> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getimmutable.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Public Verification

> Verify blockchain anchors without authentication — no API key, no trust required.

## Zero-Trust Verification

Immutable provides two public endpoints that require no authentication. Anyone — your customers, their auditors, regulators, or security researchers — can independently verify that your audit trail anchors are legitimate without trusting Immutable at all.

No API key. No account. No trust.

## Public Endpoints

### Look Up an Anchor by Transaction Hash

```
GET /api/v1/public/anchors/lookup?tx_hash=0x...
```

Given a blockchain transaction hash, returns the corresponding anchor record. This allows someone who found a transaction on Basescan to look up what it represents.

### Verify an Anchor

```
GET /api/v1/public/anchors/{id}/verify
```

Given an anchor ID, recomputes the Merkle root from the underlying events and checks that it matches the on-chain record.

<Note>
  These endpoints are rate-limited but do not require authentication. They are designed for independent, third-party verification.
</Note>

## Verification Walkthrough

A customer, auditor, or regulator can verify your audit trail's integrity without any access to your Immutable workspace:

<Steps>
  <Step title="Get the transaction hash">
    You provide them with a `tx_hash` from your anchor records (e.g., from a compliance report or dashboard export).
  </Step>

  <Step title="Look up the anchor">
    They call the public lookup endpoint to retrieve the anchor details:

    ```bash theme={null}
    curl "https://getimmutable.dev/api/v1/public/anchors/lookup?tx_hash=0x7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b"
    ```

    Response:

    ```json theme={null}
    {
      "data": {
        "id": "anc_abc123",
        "merkle_root": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
        "events_count": 1247,
        "period_start": "2026-03-27T00:00:00Z",
        "period_end": "2026-03-27T23:59:59Z",
        "chain": "base",
        "status": "confirmed",
        "tx_hash": "0x7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b",
        "block_number": 28451923,
        "explorer_url": "https://basescan.org/tx/0x7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b"
      }
    }
    ```
  </Step>

  <Step title="Verify the Merkle root">
    They call the public verify endpoint to confirm the Merkle root matches the underlying events:

    ```bash theme={null}
    curl "https://getimmutable.dev/api/v1/public/anchors/anc_abc123/verify"
    ```

    Response:

    ```json theme={null}
    {
      "data": {
        "anchor_id": "anc_abc123",
        "merkle_root": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
        "valid": true,
        "chain_valid": true,
        "expected": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
        "actual": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08",
        "events_count": 1247,
        "tx_hash": "0x7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b",
        "explorer_url": "https://basescan.org/tx/0x7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b3c4d5e6f7a8b"
      }
    }
    ```
  </Step>

  <Step title="Cross-check on Basescan">
    They open the `explorer_url` in a browser. On Basescan, they can:

    * Confirm the transaction exists and is confirmed
    * Read the `Anchored` event log in the transaction's logs tab
    * Extract the `merkleRoot` bytes32 value
    * Compare it to the `merkle_root` returned by the API

    If the values match, the audit trail for that period is verified.
  </Step>
</Steps>

## Error Responses

### Anchor not found

If the `tx_hash` does not correspond to any anchor:

```bash theme={null}
curl "https://getimmutable.dev/api/v1/public/anchors/lookup?tx_hash=0xinvalid"
```

```json theme={null}
{
  "error": "Not found",
  "message": "No anchor found for the given transaction hash."
}
```

Status: `404`

### Anchor not yet confirmed

If an anchor exists but has not yet been confirmed on-chain:

```json theme={null}
{
  "data": {
    "anchor_id": "anc_xyz789",
    "status": "submitted",
    "message": "This anchor has been submitted to the blockchain but is not yet confirmed."
  }
}
```

## Full Verification Chain

For maximum assurance, the verifier can combine all three approaches:

1. **Public API** — Confirm the Merkle root matches the events (`GET /api/v1/public/anchors/{id}/verify`)
2. **Basescan** — Confirm the Merkle root is recorded on-chain (`explorer_url`)
3. **Direct on-chain read** — Read the smart contract directly, bypassing both Immutable and Basescan ([Verify On-Chain](/trust/verify-on-chain))

<Tip>
  For compliance reports, include the `tx_hash` and `explorer_url` for each anchoring period. This gives auditors a direct path to independent verification without needing to contact Immutable.
</Tip>