Overview
Use the Gas API to calculate relayer fees and obtain the cryptographic signatures required by the CashmereCCTP contracts. Quotes are deterministic for the current block state and expire 100 seconds after issuance.
GET /getEcdsaSig_native
Generates an ECDSA signature for EVM contracts (transfer, transferWithPermit, transferV2, transferV2WithPermit).
GET https://gas.cashmere.exchange/getEcdsaSig_native
Query Parameters
| Name | Type | Required | Description |
|---|
localDomain | number | ✅ | Origin Circle domain (Ethereum = 0, Arbitrum = 3, etc.). |
destinationDomain | number | ✅ | Target Circle domain. |
isV2 | boolean | ✅ | true for CCTP v2 flows (transferV2*), false for legacy v1. |
isNative | boolean | ✅ | true if relayer fee + gas drop will be paid in the origin’s native token. |
Example
curl "https://gas.cashmere.exchange/getEcdsaSig_native\
?localDomain=0\
&destinationDomain=3\
&isV2=true\
&isNative=false"
{
"fee": "1500000",
"deadline": "1729281534",
"signature": "0x8b6aa1…1f9d",
"isNative": false,
"cctpVersion": 2
}
Response Fields
| Field | Description |
|---|
fee | Relayer fee (USDC, 6 decimals when isNative=false, native units otherwise). |
deadline | UNIX timestamp that the contracts enforce (now + 100s). |
signature | ECDSA signature over (localDomain, destinationDomain, fee, deadline, isNative, cctpVersion). |
isNative | Echo of the query flag. |
cctpVersion | 1 or 2, matching the target function. |
Gas drops are not returned explicitly. When isNative=false, include your desired gasDropAmount in TransferParams and pass the same value to the contract.
GET /getEd25519Sig_native
Generates an Ed25519 signature for Solana, Aptos, or Sui transfers.
GET https://gas.cashmere.exchange/getEd25519Sig_native
Query Parameters
| Name | Type | Required | Description |
|---|
localDomain | number | ✅ | Origin domain. |
destinationDomain | number | ✅ | Target domain. |
isNative | boolean | ✅ | true for native fee flows. |
version | number | ❌ | Set to 2 when calling Solana transfer_v2. |
Example
curl "https://gas.cashmere.exchange/getEd25519Sig_native\
?localDomain=5\
&destinationDomain=0\
&isNative=false\
&version=2"
{
"signature": "0x6c80e3…d4",
"message": "0x0200000000000000000000000000000000000000000000000000000000000000e0fb080000000000",
"publicKey": "0x93ab6f…af",
"destinationDomain": "0",
"fee": "590000",
"deadline": "1729281534",
"isNative": false,
"version": 2
}
Message Layout
BCS-encoded fields (in order):
- Optional
version (u8).
- Optional
localDomain (u32) when isNative is provided.
destinationDomain (u32).fee (u64).deadline (u64).- Optional
isNative (bool).
Reproduce this byte order on-chain before verifying the signature.
Token Pricing
GET https://gas.cashmere.exchange/tokenPrices
{ domainId: priceInUsd } pulled from Redis.
WebSocket Updates
GET wss://gas.cashmere.exchange/subscribe
{ "type": "fees", "data": { <sourceChain>: { fee: { <dest>: { native, usd } }, gas: { native, usd } } } }{ "type": "tokenPrices", "data": { <domainId>: "<price>" } }
Use the socket to keep frontends in sync without repeatedly polling the REST endpoints.
Failure Modes
| HTTP Status | Description |
|---|
400 | Missing or invalid query parameters. |
500 | Redis cache is incomplete (MISSING_PRICE_DATA) or an internal error occurred. |
