Express Api Development

Trigger Boundary

• •Use when building or modifying Express-based HTTP APIs.
• •Do not use for framework-agnostic API policy only; use api-design-rest.
• •Do not use for infrastructure deployment tasks.

Goal

Build maintainable Express APIs with explicit middleware chain and reliable error semantics.

Inputs

• •Endpoint requirements and validation rules
• •AuthN/AuthZ and rate-limit requirements
• •Logging and observability expectations

Outputs

• •Route and middleware composition plan
• •Request validation and error response strategy
• •Operational checklist for logging and health endpoints

Workflow

1. •Define route modules by domain and resource responsibility.
2. •Add validation middleware before business logic handlers.
3. •Centralize error handling with consistent response shapes.
4. •Wire auth, rate limiting, and request correlation IDs.
5. •Validate critical paths with integration-level API tests.

Quality Gates

• •Middleware order is deterministic and documented.
• •Validation failures return clear client-actionable responses.
• •Error handling avoids unhandled promise or silent failures.
• •Logs and metrics are sufficient for incident triage.

Failure Handling

• •Stop when middleware side effects are order-dependent and unclear.
• •Escalate when error contracts diverge across endpoints.