I will fix oauth, API authentication, access token and authorization errors

J
joel_adams1
J
joel_adams1
Joel A
fix oauth, API authentication, access token and authorization errors
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fix oauth, API authentication, access token and authorization errors

About this gig

Is your API returning 401 Unauthorized, 403 Forbidden, invalid token, expired token or OAuth errors?


I can troubleshoot and fix authentication and authorization problems affecting your API integration.


I work with OAuth 2.0, API keys, access tokens, refresh tokens, bearer authentication, JWT and third-party API authentication systems.


I can help with:

  • OAuth 2.0 setup and troubleshooting
  • OAuth callback errors
  • Access token problems
  • Refresh token issues
  • Expired token handling
  • 401 Unauthorized errors
  • 403 Forbidden errors
  • API key configuration
  • Bearer token authentication
  • JWT authentication
  • Authorization scopes
  • Redirect URI problems
  • Client ID and client secret configuration
  • Token refresh automation
  • Third party API authentication


I can troubleshoot integrations involving Shopify, Google APIs, Stripe, Microsoft, HubSpot, WooCommerce, custom APIs and other OAuth enabled platforms.


My goal is to identify the authentication failure, correct the implementation and verify that the API requests work reliably.


Send me the error message or API documentation before ordering so I can assess the issue and recommend the appropriate package.

  • Expertise

    • Algorithms & Data structures
    • Debugging
    • Localization
    • Performance
    • Security

  • Programming language

    • JavaScript

  • Frontend framework

    • Angular
    • Ember.js
    • Next.js
    • Nuxt.js
    • Tailwind CSS

  • Backend framework

    • Django
    • Laravel
    • CakePHP
    • Express.js
    • FastAPI

Get to know Joel A

Joel A

Full stack developer building AI powered SaaS and scalable web applications

  • FromUnited Kingdom
  • Member sinceApr 2026
  • Avg. response time1 hour

  • Languages

    English
Hi, I’m a results driven full stack developer specializing in API integration, AI powered SaaS MVPs, and scalable web applications. I help startups and businesses turn ideas into high performing products using React, Next.js, Supabase, Firebase, and automation tools like Zapier, n8n, and Make. From OAuth2, JWT authentication, and Stripe payments to custom REST APIs and AI agents, I deliver secure, fast, and reliable solutions. Clean code, clear communication, and on time delivery are my standards. Let’s build something powerful together.