Signed actions

Every state change — orders, cancels, withdrawals, transfers, triggers, session management — is an Action: a protobuf message, signed, submitted to a single endpoint. If you use the TypeScript SDK this is handled for you; this page is what you need to implement it elsewhere.

The schema is served by the exchange

curl -sO https://api-mainnet.n1.xyz/schema.proto

Generate bindings from that file rather than from a vendored copy, so your client matches the deployment's version. Check the version you are talking to with GET /info and the Changelog. For the v22 take-all receipt changes, see the v22 changelog entry.

Submitting

POST /action
Content-Type: application/octet-stream

The body is the length-delimited protobuf encoding of the Action, immediately followed by the signature over those encoded bytes:

body = size_delimited(Action) || signature

The response is a length-delimited Receipt. A receipt whose kind is err carries an Error enum value — an HTTP 200 with an error receipt is a rejected action, not a success, so decode the receipt before treating a submission as executed.

The encoded action must be 1648 bytes or less, followed by a 64-byte signature. Batch with care: an atomic action containing many subactions can exceed the limit.

Required fields

Every Action carries:

Field	Value
currentTimestamp	Server time from GET /timestamp, not local clock time
nonce	Monotonic per signer; replayed or stale nonces are rejected
kind	The specific action (place order, cancel, withdraw, …)

Recover state after a restart with GET /event/last-acked-nonce for your signer and GET /action/last-executed-id. Using the client clock instead of /timestamp is the most common cause of otherwise-valid actions being rejected.

Signing

Actions are signed either by the wallet key or by a session key authorized by that wallet. Sessions exist so a trading process never holds the wallet key — see Accounts and sessions. Session-signed actions carry the sessionId inside the action kind.

Session creation supports two signature framings, hex and solanaTransaction, the latter for wallets that will only sign a Solana transaction rather than an arbitrary message.

Units

All prices, sizes, and amounts in actions are scaled integers, using the market's priceDecimals / sizeDecimals or the token's decimals from GET /info. Quote notional amounts scale by priceDecimals + sizeDecimals. u128 values are carried as hi / lo pairs. Sending a human-readable decimal where an integer is expected is silently a very different order.

Checklist

1. Fetch /info once; cache market and token IDs and decimals.
2. Fetch /timestamp before signing.
3. Track your nonce.
4. Encode length-delimited, sign, append the signature.
5. POST /action as application/octet-stream.
6. Decode the Receipt, and check for err.