v3
latestOpenAPI 3.1.02026-07-3173143.7 KBFlash
Cancel an order
Cancel a previously submitted flash order.
Signature required. Construct the canonical UTF-8 cancel message and sign it with the funder wallet:
- Message format: "Definitive Flash v1 — Cancel Order\nOrder: <orderId>" — identical bytes across EVM and SVM; only the signing primitive differs.
- EVM chains — sign with EIP-191 personal_sign over the message bytes; pass the 65-byte 0x-prefixed hex signature as userSignature.
- SVM (solana) — sign with Ed25519 over the message bytes; pass the 64-byte base58 signature as userSignature.
- Echo the exact message text back as cancelMessage.
Idempotent: cancelling an already-cancelled order returns 200, not 422.
post/orders/{orderId}/cancel
Path parameters
orderIdstring uuid required
Flash order ID.
Request body
Response
Order cancelled (or already cancelled)