API Quick Reference | Cheat Sheet | Documentation | Overview

An Application Programming Interface (API) is a set of rules and protocols that allows two software applications to communicate and exchange data. It acts as a middleman, handling requests and responses between a client and a server. To understand and use an API effectively, you need to know some API Reference:

 

HTTP Verbs

• GET: Retrieve data from the server
• POST: Send data to the server to create a resource
• PUT: Send data to the server to update a resource
• PATCH: Send data to the server to update a resource partially
• DELETE: Delete a resource from the server
• TRACE: Returns the full HTTP request received by the server for debugging and diagnostic purposes
• OPTIONS: Returns the HTTP methods supported by the server for the requested URL
• CONNECT: Converts the request connection to a transparent TCP/IP tunnel for secure communication
• PURGE: Invalidates a cached resource
• LOCK: Locks the resource for exclusive use by the client
• UNLOCK: Unlocks the resource previously locked by the client
• MKCOL: Creates a new collection resource
• COPY: Copies the resource identified by the Request-URI to the destination URI.

HTTP Status Codes

• 1xx: Informational
• 2xx: Success
• 3xx: Redirection
• 4xx: Client Errors
• 5xx: Server Errors

Response Headers

• Content-Type: Specifies the MIME type of the data in the response body
• Content-Length: Specifies the length of the response body in bytes
• Cache-Control: Specifies the caching behavior of the response
• Location: Specifies the URI of a resource that can be used to retrieve the requested resource
• Server: Specifies the name and version of the server software that generated the response
• Access-Control-Allow-Origin: Specifies which origins are allowed to access the resource
• Set-Cookie: Specifies a cookie that should be stored by the client and sent back to the server with future requests
• Expires: Specifies the date and time after which the response is considered stale
• Last-Modified: Specifies the date and time the resource was last modified.

API Design

• REST: Representational State Transfer, a design pattern for building web services
• SOAP: Simple Object Access Protocol, a messaging protocol for exchanging structured data
• GraphQL: A query language and runtime for building APIs
• API Gateway: A service that manages, protects, and scales APIs

API Architectures

• SOA: Service-Oriented Architecture, an architectural style for building distributed systems
• Microservices: An architectural style for building complex applications as a suite of small, independent services
• Serverless: A cloud computing execution model where the cloud provider manages the infrastructure and automatically allocates resources as needed
• Event-Driven: An architectural style where the flow of data between components is triggered by events
• RESTful API: An architectural style that uses HTTP requests to GET, POST, PUT, and DELETE data.

API Design Patterns

• Adapter Pattern: A pattern that converts the interface of a class into another interface that clients expect
• Decorator Pattern: A pattern that adds behavior to an individual object dynamically
• Proxy Pattern: A pattern that provides a surrogate or placeholder for another object to control access to it
• Chain of Responsibility Pattern: A pattern that delegates commands to a chain of processing objects
• Observer Pattern: A pattern that defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

API Security

• OAuth: An open standard for authorization used for protecting APIs
• JWT: JSON Web Tokens, a standard for securely transmitting information between parties as a JSON object
• SSL/TLS: Secure Sockets Layer/Transport Layer Security, a protocol for establishing a secure connection between a client and a server
• API Key: A secret token used to authenticate API requests
• Rate Limiting: A technique used to limit the number of requests that can be made to an API over a specific period of time
• OpenID Connect: An authentication layer built on top of OAuth that allows users to be authenticated across multiple domains
• Cross-Origin Resource Sharing (CORS): A mechanism that allows many resources (e.g., fonts, JavaScript, etc.) on a web page to be requested from another domain outside the domain from which the resource originated

API Testing

• Postman: A popular tool for testing and debugging APIs
• SoapUI: A tool for testing SOAP and REST web services
• Swagger: A tool for designing, building, and testing APIs
• JMeter: A tool for testing the performance of APIs
• TestRail: A test management tool for planning, executing, and tracking API tests
• Dredd: A command-line tool for testing API documentation against its backend implementation
• REST Assured: A Java-based library for testing RESTful APIs
• Karate DSL: A testing framework for API testing using Gherkin syntax
• HttpMaster: A tool for testing and debugging APIs
• Assertible: A tool for testing and monitoring APIs with automated tests.

API Development

• Node.js: A JavaScript runtime for building server-side applications
• Express: A popular framework for building web applications and APIs with Node.js
• Django: A Python web framework for building web applications and APIs
• Flask: A lightweight Python web framework for building web applications and APIs
• Spring: A Java framework for building enterprise-level web applications and APIs
• Swagger Editor: A tool for designing and documenting APIs using the OpenAPI specification
• Postman: A tool for testing and debugging APIs
• Insomnia: A tool for designing, testing, and debugging APIs
• Paw: A tool for designing and testing APIs on Mac OS
• API Blueprint: A high-level API description language for building RESTful APIs.

API Implementation Platforms

• Firebase: A mobile and web application development platform developed by Google
• Backendless: A mobile and web application development platform that allows developers to build and deploy applications without backend coding
• Parse Server: An open-source version of the Parse backend that can be deployed to any infrastructure
• Amazon API Gateway: A fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure APIs
• Microsoft Azure API Management: A fully managed service that enables users to publish, secure, transform, maintain, and monitor APIs.

API Performance

• Caching: A technique for improving API performance by storing responses in a cache
• Throttling: A technique for limiting the rate of requests to an API to prevent overload
• Load Balancing: A technique for distributing traffic evenly across multiple servers to improve API performance
• Content Delivery Network (CDN): A distributed system of servers that delivers content to users based on their geographic location to improve API performance
• Edge Computing: A computing paradigm that brings computation and data storage closer to the location where it is needed to reduce latency and improve API performance.

API Monitoring

• Pingdom: A tool for monitoring the uptime and performance of APIs
• New Relic: A tool for monitoring the performance of APIs and other web applications
• Datadog: A monitoring and analytics platform for cloud-scale applications and APIs
• Sumo Logic: A cloud-based log management and analytics platform for APIs and other applications
• Loggly: A cloud-based log management platform for monitoring APIs and other applications

API Standards

• JSON API: A specification for building APIs that use JSON as the data format
• HAL: Hypertext Application Language, a standard for building hypermedia-driven APIs
• JSON-LD: A format for representing linked data on the web
• OData: Open Data Protocol, a standard for building and consuming RESTful APIs
• AsyncAPI: A specification for building event-driven APIs.

API Standards Organizations

• W3C: The World Wide Web Consortium, an international community that develops web standards
• IETF: The Internet Engineering Task Force, an open standards organization that develops and promotes Internet standards
• OASIS: Organization for the Advancement of Structured Information Standards, a nonprofit consortium that drives the development, convergence, and adoption of open standards for the global information society
• RESTful API Modeling Language (RAML): A YAML-based language for describing RESTful APIs developed by MuleSoft
• JSON API: A specification for building APIs that use JSON as the data format.

API Infrastructure

• Kubernetes: An open-source platform for managing containerized workloads and services
• OpenShift: A container application platform that builds on top of Kubernetes
• Docker Swarm: A native clustering and orchestration solution for Docker
• Consul: A service mesh solution that provides service discovery, configuration, and segmentation capabilities
• Istio: A service mesh solution that provides traffic management, security, and observability capabilities.

API Governance

• API Management: The process of creating, publishing, and monitoring APIs in a secure and scalable way
• API Monetization: The process of generating revenue from APIs by charging developers for usage
• API Versioning: The process of managing changes to APIs over time
• API Analytics: The process of collecting and analyzing data on API usage and performance
• API Gateway: A service that manages, protects, and scales APIs.

API Documentation

• OpenAPI: A specification for building APIs in YAML or JSON format
• API Blueprint: A high-level API description language for building RESTful APIs
• RAML: A YAML-based language for describing RESTful APIs
• Swagger UI: A tool for visualizing and interacting with APIs that have been described using the OpenAPI specification
• Slate: A tool for generating beautiful, responsive API documentation.

API Deployment

• Heroku: A cloud platform for deploying, managing, and scaling web applications and APIs
• AWS Elastic Beanstalk: A service for deploying and scaling web applications and APIs on AWS
• Azure App Service: A service for deploying and scaling web applications and APIs on Azure
• Google App Engine: A service for deploying and scaling web applications and APIs on GCP
• Docker: A containerization platform used for packaging and deploying applications
• AWS Lambda: A serverless compute service for running code in response to events
• Azure Functions: A serverless compute service for running code in response to events
• Google Cloud Functions: A serverless compute service for running code in response to events
• Netlify: A cloud platform for deploying and managing static websites and APIs
• Vercel: A cloud platform for deploying and managing static websites and APIs

API Security

• OAuth: An open standard for authorization used by many social media platforms and APIs
• OpenID Connect: An authentication layer built on top of OAuth that allows users to be authenticated across multiple domains
• JSON Web Tokens (JWT): A method for representing claims securely between two parties
• Cross-Origin Resource Sharing (CORS): A mechanism that allows many resources (e.g., fonts, JavaScript, etc.) on a web page to be requested from another domain outside the domain from which the resource originated
• API Keys: A secret token that identifies an API client to the server and allows the client to access resources.

API Best Practices

• Versioning: A technique for managing changes to APIs over time
• Pagination: A technique for breaking up large API responses into smaller, more manageable chunks
• Caching: A technique for improving API performance by storing responses in a cache
• Error Handling: A technique for returning meaningful error messages to API clients
• HATEOAS: Hypermedia as the Engine of Application State, a constraint of RESTful APIs that requires the API to provide links to related resources

API Tutorials

• Getting Started with RESTful APIs by Tania Rascia
• API Design Best Practices by Martin Fowler
• Testing RESTful Web Services Made Easy Using the REST Assured Framework by Dinesh Rajput
• API Gateway Concepts and Options by AWS
• Building Secure APIs by Auth0
• RESTful API Designing guidelines — The best practices by Mahesh Haldar

API Guides (Reference)

• REST API Tutorial by Guru99
• A Beginner’s Guide to HTTP and REST by Linode
• REST API Design: Resource Modeling by Oracle
• API Security Best Practices by Google Cloud
• API Governance Handbook by WSO2.

API Tools 

• API Studio: A web-based IDE for designing and testing APIs
• Stoplight: A collaborative platform for designing, documenting, and testing APIs
• Apigee: A full lifecycle API management platform that allows developers to design, secure, deploy, and analyze APIs
• Azure API Management: A fully managed service that enables users to publish, secure, transform, maintain, and monitor APIs
• Postman Learning Center: A hub for learning how to use Postman to design, develop, and test APIs.