DEdefinitive
Flash

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

Request

  • Base URL
    https://flash.definitive.fi/v1
  • Auth
    API key in header x-definitive-api-key

Path parameters

orderIdstring uuid required

Flash order ID.

Request body

cancelMessagestring required

UTF-8 plaintext the funder wallet signed. Format: "Definitive Flash v1 — Cancel Order\nOrder: <orderId>". Same bytes across EVM and SVM.

userSignaturestring required

Funder wallet signature over cancelMessage. Accepts 0x-prefixed hex (EVM convention) or base58 (Solana convention). EVM: 65 bytes from EIP-191 personal_sign. SVM: 64 bytes from Ed25519.

Response

Order cancelled (or already cancelled)

oktrue required

Changes

No recorded changes to this operation across all 21 revisions of this API.