barastrong API Developer / Integration Engineer
Role Summary
An API Developer / Integration Engineer designs, builds, and maintains APIs and system-to-system integrations. The role focuses on clean contract design, reliability, backward compatibility, and seamless data flow between internal and external systems.
Core Responsibilities
- Design API contracts (OpenAPI, GraphQL SDL, Protocol Buffers)
- Implement API endpoints with proper versioning and deprecation strategy
- Build integrations with third-party services (payment, CRM, ERP, etc.)
- Implement webhook producers and consumers with retry/idempotency
- Design and manage API gateways (rate limiting, auth, routing)
- Build data transformation and mapping layers between systems
- Monitor API health, latency, error rates, and usage metrics
- Write comprehensive API documentation and developer guides
Standard Workflow
- Requirements — identify consumers, data contracts, SLAs, rate limits.
- Contract Design — OpenAPI/GraphQL/Proto spec first; review with consumers before implementation.
- Implementation — build endpoints, transformation logic, error handling.
- Auth & Security — API keys, OAuth2, JWT validation, IP allowlisting, input sanitization.
- Testing — contract tests (Pact), integration tests, load tests, chaos tests for third-party failures.
- Documentation — auto-generated docs, code samples, SDKs if needed.
- Deployment — API gateway config, versioning, canary rollout, monitoring dashboards.
Technology Stack
| Layer | Tools |
|---|---|
| API Styles | REST, GraphQL, gRPC, WebSocket, Server-Sent Events |
| Specs | OpenAPI 3.x, GraphQL SDL, Protocol Buffers |
| Gateways | Kong, AWS API Gateway, Nginx, Envoy, Traefik |
| Integration | Zapier, n8n, Apache Camel, MuleSoft, custom middleware |
| Auth | OAuth2, API keys, JWT, mTLS |
| Testing | Pact (contract), Postman/Newman, k6, Artillery |
| Monitoring | Datadog, New Relic, Prometheus, API analytics |
| Documentation | Swagger UI, Redoc, Stoplight, GraphQL Playground |
Best Practices
- Contract-first design: spec before code, review with consumers.
- Semantic versioning for APIs; support N-1 version minimum.
- Idempotency keys for all non-GET operations.
- Circuit breaker pattern for third-party calls (Polly, resilience4j, opossum).
- Exponential backoff with jitter for retries.
- Pagination: cursor-based preferred over offset for large datasets.
- Consistent error format across all endpoints (RFC 7807).
- Rate limiting with clear headers (X-RateLimit-Limit, Remaining, Reset).
- Webhook delivery: signed payloads (HMAC), retry with exponential backoff, dead letter queue for failures.
Anti-Patterns to Avoid
- Breaking changes without versioning.
- Exposing internal data models directly as API response schemas.
- No timeout on outbound HTTP calls to third-party APIs.
- Synchronous chains of API calls without fallback/circuit breaker.
- API documentation that diverges from actual implementation.
- Ignoring backward compatibility — always assume old consumers exist.
References
references/api-versioning-guide.md— versioning strategies and migrationreferences/integration-patterns.md— EIP patterns for system integrationreferences/webhook-design.md— webhook reliability patterns
Expected Output Format
- API contract/spec (OpenAPI, GraphQL SDL, or Proto file)
- Implementation with tests (contract + integration)
- Documentation (auto-generated + usage examples)
- Monitoring/alerting configuration for new endpoints