> ## 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.

# OpenMeterDestinationOptions

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

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[@ai-billing/openmeter](/docs/sdk/ai-billing/reference/openmeter/typedoc/index) / OpenMeterDestinationOptions

# Interface: OpenMeterDestinationOptions\<TTags>

Defined in: [openmeter-destination.ts:24](https://github.com/narevai/ai-billing/blob/main/packages/openmeter/src/destination/openmeter-destination.ts#L24)

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

OpenMeter ingests usage as CloudEvents where the event `type` identifies the meter and the `subject`
identifies the customer. This destination extracts identity from billing event tags, builds default
`data` from the event (usage + tags), and always sets `cost_nanos` and `currency` from
BillingEvent.cost. Callers must supply a defined `cost` on each event; the implementation
asserts it is present and may throw at runtime if it is omitted.

## Type Parameters

### TTags

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

The shape of the tags object, extending DefaultTags.

## Properties

### apiKey

> **apiKey**: `string`

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

OpenMeter API key.

***

### apiUrl?

> `optional` **apiUrl?**: `string`

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

OpenMeter API base URL. Defaults to '[https://eu.api.konghq.com](https://eu.api.konghq.com)'.

***

### eventType?

> `optional` **eventType?**: `string`

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

OpenMeter metering event type (CloudEvents `type`).

Defaults to `'llm_usage'`.

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### customerIdKey?

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

Defined in: [openmeter-destination.ts:42](https://github.com/narevai/ai-billing/blob/main/packages/openmeter/src/destination/openmeter-destination.ts#L42)

Tag key used to read the OpenMeter customer identifier (CloudEvents `subject`). When omitted, common
tag keys are checked: `openMeterCustomerId`, `userId`.

***

### mapMetadata?

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

Defined in: [openmeter-destination.ts:54](https://github.com/narevai/ai-billing/blob/main/packages/openmeter/src/destination/openmeter-destination.ts#L54)

Optional override for the `data` payload sent to OpenMeter.

When omitted, metadata is built from buildMeterMetadata and includes:

* token/usage dimensions
* `tag_*` values from event tags

Note: this destination always merges `cost_nanos` and `currency` into `data` from `event.cost` via
non-null assertion. Missing BillingEvent.cost is not supported and will throw when converting.

#### Parameters

##### event

`BillingEvent`\<`TTags`>

#### Returns

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