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This guide gets you to a working API call fast. You’ll need a sandbox API key — create one in seconds under Account → Manage Accounts in the sandbox dashboard (no approval needed). New here? See Initial Setup for full account setup, base URLs, and going to production.
1

Make your first call

Use the sandbox base URL https://api.sand.etherfuse.com and send your key in the Authorization header — with no Bearer prefix (see Authentication).A connectivity check is the simplest authenticated request:
curl https://api.sand.etherfuse.com/ramp \
  -H "Authorization: <your_sandbox_api_key>"
Or hit a public endpoint that needs no auth — list the available stablebonds:
curl https://api.sand.etherfuse.com/lookup/stablebonds
2

See what your customers can trade

Once authenticated, discover the assets available to ramp on a given chain. Use the identifier from the response when you create a quote.
curl "https://api.sand.etherfuse.com/ramp/assets?blockchain=solana" \
  -H "Authorization: <your_sandbox_api_key>"
See GET /ramp/assets.
3

Get a quote

Quotes return pricing (exchangeRate, feeBps, feeAmount, destinationAmount) and expire after 2 minutes. A quote needs an onboarded customerId, so complete onboarding first. The asset pair goes in quoteAssets (type is onramp, offramp, or swap).
curl -X POST https://api.sand.etherfuse.com/ramp/quote \
  -H "Authorization: <your_sandbox_api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "quoteId": "<uuid>",
    "customerId": "<onboarded_customer_uuid>",
    "blockchain": "solana",
    "sourceAmount": "1000",
    "quoteAssets": {
      "type": "onramp",
      "sourceAsset": "MXN",
      "targetAsset": "<token_identifier>"
    }
  }'
See POST /ramp/quote for the full payload, and the path-specific guides below for complete examples.

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Pick your path

Onramp

Fiat → tokens. The customer deposits MXN and receives tokens.

Offramp

Tokens → fiat. The customer sends tokens and receives MXN.

Swap

Token → token. The customer exchanges one asset for another.

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Next steps

Onboard customers

Most flows require a KYC’d customer with a linked bank account first.

Monitor with webhooks

Get real-time, HMAC-signed updates instead of polling.

Understand the model

Quote types, fees, order status flows, and resources.

Sandbox reference

Test KYC data, sandbox RFCs, and testnet token details.