PHP Laravel 5 API Authentication Optimization

Our PHP 7 application runs on Laravel 5 and exposes several REST-style endpoints. Lately the authentication layer has been our main pain-point: spikes of 401/403 responses, inconsistent token validation, and occasional session time-outs are inflating the overall error rate. I need you to dive into the existing controller and middleware code, trace the root causes, and re-work the relevant functions so the API returns clean, predictable results.

Core focus
• Reduce authentication-related errors without altering functional behaviour.
• Keep all updates compatible with PHP 7 and the current Laravel 5 codebase.

I will grant access to the Git repository and recent log samples so you can profile the affected routes, adjust middleware, tighten validation rules, and—where sensible—introduce caching or queue-based throttling. Automated tests already cover the main endpoints; please extend them to confirm the new, lower error rate and document any config changes needed for staging/production.

Deliverables
1. Refactored authentication logic (controllers, middleware, helpers) committed via pull request.
2. Updated unit/feature tests proving the reduction in error rate.
3. Concise changelog and roll-back notes.

Acceptance criteria
– 95 % drop in authentication-related errors measured over 48 h on staging.
– No breaking changes to existing public endpoints.
– All tests passing in the current CI pipeline.

Feel free to suggest additional best-practice tweaks if you spot opportunities while working through the code.