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

# GET /hash

> Compute BLAKE3 cryptographic hash of the graph canonical export.

<ParamField path="method" type="GET">
  `/hash`
</ParamField>

**Authentication:** Required (if enabled)

Computes a BLAKE3 cryptographic hash of the graph's canonical binary export.
The hash is deterministic: the same graph state always produces the same 64-character hex digest.

<Info>
  Also returns the lightweight XOR-based checksum for fast comparisons. Use the BLAKE3 hash for
  cryptographic integrity verification; use the checksum for quick equality checks.
</Info>

## Response

<CodeGroup>
  ```json 200 OK — Success theme={null}
  {
    "success": true,
    "hash": "a3b4c5d6e7f8a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a1b2c3d4e5f6a7b8",
    "algorithm": "blake3",
    "checksum": 14823901234567890
  }
  ```

  ```json 500 Internal Server Error — Failure theme={null}
  {
    "success": false,
    "error": "Snapshot failed: ..."
  }
  ```
</CodeGroup>

| Field       | Type                  | Description                                 |
| ----------- | --------------------- | ------------------------------------------- |
| `success`   | boolean               | Whether the hash was computed successfully. |
| `hash`      | string or null        | 64-character BLAKE3 hex digest.             |
| `algorithm` | string or null        | Always `"blake3"`.                          |
| `checksum`  | integer (u64) or null | XOR-based deterministic checksum.           |
| `error`     | string or null        | Error message (if failed).                  |

## Example

```bash theme={null}
curl http://localhost:8080/hash \
     -H "Authorization: Bearer your-api-key"
```

```bash theme={null}
# Compare hash before and after a change
HASH_BEFORE=$(curl -s http://localhost:8080/hash | jq -r '.hash')
kremis ingest --file signals.json
HASH_AFTER=$(curl -s http://localhost:8080/hash | jq -r '.hash')
[ "$HASH_BEFORE" != "$HASH_AFTER" ] && echo "Graph changed"
```