Sandbox & Testing

Before going to production, test your integration in the Sandbox environment. All flows work identically to production, but no real funds are involved.

Accessing Sandbox

1. Contact your integration manager to receive Sandbox credentials.
2. Request whitelisting of your IP addresses for Sandbox usage.
3. Use the Sandbox endpoints below instead of production ones.

Sandbox URLs

Service	URL
Dashboard	https://sandbox-dashboard.mrcr.io
Widget (Redirect / Custom Tab)	https://sandbox-exchange.mrcr.io
Widget (for iFrame embedding)	https://sandbox-widget.mrcr.io
API Host	https://sandbox-api.mrcr.io

Testnet Addresses

Use these addresses when testing crypto transactions:

Network	Address	Supported Assets
BTC Testnet	msBE6aCaAesegu4VzbQW3L5xWBL8vi15Q7	Bitcoin
ETH Sepolia	0xbBC8f6B710359dbcdF02f9eb50Ade391890A6021	Ethereum (ETH), USDT

Test Payment Cards

Card 1 — Basic

• Number: 4444 4444 4444 3333
• Expiry: any future date
• CVV: 123
• Cardholder name: any name + surname

Card 2 — Success / Fail

• Number: 5555 4444 3333 1111
• Expiry: any future date
• CVV: 123 for success, 555 for failure
• Cardholder name: any name + surname

KYC in Sandbox

The Sandbox environment requires manually approving KYC reviews. If you don't want to wait for manual confirmation, use SumSub's test documents that have automatic processing: SumSub Verification Document Templates

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Production URLs

Once testing is complete, switch to production endpoints:

Service	URL
Dashboard	https://dashboard.mercuryo.io
Widget	https://exchange.mercuryo.io
Widget (iFrame embed)	https://widget.mercuryo.io
API Host	https://api.mercuryo.io

Migration Checklist

Before going live, make sure you've completed the following:

• Updated all URLs to production endpoints
• Obtained production credentials from the Dashboard
• Updated API keys to production keys
• Configured the callback URL in the production widget settings
• Tested the integration with a small amount in production before full launch