Aster API Authentication
Base: https://fapi.asterdex.com. Signed: send timestamp (ms), signature; optional recvWindow (default 5000, ≤5000).
| Param | Description |
|---|---|
| user | Main account wallet |
| signer | API wallet |
| nonce | Current time, microseconds |
| signature | EIP-712 (hex) |
Nonce: Current system time in µs; invalid if ±~5s. Prefer monotonic (e.g. now_s×1e6 + sequence). Example: see reference.
Signing: (1) Param string: key=value, sort ASCII, all strings; include nonce, user, signer. (2) EIP-712: domain name "AsterSignTransaction", version "1", chainId 1666, verifyingContract "0x0000...0000"; type "Message", field "msg" = param string. (3) Encode typed data, sign with API wallet private key (ECDSA), hex. (4) Add signature to query or body; POST/DELETE: application/x-www-form-urlencoded. Security: Env vars for user, signer, key. GET /fapi/v3/time if clock skew.
Note on chainId 1666 (SEC-08): The chainId 1666 used in the EIP-712 signing domain is an off-chain signing identifier specific to AsterDex. It is NOT the Harmony ONE network chainId, even though Harmony uses the same number. This chainId is used exclusively for API request signing and has no relation to the on-chain deposit chainId (ETH=1, BSC=56, Arbitrum=42161). Do not confuse the two.
Payload shapes: reference.md.