Fetching rates
Use the Get Rate endpoint to fetch current conversion rates.key field for each rate pair:
Rate keys
A rate key locks in a quoted conversion rate for a limited time. When you initiate an onramp or offramp request, pass therateKey from the rate response to guarantee the quoted price.
You can also create a custom rate key using the Create Ratekey endpoint if you need to apply a custom spread or margin. Verify a rate key is still valid using Verify Ratekey.
Rate keys expire. If a rate key expires before the transaction completes, the expireAction parameter on the ramp request controls what happens:
Fee bearer
When creating transactions, thefeeBearer parameter controls who pays the transaction fee:
Configure the default fee bearer in your merchant settings via the Update Settings endpoint.