---
title: "Re-check an API-shaped chain link"
method: POST
path: "/api/v1/chain/verify"
tags: ["Integrity"]
---

# Re-check an API-shaped chain link

`POST /api/v1/chain/verify`

## Request

- Base URL: `https://fonteum.com`
- URL: `https://fonteum.com/api/v1/chain/verify`
- Auth: none required

Public endpoint. Accepts a chain-link object and runs the same content-hash, exact-key Ed25519, and prev_hash checks as GET. UTC timestamps serialized with Z or +00:00 canonicalize to the same signed preimage.

## Request body

- object
  - `link_index` integer, required
  - `prev_hash` string, required
  - `attestation_id` integer, nullable, required
  - `attestation_content_hash` string, required
  - `content_hash` string, required
  - `signature` string, required
  - `public_key_id` string, required
  - `signed_at` string, date-time, required

## Response `200`

Cryptographic result. A failed check is valid=false with an errors array.

- object
  - `valid` boolean, required
  - `errors` string[], required

## Other responses

- `400`: Malformed JSON or link object.
- `503`: Chain or signing-key storage unavailable.

---

[API](https://skmtc.dev/fonteum/apis/fonteum-api.md) · [All operations](https://skmtc.dev/fonteum/apis/fonteum-api/llms.txt) · [OpenAPI document](https://skmtc.dev/fonteum/apis/fonteum-api/revisions/334e6e179d0d?raw)