> For the complete documentation index, see [llms.txt](https://docs.graspil.com/en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.graspil.com/en/app/start-utm.md).

# Processing start parameters (UTM)

## **What is the start parameter?**

The start parameter is the only way to pass data to the bot when it's launched. To use it, you need to add the string `?start={ your data }` to a regular bot link — such links are called Deep links.

You can use it to build a referral program or add parameters for tracking user sources. You can read more about tracking in our [blog](https://graspil.com/ru/post/utm_for_telegram_bot).

<details>

<summary>How do I get this data in the bot?</summary>

Example bot link: `https://t.me/Graspil_bot?start=docs`

The value the bot receives: `docs`

When the user launches the bot, you receive an [Update](https://core.telegram.org/bots/api#update) of type\
[Message](https://core.telegram.org/bots/api#message). It contains a `text` parameter equal to `/start`; in the case of a deep link, the `text` parameter will equal `/start docs`

**Example**

{% code overflow="wrap" lineNumbers="true" %}

```json
{
   update_id":10000,
   "message":{
     "date":1441645532,
     "chat":{
        "last_name":"Test Lastname",
        "id":1111111,
        "first_name":"Test",
        "username":"Test"
     },
     "message_id":1365,
     "from":{
        "last_name":"Test Lastname",
        "id":1111111,
        "first_name":"Test",
        "username":"Test"
     },
     "text":"/start docs" // <----- data passed in start
   }
}
```

{% endcode %}

</details>

{% hint style="info" %}
There's a 64-character limit on the length of the string in the start parameter
{% endhint %}

### How does graspil handle the start parameter?

Graspil uses this parameter to [track user sources](https://graspil.com/ru/post/utm_for_telegram_bot). Telegram doesn't support additional parameters, so we've added the ability to configure how this parameter is processed.

Since start can only carry a single string, we've added rules that let you split such a string into separate parameters.

For example, you need to pass the referral source and the source type (e.g. email). To do this, you can use a string like `start=source-news1_medium-email` and set up the appropriate processing rules.

In graspil, all such parameters are converted into `parameter=value` pairs — in other words, into a table that you can then work with (build reports, filter data).

| Parameter | Value |
| --------- | ----- |
| source    | news1 |
| medium    | email |

{% hint style="info" %}
You can read about how to configure start parameter processing in the [next section](/en/app/start-utm/configuring-start.md)
{% endhint %}