API Crash Course: How to Create, Test, & Document your APIs

Explore how web applications run in a browser, using client-server architecture with front end and back end, communicating via HTTP to display data and submit forms.

Understand the anatomy of http requests and responses, including the request line, headers, and body, plus status lines and headers that convey the content type and status codes.

Postman, the api platform, lets you create a new http request and send a simple get request to google.com to see the request, response, headers, body, and status 200.

Explore HTTP methods by applying get, post, put, and patch to APIs, covering CRUD operations—create, read, update, delete—and the importance of authorization and authentication.

Identify common http status codes, including 200, 201, 400, 401, 403, 404, and 500, and relate them to create, read, update, delete operations.

Explore how an API enables applications to communicate through an intermediary endpoint, offering abstraction and consistent access to data and features.

Explore the main types of APIs, including local, web, library, and hardware, and focus on web APIs for data retrieval, data submission, and service integration.

Learn SOAP APIs as a protocol-based web API architecture that uses XML envelopes, mandatory POST requests, and a header and body structure, emphasizing security and strict standards.

Explore REST as the popular architectural style for APIs, contrasting it with SOAP, and learn how stateless HTTP methods (get, post, put, delete) exchange JSON data for CRUD operations.

Explore XML data, an extensible markup language using tags and nested elements to store and transport data, and compare its syntax and readability to JSON for APIs and config.

Clarify authentication and authorization in API security, showing how credentials verify identity and permissions regulate access to resources. See how roles determine allowed actions like read, update, and delete.

Clarify the difference between encoding and encryption, then compare how encoding enables safe transmission and compatibility, while encryption secures data with a key against unauthorized access.

Learn how api keys authenticate client requests, pass in headers, query parameters, or the body, and secure handling and rotation to prevent unauthorized access.

Discover how bearer authentication, including parallel authentication, extends simple API keys with a token in the authorization header, using JWTs to securely access APIs and manage token expiration and renewal.

Create APIs using Mocky to generate free, customizable mock responses and test frontend and backend interactions, with mocks available forever if called at least once per year.

Learn how to create and run API tests in Postman, automate test generation with postbot, and validate status codes, response time, and JSON schema.

Explore 1xx informational status codes like 100 continue and 101 switching protocols as client-server negotiations, and learn how 200 ok and 417 influence large file uploads.

Explain how the 101 switching protocols code indicates a successful upgrade via the upgrade header, enabling HTTP to HTTPS or HTTP/1.1 to HTTP/2, and note rare use of informational codes.

Explain the 3xx redirection class, focusing on 300 indicating further action, and how 301 and 302 redirects move to new URLs via the location header.

Analyze 302 found, 303 see others, and 304 not modified, and explain when to use 307/308; describe the location header redirects and why to avoid unnecessary downloads.

Demonstrate 305 use proxy and 306 unused, then compare 307 and 308 redirects. Explain how the location header guides future requests and how 308 aligns with 301 permanently.

Explore 4xx client side errors, including bad request, unauthorized, not found, and the rarely used 402 payment required, and learn how faulty requests and authentication cause them.

Discover why API documentation is essential for everyday APIs, learn how OpenAPI and Swagger automate documentation, and grasp the lifecycle and version updates that keep APIs usable.

Explore the swagger editor with the petstore sample, learn how to convert swagger to OpenAPI, and work with YAML or JSON while configuring servers, tags, and indentation.

Learn Swagger practical API documentation by detailing tags, descriptions, and path parameters, documenting put and delete methods with request bodies and reusable components for monitor connections and profiles.

Compare Put and Patch methods to decide when to replace the entire resource with Put versus applying a partial update with Patch, especially when resources contain many fields.