Content-to-Merchant API Migration

I need our existing product feed, which is currently pushed through the Google Content API, re-engineered so it runs on the Merchant API instead. The code that handles authentication, product insert/update, batch calls and error reporting all has to be ported or replaced, then tested end-to-end to confirm that every SKU arriving in Merchant Center matches what our back-office system holds.

The job breaks down into three practical steps:

1. Audit the present Content API implementation and document the calls, custom attributes and scheduling it relies on.
2. Build the equivalent flow for the Merchant API—handling OAuth 2.0, rate limits and pagination—then migrate the dataset without data loss.
3. Prove accuracy with a full sync, catch/resolve any disapproved items, and deliver concise hand-off notes so my team can maintain it.

Code is currently in Python, but I’m open to Node.js or another language if you can justify the gain. REST, JSON and standard Google API libraries are expected.

When you respond, tell me about similar migrations or Merchant Center integrations you’ve completed. A short outline of your approach and estimated timeframe is enough; I mainly want to see proven experience with these specific Google APIs.