---
title: "POST /fast-fill"
method: POST
path: "/fast-fill"
---

# POST /fast-fill

`POST /fast-fill`

## Headers

- `x-api-key` string, required

## Request body

- object
  - `requestId` string, required — The request ID of the request that needs to be fast filled
  - `solverInputCurrencyAmount` string — The input currency amount that the solver receives on origin
  - `maxFillAmountUsd` number — Optional per-request USD limit. If the computed fill value exceeds this amount, the request is rejected. Must be lower than or equal to the app's available USDC balance.

## Response `200`

Request was successful. It was either queued or found to be already executed.

- object — Request was successful. It was either queued or found to be already executed.
  - `message` string

## Other responses

- `400` — Bad Request - The request body contains invalid data.
- `401` — Unauthorized - Missing or invalid API key.
- `403` — Forbidden - No sponsoring wallet with app balance configured.
- `404` — The requested requestId could not be found.
- `409` — Conflict - This request is already being processed.
- `500` — Internal Server Error.

---

[API](https://skmtc.net/relay/apis/cross-chain-solver.md) · [All operations](https://skmtc.net/relay/apis/cross-chain-solver/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/relay/cross-chain-solver/revisions/428d669c2830/schema)