Unit 1 of 3

REST API Fundamentals

18 min +200 points

Learning objectives

When you finish this unit, you will be able to:

  • Construct a REST API request to accomplish a task given API documentation.
  • Explain common HTTP response codes associated with REST APIs.
  • Troubleshoot a problem given the HTTP response code, request and API documentation.
  • Identify the parts of an HTTP response (response code, headers, body).
  • Utilize common API authentication mechanisms: basic, custom token, and API keys.

REST API essentials

Constructing requests

Given API documentation, build REST requests with the correct HTTP method, endpoint, headers, and body to accomplish a task.

HTTP response codes

Know common codes such as 200 (OK), 201 (Created), 400 (Bad Request), 401 (Unauthorized), 403 (Forbidden), 404 (Not Found), and 500 (Server Error).

Response structure

An HTTP response includes:

  • Status code: indicates success or failure type.
  • Headers: metadata (content type, auth tokens, etc.).
  • Body: payload (often JSON).

Authentication

  • Basic auth: username and password encoded in headers.
  • Custom token: bearer or session tokens.
  • API keys: key passed in header or query parameter.

Exam focus: construct requests, interpret responses, and troubleshoot using status codes and documentation.

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