eBay API Listing Automation

I need a clean, well-documented integration that lets my in-house system talk to the eBay Inventory/Trading APIs so I can manage physical product listings without touching the web interface. The integration must cover two core actions only:

• Add new listings (SKU, images, price, quantity, item specifics, shipping profile, etc.)
• Update existing listings (price, quantity, description and any revised specifics)

No delete or end-item logic is required at this stage.

Once finished I expect:
– OAuth application keys properly created and stored.
– A lightweight script or micro-service (PHP, Node.js or Python—choose what you’re strongest with) that wraps the required endpoints.
– Clear README explaining setup, environment variables and sample calls.
– A quick screen-share or concise video showing a live call that creates a new listing, then a second call that edits it.

Success is a repeatable workflow where my team can run a single command or hit a REST endpoint and see the listing appear or update on eBay within seconds, with all eBay responses logged for troubleshooting.