> For the complete documentation index, see [llms.txt](https://merithic.gitbook.io/merithic-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://merithic.gitbook.io/merithic-docs/api-reference/overview.md).

# Overview

The Updatr API is what your product talks to at runtime: to check a license, find out whether an update exists, and fetch it.

## Base URL

```
https://api.merithic.com
```

Clean paths map to the Updatr API, so `/check` reaches the check endpoint. All responses are JSON.

## Who calls what

| Caller                                     | Endpoints                                                                                                                                                                                                                                                  |
| ------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Your product**, running in a Roblox game | [`/check`](/merithic-docs/api-reference/endpoints/check.md), [`/unlock`](/merithic-docs/api-reference/endpoints/unlock.md), [`/version`](/merithic-docs/api-reference/endpoints/version.md), [`/update`](/merithic-docs/api-reference/endpoints/update.md) |

## The three identifiers

Nearly every call carries these:

| Field        | What it is                                 |
| ------------ | ------------------------------------------ |
| `user_id`    | The Roblox user ID of the player.          |
| `product_id` | Your product's ID, shown in the dashboard. |
| `key`        | The buyer's license key, unique to them.   |

The key is what ties a running copy to a specific buyer. If a key shows up under a different user ID than the one it was issued to, that's recorded as a security alert on your dashboard.

## Don't trust the response on its own

{% hint style="danger" %}
[`/check`](/merithic-docs/api-reference/endpoints/check.md) returns a plain `{ success: true }`. That is a convenience, **not** a security boundary. Anyone can stub an HTTP call to return `true`.

For anything worth protecting, use [`/unlock`](/merithic-docs/api-reference/endpoints/unlock.md). It returns an encrypted payload your product must decrypt with the buyer's key. A faked response yields no payload, so the product simply doesn't run.
{% endhint %}

## Rate limits and outages

Requests are rate-limited per studio. If Updatr is in maintenance, endpoints return `503` with `{ "error": "outage_mode" }`. Handle that by failing open or closed depending on how strict you want to be.

## Next

New to this? Start with the walkthrough — it covers licensing and auto-update in the order you'd actually build them, with the failure modes spelled out.

{% content-ref url="/pages/f90FMPoRVaO9Wlfru9Sn" %}
[Integrating step by step](/merithic-docs/api-reference/integrating.md)
{% endcontent-ref %}

{% content-ref url="/pages/S0X7YMCTSVavUo5g7UNs" %}
[Endpoints](/merithic-docs/api-reference/endpoints.md)
{% endcontent-ref %}


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