Pattern Playground

Watch the LRU (Least Recently Used) cache in action. See how entries are stored, accessed, and evicted when the cache reaches capacity.

See how Zod validates API requests in real-time. Try submitting valid and invalid data to see the validation errors.

Experience rate limiting firsthand. Click the button rapidly to see how the sliding window algorithm blocks excess requests.

See how custom error classes and error boundaries work together. Trigger different errors to see the consistent error responses.

Experience structured logging with Pino. Watch logs stream in real-time with different levels and see automatic redaction of sensitive data.

See how Zod validates environment variables at startup. Invalid or missing variables are caught immediately, not in production.

Manage user sessions with device tracking and automatic expiration. See active sessions across devices and revoke access.