A valid request URL is required to generate request examples{
"forwarder": "<string>",
"collector": "<string>",
"token": "<string>",
"estimatedXlmFee": "<string>",
"tokenAmount": "<string>",
"expiresAtLedger": 2
}{
"error": "simulation_failed",
"message": "could not simulate the provided calls"
}{
"error": "unauthorized"
}{
"error": "horizon_unreachable"
}Quote a gas-in-token fee
Request a fee quote for paying Soroban gas in a token instead of XLM. The facilitator simulates the calls, prices the XLM fee as a token amount, and returns the quote including the FeeForwarder contract address and a ledger-based expiry.
The SDK uses this quote to build the FeeForwarder.forward() authorization entry before calling POST /relay with feeToken set.
A valid request URL is required to generate request examples{
"forwarder": "<string>",
"collector": "<string>",
"token": "<string>",
"estimatedXlmFee": "<string>",
"tokenAmount": "<string>",
"expiresAtLedger": 2
}{
"error": "simulation_failed",
"message": "could not simulate the provided calls"
}{
"error": "unauthorized"
}{
"error": "horizon_unreachable"
}Authorizations
Server-held API key. Injected by the BFF (createRelayRoute / createSignerProxyRoute from @buckspay/nextjs). This key must only appear in server-side code and must never be shipped to a browser bundle.
Body
Request body for POST /fee/quote. Calls are simulated server-side to price the XLM fee as a token amount.
Stellar network identifier used in facilitator requests.
stellar-testnet, stellar-pubnet Payer address (G or C) whose account the fee will be deducted from.
^[GC][A-Z2-7]{55}$Token contract address (USDC SAC) used to pay the gas fee.
^C[A-Z2-7]{55}$Calls to simulate for fee estimation.
1Show child attributes
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Response
Fee quote computed successfully.
Fee quote returned by POST /fee/quote. Mirrors the SDK FeeQuote type from @buckspay/core.
FeeForwarder contract address. The SDK uses this to build the forward() authorization entry.
^C[A-Z2-7]{55}$Address that collects the fee (G or C). Embedded in the forward() invocation.
^[GC][A-Z2-7]{55}$Token used to pay the fee. Echoes the request token.
^C[A-Z2-7]{55}$Estimated XLM fee in stroops.
^\d+$Fee expressed in the requested token's smallest unit (USDC stroops for USDC). The SDK passes this as the fee_amount argument in the forward() invocation.
^\d+$Ledger sequence after which this quote expires. The SDK refuses to build a relay with an expired quote.
x >= 1