Backend: Add API-level caching for read endpoints with ETag and If-None-Match

[greatest0fallt1me]

Description

Add ETag support for read-heavy endpoints (credit line summary, transactions) so clients can avoid full payload downloads when data hasn’t changed.

Requirements and context

• Must be secure, tested, and documented.
• Must ensure ETag changes when underlying state changes.

Suggested execution

git checkout -b feature/etag-caching

Implement changes

• Add ETag generator for responses.
• Add conditional request handling returning 304.
• Integration tests for ETag/304 behavior.
• Document caching semantics.

Test and commit

npm test

Example commit message

feat(perf): ETag caching for read-heavy endpoints

Guidelines

• Timeframe: 96 hours.