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

> ## Agent Instructions
> Automate.ax automations are TypeScript programs.
> Use Bun for installation and command examples.
> Use Automate.ax for the product name and automate.ax for the package, CLI, and domain.
> Treat documented public APIs as current; do not invent transitional or deprecated names.

# Tag subscriber by email

> Applies a tag to an existing subscriber by email address.

`kit.tagSubscriberByEmailAddress` applies a tag to an existing subscriber by email address.

```ts automations/tag-subscriber-by-email-address.automation.ts theme={null}
import { automation, markSignificant } from "automate.ax"
import { kit } from "automate.ax/kit"

export default automation("Tag subscriber by email", () => {
  markSignificant(
    kit.tagSubscriberByEmailAddress({
      tagId: 1,
      emailAddress: "value",
    }),
  )
})
```

## Input

Pass these fields:

| Field          | Type      | Required | Description |
| -------------- | --------- | -------- | ----------- |
| `tagId`        | `integer` | Yes      | —           |
| `emailAddress` | `string`  | Yes      | —           |

## Output

Returns an object with these fields:

| Field        | Type     | Required | Description |
| ------------ | -------- | -------- | ----------- |
| `subscriber` | `object` | Yes      | —           |

Kit rate limits OAuth connections to 600 requests per 60 seconds and V4 API keys to 120 requests per 60 seconds. Automate.ax honors provider retry timing for rate-limit and temporary bulk-capacity responses.