> ## Documentation Index > Fetch the complete documentation index at: https://flash.definitive.fi/docs/llms.txt > Use this file to discover all available pages before exploring further. # Cancel orders in batch > Cancel up to 25 flash orders with one funder signature. Returns 200 with one result per order id, in request order; partial success is reported per order, never as a whole-call failure. **Signature required.** Construct the canonical UTF-8 batch cancel message and sign it with the funder wallet: - Message format: `"Definitive Flash v1 — Cancel Orders\nOrders:\n\n..."` — one lowercase UUID per line, in the same order as `orderIds`, no trailing newline. 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`. One wallet per batch: ids the signer does not fund come back `NOT_FOUND` and the rest proceed. A `userSignature` that is not valid hex or base58 is rejected with `400 INVALID_SIGNATURE` before any lookup; a well-formed signature that fails to verify is reported per order as `NOT_FOUND`, never as a 4xx. Each result mirrors single cancel: `ok: true` for a fresh or already-cancelled order; otherwise `ok: false` with an `errorCode` standing in for the status single cancel would have returned. `PENDING_CANCEL` means a cancel is already in flight — treat it as cancelled and confirm via `GET /orders/{orderId}`. Cancelling an entry order never cancels its attached bracket pair; include the bracket's own id to cancel it. ## OpenAPI ````yaml https://flash.definitive.fi/v1/openapi.json post /orders/cancel openapi: 3.1.0 info: title: Definitive Flash API version: 2.0.0 description: Flash swap API for decentralized token trading. servers: - url: https://flash.definitive.fi/v1 security: [] paths: /orders/cancel: post: tags: - Flash summary: Cancel orders in batch description: >- Cancel up to 25 flash orders with one funder signature. Returns 200 with one result per order id, in request order; partial success is reported per order, never as a whole-call failure. **Signature required.** Construct the canonical UTF-8 batch cancel message and sign it with the funder wallet: - Message format: `"Definitive Flash v1 — Cancel Orders\nOrders:\n\n..."` — one lowercase UUID per line, in the same order as `orderIds`, no trailing newline. 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`. One wallet per batch: ids the signer does not fund come back `NOT_FOUND` and the rest proceed. A `userSignature` that is not valid hex or base58 is rejected with `400 INVALID_SIGNATURE` before any lookup; a well-formed signature that fails to verify is reported per order as `NOT_FOUND`, never as a 4xx. Each result mirrors single cancel: `ok: true` for a fresh or already-cancelled order; otherwise `ok: false` with an `errorCode` standing in for the status single cancel would have returned. `PENDING_CANCEL` means a cancel is already in flight — treat it as cancelled and confirm via `GET /orders/{orderId}`. Cancelling an entry order never cancels its attached bracket pair; include the bracket's own id to cancel it. requestBody: content: application/json: schema: $ref: '#/components/schemas/BatchCancelOrderRequest' responses: '200': description: Per-order results, in request order content: application/json: schema: $ref: '#/components/schemas/BatchCancelOrderResponse' '400': description: Invalid request parameters content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Authentication failed content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: Permission denied content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: Resource not found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '422': description: Resource state prevents the requested operation content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '429': description: Rate limit exceeded content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '503': description: Service temporarily unavailable content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '504': description: Gateway timeout content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - ApiKeyAuth: [] components: schemas: BatchCancelOrderRequest: type: object properties: orderIds: type: array items: type: string pattern: ^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$ minItems: 1 maxItems: 25 description: >- 1–25 order ids to cancel, as lowercase hyphenated UUIDs, in the same order as the lines of `cancelMessage`. Duplicates are rejected. cancelMessage: type: string minLength: 1 description: >- UTF-8 plaintext the funder wallet signed. Format: "Definitive Flash v1 — Cancel Orders\nOrders:\n\n..." — one lowercase UUID per line in `orderIds` order, no trailing newline. Same bytes across EVM and SVM. userSignature: type: string minLength: 1 description: >- 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. required: - orderIds - cancelMessage - userSignature BatchCancelOrderResponse: type: object properties: results: type: array items: $ref: '#/components/schemas/BatchCancelOrderResult' description: One result per requested order id, in request order. required: - results ErrorResponse: type: object properties: error: type: object properties: code: type: string message: type: string details: nullable: true required: - code - message required: - error BatchCancelOrderResult: type: object properties: orderId: type: string description: The requested order id. ok: type: boolean description: >- True when the order was cancelled or was already cancelled; false otherwise. errorCode: $ref: '#/components/schemas/BatchCancelErrorCode' required: - orderId - ok BatchCancelErrorCode: type: string minLength: 1 description: >- Present only when `ok` is false. Why that order was not cancelled: - `NOT_FOUND` — no such order, not a root Flash order, or the signer is not its funder. Drop it. - `ALREADY_FILLED` — the order filled before the cancel landed. Drop it. - `REJECTED` — the order was already rejected. Drop it. - `PENDING_CANCEL` — a cancel is already in flight for this order. Treat as cancelled and confirm via `GET /orders/{orderId}`. - `SETTLING` — the order's status is not known yet; re-check shortly. - `INTERNAL_ERROR` — transient failure; retry this id. Treat any other value as terminal for that order and do not retry it. example: ALREADY_FILLED securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-definitive-api-key description: Your Definitive API key. x-default: dpka_513a2bd7_57a2_46d2_927b_2a3857fe271b ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.