I have a SaaS platform for managing ad campaigns. Some code for integrating Meta Ads (Facebook/Instagram) and Google Ads APIs has been started, but it’s not fully functional. I need an experienced developer to complete and properly implement the integrations so that the platform can: Requirements / Deliverables: Meta Ads Integration Connect to the Meta Marketing API. Support campaign creation, editing, and retrieval of performance metrics (impressions, clicks, cost, etc.). Handle ad account authorization and token management securely. Google Ads Integration Connect to Google Ads API. Support campaign creation, editing, and retrieval of metrics. Handle OAuth authentication and token refresh correctly. Error Handling & Logging Properly handle API errors and rate limits. Log actions for auditing and debugging. Frontend Integration Ensure the existing SaaS UI can trigger ad actions and display campaign data. Implement a clean, user-friendly experience for managing campaigns. Testing & Documentation Provide test scripts or instructions to verify functionality. Update or add documentation for future developers. Skills Required Strong experience with Meta Marketing API and Google Ads API. Experience with Node.js / Express / React (or relevant tech stack). OAuth 2.0 / API token handling. SaaS or campaign management system experience is a plus. Project Details Current platform stack: React (frontend) + Node.js + Express (backend) The project is partially completed; developer will continue and finalize the integration. Access to existing code repository (GitHub) will be provided. How to Apply Share previous experience with ad platform API integrations. Estimate the time required to complete the project. Provide GitHub or code samples if possible.