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

# OpenMeter

> Report attributed cloud spend to an OpenMeter meter, including on Kong Konnect

CostGraph reports each customer's attributed cloud spend to an
[OpenMeter](https://openmeter.io) meter as CloudEvents. OpenMeter aggregates
them per subject for your billing system or its own billing to price. The
shared model, tag rules, and nightly behavior are on the
[Billing exports](/costgraph/integrations/exports/overview) page.

OpenMeter is also the metering behind Kong Konnect. A Konnect account
connects the same way, with a different API URL.

## Before you begin

* Create a meter with a **sum** aggregation whose value property is `$.value`.
  CostGraph reports against its event type.
* Price per cent, or divide by 100 downstream.
* Copy an API token from your OpenMeter settings. On Kong Konnect, use a
  personal access token, which starts with `kpat_`.

## Connect

<Steps>
  <Step title="Connect the account">
    In **Integrations**, click **OpenMeter** and enter the API token. Leave
    **API URL** empty for OpenMeter Cloud. For anything else, set it to the API
    root including its version, not only the host:

    * Self-hosted: your instance URL ending in `/api/v1`
    * Kong Konnect: `https://{region}.api.konghq.com/v3/openmeter`, with the
      region of your Konnect organization

    CostGraph verifies the token before it saves anything, and stores it
    encrypted.
  </Step>

  <Step title="Bind a meter">
    Bind an `openmeter_` tag key to one of your meters. CostGraph lists meters
    by event type.
  </Step>
</Steps>

## Tag spend by customer

The tag value must be an OpenMeter subject, the identifier for whoever the
usage belongs to. OpenMeter creates a subject the first time it sees one, so a
mistyped tag value becomes a new metered subject. Check the tag's values before
you bind the meter, and review what was reported after any rule change.

## Event payload

Each customer-day is one CloudEvent. Its `source` is `costgraph`, its `type`
is the meter's event type, and its `subject` is the tag value. The event
`id` is derived from the day and the totals, so a retried run is deduplicated.
The data carries `value`, the amount in cents, and the shared reconciliation
fields.

Corrections are sent as the difference and can be negative. The meter must
sum `$.value` for the total to settle.

## OpenMeter behavior

Each event is timestamped with the day it belongs to. A correction lands in
that day's window, not the day it was sent.