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

# Storage: Track progress

> Tracks the progress of a data synchronization.

Records how far a data synchronization has got, so a later run can pick up where this one left off. For each record passing through, it reads an identifier and a date from your data and marks that identifier as finished at that date in the storage. Pair it with [Storage: Load progress](/references/transformer/storage-tracker-load-from-storage), which reads this progress back at the start of the next run, to build a flow that only processes new or changed records. The data flowing through your transformation is passed along unchanged.

This documentation describes: [Schema](/schemas/transformer/storage-tracker-save-in-storage)

## Fields

**Storage**

Required

The storage to record progress in. Point the [Storage: Load progress](/references/transformer/storage-tracker-load-from-storage) transformer at the same storage to read it back. See [Storage](/references/storage) for how to set one up.

See the [storage](/references/storage) reference.

**Path to date**

Required

The path to the date in your data to record as the progress point, for example `updated_at`. This date must already be present in the data, otherwise the run stops with an error. Supports [placeholders](/references/placeholders).

**Path to entity identifier**

Required

The path to the identifier in your data to mark as processed, for example `id`. Supports [placeholders](/references/placeholders).

**Date format**

Optional

The format the date at the path above is written in, so it can be read correctly, for example `Y-m-d\TH:i:sP`. Leave it empty to have the format detected automatically. See [the PHP date formats reference](https://www.php.net/manual/datetime.formats.php) for the available format codes.

## Sample data

This transformer writes progress into a configured storage and passes your data through unchanged, so it has no before/after of its own to show. The example below shows a typical configuration: for each record, the identifier at `id` is marked as processed at the date read from `updated_at`. A later [Storage: Load progress](/references/transformer/storage-tracker-load-from-storage) run pointed at the same storage would then report that identifier and date as the resume point.

| Field | Value |
| - | - |
| Storage | A configured storage |
| Path to date | `updated_at` |
| Path to entity identifier | `id` |
| Date format | (empty, detected automatically) |

```json Configuration theme={null}
{
  "prototype": "storage-tracker-save-in-storage",
  "parameters": {
    "tracker": { "prototype": "storage", "parameters": {} },
    "datePath": "updated_at",
    "identifierPath": "id"
  }
}
```


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