EUR ≠ USD. CSFloat and Waxpeer quote USD; Skinport and SkinBaron quote EUR. Convert explicitly — do not compare raw numbers.
Retail Western premium. Skinport often sits above YouPin wholesale after FX. That is normal (convenience, EU payment methods, buyer trust) — not automatically an arb to short Skinport.
Listing ≠ completed sale. Validate thin knives with market sales search:
curl -s "https://api.cspriceapi.com/v1/market-sales/search?market_hash_name=M4A1-S%20%7C%20Printstream%20(Field-Tested)" \
-H "Authorization: Bearer YOUR_API_KEY"
Skinport official API vs CSPriceAPI. Skinport offers a partner API for sellers. CSPriceAPI aggregates Skinport alongside 12 other markets with one auth header — better for comparison sites and multi-market bots.