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

# Usage and Billing

> Keys, spend caps, failed requests, and funding.

#### What does an API key look like?

It starts with `z_sk_`. The `nito_cli_` and `nito_mcp_` prefixes belong to the CLI and MCP surfaces. See [Authentication](/api/get-started/authentication).

#### Was I charged for a failed request?

No. The reservation is released when a request fails before producing usage. See [Check usage](/api/get-started/check-usage).

#### Where do I see my usage?

In the [developer console](https://app.trynito.ai/api): spend for the selected window, request count, token totals, spend by model, and a daily breakdown. Per-call usage is in every response's `usage` block.

#### Can I cap what a key spends?

Yes. A daily, monthly, or overall spend cap, set at creation; the key stops working when it is reached. Keys have no per-feature scopes; roles limit who manages them.

#### How do I fund API access?

API access is prepaid. Add funds from the Billing page at app.trynito.ai. See [Plans](/plans) and [Pay with crypto](/plans/pay-with-crypto).

#### Does a subscription cover the API?

Subscription allowance applies to API calls first, and prepaid funds cover the rest. Free accounts have no API allowance; an API key needs a subscription or a prepaid balance. See [Plans](/plans).

## Related

* [Authentication](/api/get-started/authentication)
* [Check usage](/api/get-started/check-usage)
* [Errors and limits FAQ](/help/api/errors-and-limits)

#### Can I read my balance through the API?

Yes. Use [`GET /api/v1/billing/balance`](/api/api-reference/usage/get-balance) with an admin-enabled API key owned by a current organization owner or admin. It returns amounts as integer USD nanos strings. The endpoint does not provide usage history.


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