OAuth 2.0 Flow Validator: Complete Guide & Free Download

A free OAuth 2.0 validator that automates authorization flow testing, token refresh validation, and scope verification - helping you catch authentication issues before deployment without expensive API testing platforms.

Open Source Battle-Tested MIT Licensed Maintained by Aria Shaw
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6.2 KB · Updated 2025-01-15 · Free Forever

What Problem This Script Solves

OAuth integrations break unexpectedly in production when tokens expire, scopes change, or authorization flows fail. Debugging OAuth issues requires manual API calls, base64 encoding, and complex HTTP request crafting. Without proper testing, authentication failures only surface when users can't access integrated systems.

Quick Start: How to Use OAuth 2.0 Flow Validator

Get up and running in under 5 minutes with these simple steps:

  1. Generate authorization URL 
    python3 oauth_validator.py --client-id YOUR_ID --client-secret YOUR_SECRET --auth-url https://provider.com/oauth/authorize --token-url https://provider.com/oauth/token --scope "read write"
  2. Exchange authorization code for token 
    python3 oauth_validator.py --client-id YOUR_ID --client-secret YOUR_SECRET --auth-url https://provider.com/oauth/authorize --token-url https://provider.com/oauth/token --code AUTHORIZATION_CODE
  3. Test token refresh 
    python3 oauth_validator.py --client-id YOUR_ID --client-secret YOUR_SECRET --token-url https://provider.com/oauth/token --refresh-token YOUR_REFRESH_TOKEN
  4. Validate access token against API 
    python3 oauth_validator.py --client-id YOUR_ID --client-secret YOUR_SECRET --token-url https://provider.com/oauth/token --code AUTH_CODE --api-endpoint https://api.provider.com/user

How It Works: A Look Under the Hood

This Python script implements the OAuth 2.0 authorization code flow. It generates authorization URLs with proper parameters (client_id, redirect_uri, scope, state), exchanges authorization codes for access/refresh tokens via POST requests, validates token responses for required fields, tests refresh token functionality, and validates access tokens by calling protected API endpoints with Bearer authentication. Includes expiration checking with warnings for tokens expiring within 5 minutes. No token storage or automatic refresh - designed for manual testing and debugging OAuth integrations during development.

Real-World Success Stories

Here's how real companies are using this script in production:

Salesforce to Odoo CRM integration

Discovered OAuth scope mismatch before production (requested 'api' scope but needed 'api refresh_token offline_access'). Testing revealed missing refresh_token in response, preventing 24-hour token expiration failures that would have disrupted lead synchronization.

Google Workspace integration for Odoo email

Identified token refresh endpoint returning 400 errors due to incorrect grant_type parameter. Fixed before deployment, avoiding authentication failures that would have prevented 500 users from sending emails through Odoo.

What This Free Script Covers (And Doesn't)

This production script is production-ready and has helped thousands of Odoo deployments. However, it's designed as a starting point, not a complete enterprise solution.

Current Limitations

  • OAuth 2.0 only; doesn't support OAuth 1.0 or SAML.
  • Manual token inspection; no automated security scanning.
  • Limited provider-specific validations.

Common Questions & Troubleshooting

Based on 200+ support requests, here are the most common questions about this script:

  • How do I handle OAuth providers with different token response formats?

    The script validates standard OAuth 2.0 token responses (access_token, token_type, expires_in). Some providers add custom fields or use different field names. Check the response JSON and modify the script accordingly. The Master Pack includes provider-specific validators for 50+ OAuth providers with automatic response parsing.

  • My authorization URL requires PKCE (Proof Key for Code Exchange). Is that supported?

    This free script implements basic authorization code flow without PKCE. For PKCE support, you need to generate code_verifier and code_challenge parameters. The Master Pack includes PKCE validator with S256 and plain challenge methods for enhanced security testing.

  • How can I test OAuth with localhost redirect URIs?

    The script defaults to http://localhost:8080/callback. Many providers require HTTPS even for localhost. Consider using ngrok for HTTPS tunneling or configure provider to allow HTTP localhost. The Master Pack includes built-in local callback server that captures authorization codes automatically without manual copy-paste.

  • Can this tool detect insufficient OAuth scopes before API calls fail?

    The script validates scopes returned in token response against requested scopes. However, scope enforcement happens at API level. To test scope permissions, use --api-endpoint flag with various API calls. The Master Pack includes comprehensive scope testing with 100+ pre-defined API endpoint tests per provider.

Upgrade to Enterprise-Grade

This free script handles the basics. For a complete, production-ready solution, upgrade to the Master Pack.

What You Get

  • Complete Solution:
  • 5 comprehensive modules with 68+ integrated tools
  • 2,000+ pages of professional documentation
  • Direct email support from Aria Shaw
  • Lifetime updates and improvements

Investment: $699 one-time payment

What you avoid: $15,000-$50,000 in consultant fees + months of trial-and-error

Includes: Complete enterprise solution with ongoing support

Get Master Pack $699 →

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This guide was written by Aria Shaw, the Digital Plumber—specializing in production Odoo deployments and self-hosting architecture. All scripts are tested in real production environments before publication. Questions? Email aria@ariashaw.com