> ## Documentation Index > Fetch the complete documentation index at: https://docs.brdg.now/llms.txt > Use this file to discover all available pages before exploring further. # Submit fast fill signature > Checks that the signature recovers to `owner` over exactly the built message, then hands it to the venue's relayer, which sends the source transaction and pays its gas. `txHash` is that transaction once the venue names it, usually within seconds. `txHash: null` with `status: "PENDING"` means the relayer holds the signature and has not broadcast yet; BRDG keeps tracking it, and submitting again is safe. Send the one time Permit2 `approve` through `POST /bridge/transfers/{id}/submit` with `step: "approve"` first. ## OpenAPI ````yaml openapi/openapi.json POST /fastfill/transfers/{id}/submit openapi: 3.1.0 info: title: BRDG API version: 1.0.0 description: >- Quote, build, submit and track cross-chain transfers across every venue BRDG aggregates. servers: - url: https://api.brdg.now/v1 security: [] paths: /fastfill/transfers/{id}/submit: post: tags: - fastfill summary: Submit fast fill signature description: >- Checks that the signature recovers to `owner` over exactly the built message, then hands it to the venue's relayer, which sends the source transaction and pays its gas. `txHash` is that transaction once the venue names it, usually within seconds. `txHash: null` with `status: "PENDING"` means the relayer holds the signature and has not broadcast yet; BRDG keeps tracking it, and submitting again is safe. Send the one time Permit2 `approve` through `POST /bridge/transfers/{id}/submit` with `step: "approve"` first. parameters: - schema: type: string pattern: >- ^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$ required: true name: id in: path - name: X-BRDG-Api-Key in: header required: false description: >- Optional partner key for server integrators. With it, each wallet is rate limited under the partner rather than on the IP of the calling server (a call naming no wallet, per the `userIp` in the body), bounded by a partner-wide ceiling. Unknown or disabled keys are refused with 401. See [rate limits](/api-reference/rate-limits). schema: type: string requestBody: required: true content: application/json: schema: type: object properties: signature: type: string pattern: ^0x[0-9a-fA-F]{130,20000}$ description: >- The wallet's 65 byte EIP-712 signature over the build's message, as 0x hex. userIp: anyOf: - type: string format: ip - type: string format: ip description: The end user's IP address, if the quote carried one. required: - signature example: signature: >- 0xedc90fdd27654dd49ac1087901450c9c5fdf444943f61faa8d787bee86304d821f06a5db4a67eddf5cf286014d6ec8bd33c64f9e072045a9f3c5e50cc28960fc1b responses: '200': description: The transfer’s new state and the relayer’s hash, when known content: application/json: schema: type: object properties: transferId: type: string status: type: string txHash: type: string nullable: true step: type: string enum: - approve - fee - main - redeem accepted: type: boolean verification: type: string nullable: true enum: - verified - pending - unverified_no_rpc - unverified_rpc_error - refuted - null required: - transferId - status - txHash - step - accepted - verification example: transferId: 6f1d2c0a-4b7e-4c55-9a1e-2f0e8c3b7d41 status: SUBMITTED txHash: >- 0x8f3c2b1a9d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c0d9e8f7a6b5c4d3e2f1a step: main accepted: true verification: pending '400': description: >- Malformed request, an unknown asset, or a signed transaction that is not what we built content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string details: type: object additionalProperties: nullable: true retryAfterMs: type: integer required: - code - message required: - error '401': description: >- An `X-BRDG-Api-Key` header was sent and the key is unknown (`invalid_api_key`) or disabled (`api_key_disabled`) content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string details: type: object additionalProperties: nullable: true retryAfterMs: type: integer required: - code - message required: - error '404': description: No such decision or transfer, or the aggregator is switched off content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string details: type: object additionalProperties: nullable: true retryAfterMs: type: integer required: - code - message required: - error '409': description: >- The decision is indicative, the quote expired or drifted, the venue is ineligible, or execution is switched off content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string details: type: object additionalProperties: nullable: true retryAfterMs: type: integer required: - code - message required: - error '429': description: Rate limited; retry after `retryAfterMs` content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string details: type: object additionalProperties: nullable: true retryAfterMs: type: integer required: - code - message required: - error '502': description: The venue refused to build, or the broadcast was rejected content: application/json: schema: type: object properties: error: type: object properties: code: type: string message: type: string details: type: object additionalProperties: nullable: true retryAfterMs: type: integer required: - code - message required: - error ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.