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@ai-billing/lago
@ai-billing/lago / LagoDestinationOptions

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Interface: LagoDestinationOptions<TTags>

Defined in: lago-destination.ts:24 Options for createLagoDestination. Lago ingests metered usage as events tied to an external_customer_id plus a code (billable metric code). This destination extracts identity from billing event tags, builds default properties 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.

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Type Parameters

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TTags

TTags extends DefaultTags = DefaultTags The shape of the tags object, extending DefaultTags.

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Properties

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apiKey

apiKey: string
Defined in: lago-destination.ts:28 Lago API key used for Authorization: Bearer ....

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apiUrl?

optional apiUrl?: string
Defined in: lago-destination.ts:30 Base URL for the Lago API. Defaults to https://api.getlago.com.

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meterCode?

optional meterCode?: string | ((event) => string)
Defined in: lago-destination.ts:36 Lago billable metric code (event.code), or a function that derives the code from the billing event. Defaults to 'llm_usage'.

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externalCustomerIdKey?

optional externalCustomerIdKey?: keyof TTags
Defined in: lago-destination.ts:42 Tag key used to read the Lago external_customer_id. When omitted, common tag keys are checked: userId, externalCustomerId.

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mapMetadata?

optional mapMetadata?: (event) => Record<string, string | number | boolean>
Defined in: lago-destination.ts:54 Optional override for the properties payload sent to Lago. 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 properties from event.cost via non-null assertion. Missing BillingEvent.cost is not supported and will throw when converting.

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Parameters

event
BillingEvent<TTags>

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Returns

Record<string, string | number | boolean>