Sync CardMarket with CardBeast
Complete guide: from first setup to daily use
What CMSE is and why we use it
CMSE (Cardmarket Stock Exporter) is an open-source Chrome extension built by lupzn. It's the bridge between CardBeast and CardMarket: it takes the CSV you generate here and uploads it directly to your seller account.
We chose it because:
- Free and MIT-licensed — no cost, no lock-in
- Zero credentials stored (uses your browser session)
- Works without Powerseller status or API keys
- Actively maintained by the community
Initial setup
One-time, ~2 minutes
Install CMSE from the Chrome Web Store
Open the link above and click Add to Chrome. Also works on Edge and Brave.
Log in at cardmarket.com
Sign in with your seller account (Powerseller not required). The session stays active in your browser.
Check the CMSE icon in the top-right toolbar
If you don't see it, click the extensions pin and pin CMSE so it's always visible.
Back to CardBeast → Sync → CardMarket
From there you download CSVs and manage your inventory sync.
Daily workflow
Scan your cards
The AI identifies them and suggests a price based on eBay sold + CardMarket trend.
Click "Download CSV"
From Sync → CardMarket. The file is UTF-8 with semicolon separators, ready for CMSE.
Open cardmarket.com in your browser
Make sure you're logged in. If the session expired, sign in again before continuing.
CMSE icon → "Bulk Update" tab → upload the CSV
Important: pick "Bulk Update" (updates existing listings), not "Bulk List Cards" (creates new ones).
Confirm — done
CardMarket updates 47 listings in ~30 seconds. Keep the tab open until it finishes.
