# Unkey Glossary Clear definitions for API and platform terms. Source: https://unkey.com/glossary Append `.md` to any glossary term URL to receive the raw markdown source. --- - [API Caching](https://unkey.com/glossary/api-caching) ([Markdown](https://unkey.com/glossary/api-caching.md)) — Unlock API performance with caching. Learn best practices and examples in Java, C++, Python, C#. Explore REST API caching strategies. - [API Circuit Breaker](https://unkey.com/glossary/api-circuit-breaker) ([Markdown](https://unkey.com/glossary/api-circuit-breaker.md)) — Unlock API Circuit Breakers power. Learn from implementation examples. Explore Spring Boot and API Gateway integration. - [API Documentation-Driven Design](https://unkey.com/glossary/api-documentation-driven-design) ([Markdown](https://unkey.com/glossary/api-documentation-driven-design.md)) — Master API Documentation-Driven Design. Learn principles, create templates, explore RESTful API patterns. Start now. - [API Load Balancing](https://unkey.com/glossary/load-balancing) ([Markdown](https://unkey.com/glossary/load-balancing.md)) — Unlock API Load Balancing power. Learn API Gateway, Load Balancer architecture, microservices, best practices. Start now. - [API Mock Server](https://unkey.com/glossary/api-mock-server) ([Markdown](https://unkey.com/glossary/api-mock-server.md)) — Discover API Mock Servers. Learn essentials, key takeaways from popular tools to best practices. Dive into Postman Mock Server. - [Backend For Frontend](https://unkey.com/glossary/backend-for-frontend) ([Markdown](https://unkey.com/glossary/backend-for-frontend.md)) — Unlock Backend For Frontend (BFF) potential. Learn essentials, key takeaways from real-world implementations. Explore BFF vs API Gateway. - [Backward Compatibility](https://unkey.com/glossary/backward-compatibility) ([Markdown](https://unkey.com/glossary/backward-compatibility.md)) — Unlock the power of API backward compatibility. Learn essentials and key takeaways for maintaining backward compatibility in microservices. Dive in! - [Containerization](https://unkey.com/glossary/containerization) ([Markdown](https://unkey.com/glossary/containerization.md)) — Discover containerization power. Learn essentials from real-world examples. Understand vs virtualization. Dive in. - [CORS](https://unkey.com/glossary/cors) ([Markdown](https://unkey.com/glossary/cors.md)) — Unlock the power of CORS in API development. Learn essentials and key takeaways from expert examples. Dive into CORS API Gateway. Start now. - [Distributed Tracing](https://unkey.com/glossary/distributed-tracing) ([Markdown](https://unkey.com/glossary/distributed-tracing.md)) — Master distributed tracing for microservices with expert insights. Learn key benefits, best practices, and popular tools for effective tracing. Start now - [Governance](https://unkey.com/glossary/governance) ([Markdown](https://unkey.com/glossary/governance.md)) — Master API governance essentials with expert insights. Learn core principles and best practices for effective API management and compliance. Start now. - [HATEOAS](https://unkey.com/glossary/hateoas) ([Markdown](https://unkey.com/glossary/hateoas.md)) — Grasp HATEOAS principles with real-world examples. Learn essentials of implementing HATEOAS with Spring Boot and on GitHub. Dive in today. - [horizontal scaling](https://unkey.com/glossary/horizontal-scaling) ([Markdown](https://unkey.com/glossary/horizontal-scaling.md)) — Master horizontal scaling essentials with expert insights. Learn key benefits and best practices for effective software architecture. Start now. - [Idempotency](https://unkey.com/glossary/idempotency) ([Markdown](https://unkey.com/glossary/idempotency.md)) — Understand idempotency in API development. Learn key characteristics, real-world applications, and why PUT is idempotent while POST is not. Dive in now. - [JWT](https://unkey.com/glossary/jwt) ([Markdown](https://unkey.com/glossary/jwt.md)) — Unlock JWT power for API development. Learn essentials, key takeaways with practical examples. Master JWT authentication. - [Keep-Alive](https://unkey.com/glossary/keep-alive) ([Markdown](https://unkey.com/glossary/keep-alive.md)) — Master Keep-Alive concepts to enhance API performance. Learn key mechanisms and best practices for efficient connection management. Start now. - [Long Polling](https://unkey.com/glossary/long-polling) ([Markdown](https://unkey.com/glossary/long-polling.md)) — Master long polling fundamentals with expert insights. Learn core mechanics and best practices for effective web application communication. Start now. - [MIME types](https://unkey.com/glossary/mime-types) ([Markdown](https://unkey.com/glossary/mime-types.md)) — Unlock MIME Types world. Learn from API development examples. Dive into image/video MIME types. Start now. - [OpenAPI](https://unkey.com/glossary/openapi) ([Markdown](https://unkey.com/glossary/openapi.md)) — Unlock OpenAPI power. Learn essentials, evolution to implementation. Discover tools, best practices. Dive in. - [RESTful API](https://unkey.com/glossary/restful-api) ([Markdown](https://unkey.com/glossary/restful-api.md)) — Unlock RESTful API design power. Learn essentials from experts. Master design patterns and naming conventions. - [RESTful API Modeling Language](https://unkey.com/glossary/restful-api-modeling-language) ([Markdown](https://unkey.com/glossary/restful-api-modeling-language.md)) — Master RESTful API Modeling Language essentials with expert guidance. Learn core features and best practices for effective API development. Start now. - [SDK](https://unkey.com/glossary/sdk) ([Markdown](https://unkey.com/glossary/sdk.md)) — Understand SDKs in API development. Learn key differences between SDK and API, with real-world examples. Dive into SDK vs REST API pros and cons. Start today. - [Secure Sockets Layer](https://unkey.com/glossary/secure-sockets-layer) ([Markdown](https://unkey.com/glossary/secure-sockets-layer.md)) — Unlock API security with SSL. Learn essentials of SSL architecture and certificate implementation. Dive into SSL vs TLS. Start mastering. - [Single Sign On](https://unkey.com/glossary/single-sign-on) ([Markdown](https://unkey.com/glossary/single-sign-on.md)) — Unlock SSO benefits in API development. Learn essentials from AWS SSO API examples. Master REST API SSO authentication. - [Statelessness](https://unkey.com/glossary/statelessness) ([Markdown](https://unkey.com/glossary/statelessness.md)) — Understand statelessness in APIs. Learn differences between stateless and stateful APIs, with examples. Explore REST API design. - [transport-layer-security](https://unkey.com/glossary/transport-layer-security) ([Markdown](https://unkey.com/glossary/transport-layer-security.md)) — Unlock TLS in API. Learn how it works, its differences with SSL, HTTPS. Dive in now. - [vertical scaling](https://unkey.com/glossary/vertical-scaling) ([Markdown](https://unkey.com/glossary/vertical-scaling.md)) — Master vertical scaling concepts with expert insights. Learn key differences between vertical and horizontal scaling in cloud computing. Start now - [Webhook](https://unkey.com/glossary/webhook) ([Markdown](https://unkey.com/glossary/webhook.md)) — Understand Webhooks in API development. Learn differences, creation steps, real-world examples. Explore Webhooks vs WebSockets. - [X-Forwarded-For](https://unkey.com/glossary/x-forwarded-for) ([Markdown](https://unkey.com/glossary/x-forwarded-for.md)) — Understand the X-Forwarded-For header and its importance in API development. Learn key use cases and best practices for security and validation. Start now. - [Zero-Downtime API Deployment](https://unkey.com/glossary/zero-downtime-api-deployment) ([Markdown](https://unkey.com/glossary/zero-downtime-api-deployment.md)) — Achieve seamless API updates with zero-downtime deployment. Learn key strategies and best practices. Explore Kubernetes, AWS, and Docker deployments. Dive in!