A standalone Express mock server for Supplier API integration testing, allowing suppliers to validate their integrations without AWS access.

1. The server starts from index.js/expressServer.js and loads api/openapi.yaml.
2. Incoming requests are validated against the OpenAPI contract before reaching handlers.
3. Valid requests are routed to controller/service handlers that return canned responses from data/examples/.
4. The sandbox runs on port 9000 by default (configurable in config.js).

• OpenAPI spec: the sandbox uses api/openapi.yaml to enforce request/response contract validation.
• Swagger UI: available at /api-docs/ for interactive endpoint exploration.
• Canned responses: JSON files in data/examples/ provide mock API data.
• Docker: Dockerfile enables containerised deployment for CI or supplier testing environments.

• LetterService.listLetters respects the limit query parameter by truncating the canned response array to simulate pagination.
• This is an OpenAPI Generator-scaffolded project (CommonJS, not TypeScript). It does not share code with the Lambda implementations.
• No authentication is enforced; the authorization behaviour is not simulated.
• The OpenAPI spec in sandbox/api/ may diverge from specification/api/ if not kept in sync during spec updates.

cd sandbox && npm install && npm start

Or via Docker:

docker build -t supplier-api-sandbox sandbox/
docker run -p 9000:9000 supplier-api-sandbox