---
title: "Store a fiat mint custodian EIP-712 signature"
method: POST
path: "/signing/fiat-mint"
tags: ["signing"]
---

# Store a fiat mint custodian EIP-712 signature

`POST /signing/fiat-mint`

## Request body

- SubmitSignatureDto
  - `mintRef` string, required — bytes32 hex mint reference (0x-prefixed, 64 hex chars)
  - `receiver` string, required — Ethereum receiver address
  - `usdAmount` string, required — USD amount as integer string (scaled by 10^2)
  - `validUntil` number, required — Unix timestamp — valid until
  - `chainId` 1 | 137 | 143 | 8453 | 42161 | 10143 | 84532 | 11155111, required — Blockchain chain ID
  - `signature` string, required — 65-byte hex signature (0x-prefixed, 130 hex chars)

## Response `201`

Signature stored successfully

- SubmitSignatureResponseDto
  - `success` boolean, required — Whether the operation succeeded
  - `message` string — Human-readable result message
  - `id` string — Created record ID

## Other responses

- `400` — Invalid signature or expired
- `401` — Unauthorized
- `403` — Forbidden — Admin role required or not a custodian
- `409` — Duplicate mintRef

---

[API](https://skmtc.dev/dre/apis/dre-api.md) · [All operations](https://skmtc.dev/dre/apis/dre-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/dre/dre-api/revisions/5d14beb9482b/schema)