---
title: "Billing and limits"
description: "Fund API usage, configure spend alerts, and understand the capacity applied to requests."
icon: "credit-card"
---
API Platform billing is organization-wide. The organization's available balance funds
billable Production requests across its projects. Manual purchases add funding to that balance,
and purchase records preserve the funding history. Members with billing management permission can
buy credits and manage payment and tax details.
Manage organization funding, payment details, purchase history, and automatic top-up.
## Request charges
Token-priced requests reserve **$1 of prepaid balance** before dispatch. Once a non-streaming
response or terminal streaming event provides validated usage, the API Platform settles the
actual token charge and releases unused funds. The reservation is not an extra fee, an estimate,
or a maximum charge.
If output was delivered but final usage evidence is missing, the reserved balance remains held
while the charge is reconciled. The API Platform does not cancel that hold or substitute
guessed usage. Each request in a Responses tool loop is charged separately.
See [Pricing](/developers/pricing) for model rates and a worked example.
## Automatic top-up
After an eligible Production request reserves funding, automatic top-up checks the remaining
available balance. If it is below the chosen threshold, automatic top-up begins a purchase for the
configured funding amount. Insufficient balance is handled separately, so enabling automatic top-up
does not guarantee that an underfunded request can continue. A daily maximum limits how many
automatic top-ups can begin in one UTC day, and a saved default payment method is required before
automatic top-up can be enabled.
## Monthly budget
A monthly budget compares the organization's estimated calendar-month spend with a chosen amount.
When a check detects a newly reached threshold, it sends an email for the highest reached threshold:
50%, 75%, or 100%. If spend passes more than one threshold between checks, lower skipped thresholds
do not send separate emails.
:::warning
A budget is an alerting threshold, not a spending cap. Requests can continue after estimated spend
reaches or exceeds it.
:::
Budget spend is an operational estimate. Use billing records and invoices as the record of charges.
Manage the monthly alerting budget and review period-to-date estimated spend.
## Request capacity
API traffic is subject to capacity assigned to the organization and project. Capacity can
come from the organization's usage tier, an enterprise contract, or an explicit override.
- **Request rate** limits total requests over a time window.
- **Operation throughput** limits related capabilities or a specific model operation.
- **Input and output token rates** limit measured-token traffic.
- **Project overrides** can lower the organization request-rate, input-token, or output-token ceiling
for a project; they do not increase an organization ceiling.
A model without its own ceiling uses the broader applicable capability or organization limit.
Several independently enforced ceilings can apply to the same request. A capacity rejection's
headers identify the scope and dimension that rejected it.
Review organization capacity, project overrides, capability limits, model limits, and token rates.
See [Errors and debugging](/developers/guides/errors-and-debugging) for `429` handling and
[API pricing](/developers/pricing) for billing models.