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

# PolarDestinationOptions

[**@ai-billing/polar**](../index)

***

[@ai-billing/polar](/docs/sdk/ai-billing/reference/polar/typedoc/index) / PolarDestinationOptions

# Interface: PolarDestinationOptions\<TTags>

Defined in: [polar-destination.ts:19](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L19)

Options for [createPolarDestination](/docs/sdk/ai-billing/reference/polar/typedoc/functions/createPolarDestination).

Polar ingests events keyed by a `customerId` (and optionally an `externalId`) plus a metadata map. This
destination extracts identity from billing event tags, builds default metadata from the event (usage +
tags), and includes cost when present.

## Type Parameters

### TTags

`TTags` *extends* `DefaultTags` = `DefaultTags`

The shape of the tags object, extending DefaultTags.

## Properties

### client?

> `optional` **client?**: `Polar`

Defined in: [polar-destination.ts:26](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L26)

Optional pre-configured Polar SDK client. When omitted, a client is constructed from `accessToken` and
`server`.

***

### accessToken?

> `optional` **accessToken?**: `string`

Defined in: [polar-destination.ts:28](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L28)

Access token used when creating a Polar SDK client.

***

### server?

> `optional` **server?**: `"sandbox"` | `"production"`

Defined in: [polar-destination.ts:30](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L30)

Polar environment used when creating a Polar SDK client.

***

### eventName

> **eventName**: `string` | ((`event`) => `string`)

Defined in: [polar-destination.ts:36](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L36)

Event name to ingest into Polar, or a function that derives the name from the billing event.

Use a function when you want different Polar events per model/provider while keeping one destination.

***

### customerIdKey?

> `optional` **customerIdKey?**: keyof `TTags`

Defined in: [polar-destination.ts:41](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L41)

Tag key used to read the Polar `customerId` (internal ID). When omitted, common tag keys are checked:
`customerId`, `polarCustomerId`, `customer_id`.

***

### externalCustomerIdKey?

> `optional` **externalCustomerIdKey?**: keyof `TTags`

Defined in: [polar-destination.ts:46](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L46)

Tag key used to read the Polar `externalId`. When omitted, common tag keys are checked: `userId`,
`externalId`, `user_id`.

***

### mapMetadata?

> `optional` **mapMetadata?**: (`event`) => `Record`\<`string`, `string` | `number` | `boolean`>

Defined in: [polar-destination.ts:56](https://github.com/narevai/ai-billing/blob/main/packages/polar/src/destination/polar-destination.ts#L56)

Optional override for the metadata payload sent to Polar.

When omitted, metadata is built from buildMeterMetadata and includes:

* token/usage dimensions
* `tag_*` values from event tags
* `credits_consumed` / `cost_currency` when `event.cost` is present

#### Parameters

##### event

`BillingEvent`\<`TTags`>

#### Returns

`Record`\<`string`, `string` | `number` | `boolean`>