Auth: Cancel

Alpha Version

The Ostium Builder Service is in Alpha. API endpoints, specifications, and builder URLs may change without notice. Use with caution in production environments.

POST /v1/auth/cancel

Returns a message that the trader must sign to cancel an unverified delegate wallet.

Headers

Header	Required	Description
`X-Trader-Address`	Yes	Trader wallet address.
`Content-Type`	No	`application/json` or `text/plain` (JSON string).

Response Body

Field	Type	Required	Description
`message`	`string`	Yes	Message to sign (EIP-191 / `personal_sign`).
`nonce`	`string`	Yes	Nonce embedded in the message.
`expiresAt`	`string`	Yes	ISO expiry time.
`smartAccountAddress`	`string`	Yes	Smart account address.

Example

curl -X POST https://builder.ostiscan.xyz/v1/auth/cancel \
  -H "X-Trader-Address: 0xYourWallet"

Example Response

{
  "message": "<signable message returned by server>",
  "nonce": "0x...",
  "expiresAt": "2026-02-05T12:34:56.789Z",
  "smartAccountAddress": "0x..."
}

Notes

Use this only for unverified delegate wallets.
If the message expires, call this endpoint again for a fresh message.

Errors

See /docs/errors.