Accessing OAuth 2.0 Protected APIs
OAuth 2.0 is an authorization framework that allows users to grant third-party applications permission to access services on their behalf, eliminating the need for repetitive credential entry while ensuring security and flexibility.This guide demonstrates how to debug OAuth 2.0 APIs using Apidog, with Google account sign-in as a practical example.Understanding the OAuth 2.0 Flow#
In a typical OAuth 2.0 scenario:Client: Your website or application
Authorization Server: The service providing authentication (e.g., Google)
Resource Server: The service hosting protected resources
Prerequisites#
Before testing OAuth 2.0 APIs, ensure you have:An OAuth client registered with the authorization server (e.g., Google API Console Project)
Client ID and client secret credentials
If you haven't registered a Google API Console Project, refer to the official documentation to create a new OAuth client. OAuth 2.0 Authorization Flow#
Step 1: Request User Authorization#
When a user clicks the "Sign in with Google" button, your website sends a request to Google's OAuth 2.0 authorization server to obtain permission to access the user's Google account.The authorization request is sent to https://accounts.google.com/o/oauth2/v2/auth/ with the following parameters:| Parameter | Required | Description |
|---|
client_id | Required | The client ID for your application from the API Console Credentials page |
redirect_uri | Required | Where the API server redirects the user after authorization. Must exactly match one of the authorized redirect URIs in your OAuth 2.0 client configuration |
response_type | Required | Set to code for web server applications to receive an authorization code |
scope | Required | Space-delimited list of scopes identifying the resources your application can access on the user's behalf |
access_type | Recommended | online (default) or offline. Use offline if your application needs to refresh access tokens when the user is not present |
state | Recommended | Any string value to maintain state between your authorization request and the authorization server's response |
This table shows the basic parameters required by Google OAuth 2.0. Many other optional parameters are available to customize the user experience and security. See the official documentation for complete details. Step 2: User Grants Authorization#
Google presents a consent screen requesting permission to access the specified resources.User approves: Google sends an authorization token to your web server
User denies: Google sends an error message to your web server
Step 3: Exchange Authorization Code for Access Token#
After the user grants permission, the authorization code is included in the response. The response appears in the query string:# Error response
http://example.com/#error=access_denied&state=state_parameter_passthrough_value
# Success response
http://example.com/#state=state_parameter_passthrough_value&access_token=***&token_type=Bearer&expires_in=***&scope=email%20https://www.googleapis.com/auth/userinfo.email%20openid&authuser=0&prompt=consent
Step 4: Access Protected Resources#
Using the Openidconnect API as an example, you can access the user's Google account information by sending a request with the access token.1.
Create a new request in your Apidog project
2.
Use the URL: https://openidconnect.googleapis.com/v1/userinfo?access_token=ACCESS_TOKEN
3.
Replace ACCESS_TOKEN with your actual token
Valid token: Google responds with the user's information
Invalid/expired token: Google responds with an error message
picture and email. Your website can use this data to automatically display the user's profile without manual entry.Benefits of Using Apidog for OAuth 2.0 Testing#
Using Apidog to debug OAuth 2.0 APIs provides:Clear visibility into parameters required by upstream and downstream processes
Optimized development experience with visual parameter management
Workflow validation before writing code
Reduced debugging time during implementation
References#
π Example Web Page Source Code
Modified atΒ 2026-01-23 07:17:04
