events; Signature verification for security (HMAC); Idempotency handling for duplicate events; Retry logic for failed deliveries; Event logging and monitoring. Challenges we handle: Security (verify webhook sources), reliability (implement retry and deduplication), debugging (comprehensive logging), and scaling (handle burst traffic). Alternative: Server-Sent Events (SSE) for one-way server-to-client updates.

Comprehensive API documentation includes: OpenAPI/Swagger specification for interactive documentation; Getting started guide with authentication setup; Complete endpoint reference with request/response examples; Authentication and authorization guide; Error codes and troubleshooting; Rate limits and quotas; Webhooks documentation; SDKs and code samples in multiple languages; Changelog and versioning information; Postman collection for testing. We use tools like Swagger UI, Redoc, or custom developer portals. Documentation is: Auto-generated from code annotations to stay in sync; Interactive with 'Try it out' functionality; Searchable and well-organized; Version-specific; Regularly updated. Good documentation reduces integration time by 60-80% and support requests significantly.

Comprehensive monitoring strategy: Real-time metrics (response time, throughput, error rate) with dashboards; Uptime monitoring with health checks every 1-5 minutes; Distributed tracing for request flow across services; Error tracking with stack traces and context; Performance profiling to identify bottlenecks; Usage analytics (endpoints, clients, traffic patterns); Alerting for anomalies and SLA breaches. We use tools like Datadog, New Relic, Prometheus, or CloudWatch. Maintenance includes: Regular performance optimization; Security patches and dependency updates; API version management; Capacity planning based on growth; Documentation updates; Bug fixes and feature enhancements. We provide SLA-backed support with guaranteed response times and uptime guarantees (99.9%+).