Browse Cards
Explore 16 atomic knowledge units

Alerting
introAlerting notifies teams when metrics or logs indicate problems that require attention.

Authentication
introAuthentication verifies that users are who they claim to be, typically through passwords, tokens, or multi-factor methods.

Authorization
introAuthorization determines what actions an authenticated user is permitted to perform within a system.

Blast Radius
introThe blast radius is the scope of impact when something goes wrong. Smaller blast radius means fewer users affected by a failure.

Canary Deployment
intermediateA canary deployment releases changes to a small subset of users first, allowing you to detect issues before full rollout.

Encryption
intermediateEncryption transforms data into an unreadable format that can only be decoded with the correct key.

End-to-End Test
intermediateE2E tests simulate real user workflows through the entire system. They catch integration issues but are slower and more brittle.

Feature Flags
introFeature flags allow you to toggle functionality on or off without deploying new code. They enable gradual rollouts and quick rollbacks.

Input Validation
introInput validation ensures all user-provided data meets expected formats and constraints before processing.

Integration Test
intermediateIntegration tests verify that multiple components work together correctly. They catch issues that unit tests miss.

Logging
introLogging records events and state changes in your application for debugging and auditing purposes.

Metrics
introMetrics are numerical measurements collected over time that help you understand system behavior and performance.

Observability
intermediateObservability is the ability to understand a system's internal state by examining its outputs: logs, metrics, and traces.

Rollback Strategy
intermediateA rollback strategy defines how to quickly revert to a previous working state when a deployment causes issues.

Test Pyramid
introThe test pyramid suggests having many unit tests, fewer integration tests, and even fewer end-to-end tests for optimal coverage and speed.

Unit Test
introUnit tests verify individual functions or components in isolation. They are fast, reliable, and form the foundation of test coverage.