# Verifying Store Integrity

This guide explains how to **verify the internal integrity** of an EventSourcingDB instance. It covers how to trigger a **full validation of stored events and indexes** and how to interpret the results.

## Overview

EventSourcingDB provides a **verification endpoint** that performs a **complete integrity check** of the event store. It **recalculates all event hashes** from scratch, **validates the consistency of stored data**, and **verifies all internal indexes**.

This operation can help detect **data corruption**, **storage issues**, or **index inconsistencies**.

## Running a Store Verification

To start a store verification, send an HTTP **`POST`** request to **`/api/v1/verify-store`**:

```shell
curl -i \
  -X POST \
  -H "Authorization: Bearer <API_TOKEN>" \
  http://localhost:3000/api/v1/verify-store
```

The server responds with a **stream of newline-delimited JSON**. While the verification is still running, the server sends **[`heartbeat` lines](/learn/tutorials/first-steps-with-eventsourcingdb/observing-events)** to keep the connection open; the **final line carries the result**:

```json
{"type":"result","payload":{"errors":[],"warnings":[]}}
```

An empty `errors` list indicates that **no inconsistencies were found**. The `warnings` list may contain **additional notices**, but does not necessarily indicate a failure.

If the verification itself cannot run to completion – say the store cannot be read – the stream ends with an `error` line instead:

```json
{"type":"error","payload":{"error":"..."}}
```

The status code is already **200** by the time the first line goes out, so **the last line is what tells you whether the verification finished**. Treat an `error` line as an aborted check, not as a clean one.

## Typical Use Cases

Store verification is useful in the following scenarios:

- **After recovering** from disk failures or system crashes.
- As part of **regular maintenance procedures**.
- **Before migrating data** to a new instance.
- To investigate **unexpected read or write issues**.

A successful store verification provides assurance that the event store is **internally consistent and fully operational**.

> **Impact on Performance**
>
> Running a full store verification can be **resource-intensive, especially for large datasets**. It is recommended to perform this operation during **maintenance windows** or **low-traffic periods**.