> ## 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.

# Verify Blockchain Anchors

> Verify that Merkle roots match your events and the anchor chain is intact.

## Overview

Anchor verification confirms two things:

1. **Anchor integrity** (`valid`) — the Merkle root stored in the anchor matches the Merkle root recomputed from the underlying events.
2. **Anchor chain integrity** (`chain_valid`) — the `previous_anchor_hash` correctly references the preceding anchor.

If either check fails, your audit trail may have been tampered with between event ingestion and blockchain submission.

## List Anchors

Retrieve your workspace's blockchain anchors:

<CodeGroup>
  ```bash cURL theme={null}
  curl https://getimmutable.dev/api/v1/anchors?limit=10 \
    -H "Authorization: Bearer imk_your_api_key_here"
  ```

  ```typescript JavaScript theme={null}
  import { ImmutableClient } from "getimmutable";

  const client = new ImmutableClient({
    apiKey: "imk_your_api_key_here",
    baseUrl: "https://getimmutable.dev",
  });

  const anchors = await client.getAnchors(10);
  ```

  ```python Python theme={null}
  from getimmutable import ImmutableClient

  client = ImmutableClient(
      api_key="imk_your_api_key_here",
      base_url="https://getimmutable.dev",
  )

  anchors = client.get_anchors(limit=10)
  ```

  ```php Laravel theme={null}
  use GetImmutable\AuditLog;

  $anchors = AuditLog::client()->getAnchors();
  ```
</CodeGroup>

## Get Anchor Detail

Retrieve a single anchor with additional fields (`first_event_hash`, `last_event_hash`):

<CodeGroup>
  ```bash cURL theme={null}
  curl https://getimmutable.dev/api/v1/anchors/anc_abc123 \
    -H "Authorization: Bearer imk_your_api_key_here"
  ```

  ```typescript JavaScript theme={null}
  const anchor = await client.getAnchor("anc_abc123");
  console.log(anchor.data.explorer_url);
  // https://basescan.org/tx/0x7a8b...
  ```

  ```python Python theme={null}
  anchor = client.get_anchor("anc_abc123")
  print(anchor["data"]["explorer_url"])
  ```

  ```php Laravel theme={null}
  $anchor = AuditLog::client()->getAnchor('anc_abc123');
  ```
</CodeGroup>

## Verify an Anchor

The verify endpoint recomputes the Merkle root from the underlying events and checks the anchor chain:

<CodeGroup>
  ```bash cURL theme={null}
  curl https://getimmutable.dev/api/v1/anchors/anc_abc123/verify \
    -H "Authorization: Bearer imk_your_api_key_here"
  ```

  ```typescript JavaScript theme={null}
  const result = await client.verifyAnchor("anc_abc123");

  if (result.data.valid && result.data.chain_valid) {
    console.log("Anchor verified. Merkle root and chain are intact.");
  } else {
    console.error("Anchor verification failed!", result.data);
  }
  ```

  ```python Python theme={null}
  result = client.verify_anchor("anc_abc123")

  if result["data"]["valid"] and result["data"]["chain_valid"]:
      print("Anchor verified.")
  else:
      print("Verification failed!", result["data"])
  ```

  ```php Laravel theme={null}
  $result = AuditLog::client()->verifyAnchor('anc_abc123');

  if ($result['data']['valid'] && $result['data']['chain_valid']) {
      Log::info('Anchor verified');
  } else {
      Log::critical('Anchor verification failed', $result['data']);
  }
  ```
</CodeGroup>

## 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"
  }
}
```

## Response Fields

| Field          | Type    | Description                                                                  |
| -------------- | ------- | ---------------------------------------------------------------------------- |
| `anchor_id`    | string  | The anchor identifier                                                        |
| `merkle_root`  | string  | The 64-character hex Merkle root stored in this anchor                       |
| `valid`        | boolean | Whether the recomputed Merkle root matches the stored one                    |
| `chain_valid`  | boolean | Whether the `previous_anchor_hash` correctly references the preceding anchor |
| `expected`     | string  | The Merkle root recomputed from the underlying events                        |
| `actual`       | string  | The Merkle root stored in the anchor record                                  |
| `events_count` | integer | Number of events included in this anchor's Merkle tree                       |
| `tx_hash`      | string  | The blockchain transaction hash (null if not yet confirmed)                  |
| `explorer_url` | string  | Direct link to the transaction on Basescan                                   |

## Understanding Failures

### `valid: false`

The Merkle root recomputed from the underlying events does not match the stored Merkle root. This means events were modified, inserted, or deleted after the anchor was created. The `expected` and `actual` fields show the mismatch.

### `chain_valid: false`

The `previous_anchor_hash` does not match the expected value computed from the preceding anchor's `merkle_root` and `tx_hash`. This means an anchor was modified, inserted into, or deleted from the anchor chain.

## Verify All Anchors

To verify every anchor in your workspace:

```typescript theme={null}
const anchors = await client.getAnchors(100);

for (const anchor of anchors.data) {
  const result = await client.verifyAnchor(anchor.id);

  if (!result.data.valid || !result.data.chain_valid) {
    console.error(`Anchor ${anchor.id} failed verification`, {
      valid: result.data.valid,
      chain_valid: result.data.chain_valid,
      period: `${anchor.period_start} — ${anchor.period_end}`,
    });
  }
}
```

<Tip>
  After verifying via the API, cross-check confirmed anchors on Basescan for fully independent verification. See [Verify On-Chain](/trust/verify-on-chain).
</Tip>