---
title: "Re-check a stored immutable chain link"
method: GET
path: "/api/v1/chain/verify"
tags: ["Integrity"]
---

# Re-check a stored immutable chain link

`GET /api/v1/chain/verify`

## Request

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

Public endpoint. Recomputes one stored link's content hash, resolves its exact signing-key id, checks the Ed25519 signature, and checks prev_hash against the preceding stored link. With no link_index it checks the current head. Storage failures return 503 rather than being misreported as cryptographic failures.

## Query parameters

- `link_index` integer

## Response `200`

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

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

## Other responses

- `400`: Malformed link_index.
- `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)