API Integration for Web & Desktop

I need an experienced developer to wire a third-party API into both my web and desktop applications so that data flows smoothly and stays in sync everywhere it is presented—on pages, animated banners, and even Canva-exported assets embedded in the site.

The goal is data synchronization. Two flavours are required:
• Real-time updates for anything the user triggers or that changes frequently.
• Scheduled batch updates to catch everything else on a predictable cadence.

The web layer is built with standard HTML / CSS and lightweight animations; the desktop side is a standalone app that already exposes internal endpoints. Your job is to connect the external API to these two fronts, handle mapping, conflict resolution, error logging, and confirm that changes made in one environment appear in the other according to the timing rules above.

Deliverables
• Fully working API integration for both platforms
• Source code with clear in-line comments
• Setup scripts or build instructions
• Postman (or similar) collection covering key calls
• One-page technical walkthrough so I can extend or hand over maintenance later

Acceptance criteria
1. Creating, updating, or deleting a record in either application is reflected in the other within seconds (real-time path) or during the next scheduled run.
2. No data loss or duplication is observed in stress tests of 10,000+ records.
3. Error handling, retry logic, and concise logging are in place and demonstrated.

REST, JSON, webhooks, cron jobs, or the libraries you prefer are all fine as long as they are robust and well-documented. Let me know if you need access keys or sample payloads; I can supply those right away.