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

# Understand usage and billing

> Find credit usage, distinguish validation from delivery, and investigate charges.

Credits belong to your organization. Check **Usage** for processing records and **Organization** → **Billing** for the owner's subscription and billing controls. Plan entitlements and available limits are shown by the account; they may differ between preview and production.

## When credits are used

| Operation                           | What to expect                                                        |
| ----------------------------------- | --------------------------------------------------------------------- |
| Template/modal authoring validation | No message credits; authoring rate limits apply                       |
| Compile                             | A metered operation even though no Slack message is posted            |
| Send                                | Metered delivery through the connected Slack app                      |
| Bulk send                           | Inspect each destination's result and associated usage                |
| Create or edit a schedule           | Credits are used when delivery occurs                                 |
| Push events into a digest           | Credits are used per delivered batch according to queue configuration |
| Destination test                    | No message credit, but a real receiver request                        |
| Tracked link click                  | No additional message credit                                          |

Use returned usage fields and the credit log to determine the outcome of a particular request. Do not infer a charge or refund solely from an HTTP timeout: the server may have processed the request before the connection ended.

## Avoid accidental duplicate operations

Preserve the same idempotency key and request body when retrying one intended send. Starting a new operation with a new key can create another message and another charge. Bulk responses can contain failures alongside successes; retry only the intended failed work after reconciling its outcome.

## Limits and billing questions

A `tier_limit` error indicates a plan restriction; `insufficient_credits` indicates the available credit/overage policy prevented processing. They require different remedies. Check the response and account settings before changing the workflow.

For a billing discrepancy, send support the environment, request ID, timestamp, and relevant usage entry. Do not include API keys or card information. See [Limits](/guides/limits) and [Logs](/guides/logs).