eBay Canada API-based Trading Card Analyst

Backend Developer Needed — eBay Canada Market Insights API (Trading Cards)
(Prototype-level, clean architecture, no scraping)

We’re building a prototype-level but clean backend service that analyzes trading card demand and supply on eBay Canada.

This is not a hacky script and no scraping is allowed.
The goal is a well-structured, API-first prototype using official eBay APIs, with clear logic, explainable outputs, and a codebase we can safely evolve.

What You’ll Build (MVP Scope)

The service will:
Accept a JSON payload describing a trading card + cost (CAD)

Pull:
SOLD comps (7d / 30d / 90d)
ACTIVE listings (current supply)
Focus on eBay Canada (CAD-normalized)

Compute:
Sold counts & average/median sold prices
Active listing count & average listed price
Sold Confidence Score (0–100) with explanation
Supply Pressure Score
Estimated profit & margin based on cost
Return results via a clean REST API
Store results in a simple database (Postgres / SQLite acceptable)


Required
Strong backend skills (Node.js + TypeScript or Python + FastAPI)
Experience working with official eBay APIs
Comfortable designing analytics logic and simple scoring systems
Clean coding style (no one-off scripts)
Basic unit tests for core logic
Nice-to-have
Marketplace pricing / comps analysis experience
Experience handling ambiguous product data
Familiarity with rate limits, token refresh, retries

No scraping
No brittle regex-only solutions
No hardcoded assumptions without explanation