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CostGraph reports each customer’s attributed cloud spend to a Lago billable metric as usage events. A charge on the metric turns them into invoices. The shared model, tag rules, and nightly behavior are on the Billing exports page.

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Before you begin

  • Create a billable metric that aggregates value with a sum. CostGraph offers only metrics it can see in the connected account.
  • Attach a charge to the metric. Price per cent, or divide by 100 in the metric.
  • Copy an API key from Developers > API keys.

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Connect

1

Connect the account

In Integrations, click Lago and enter the API key. If you self-host Lago or use a region other than the default, set API URL to your instance, for example https://lago.internal. Leave it empty for Lago Cloud. CostGraph verifies the key against Lago before it saves anything, and stores it encrypted.
2

Bind a billable metric

Bind a lago_ tag key to one of your billable metrics.

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Tag spend by customer

The tag value must be a Lago external subscription id, not a customer id. Lago attributes usage to a subscription, so a customer with two subscriptions needs the tag to name the one that carries the cloud spend. Lago rejects an event for a subscription that doesn’t exist, and CostGraph records the day with the rejection instead of billing it.

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Event payload

Each customer-day is one event on the metric. Its transaction_id is derived from the day and the totals, so a retried run counts once. The properties carry value, the amount in cents, and the shared reconciliation fields. Corrections are sent as the difference and can be negative. The metric must sum value for the total to settle.

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Lago behavior

Lago assigns an event to the period its timestamp falls in. A correction that arrives while that period’s invoice is a draft is included in it. After the invoice is finalized, Lago doesn’t move the event to a later one. Settle the difference with a manual adjustment in Lago.