---
title: Set allowance periods and anchors
description: Align daily or monthly product-user allowances with a subscription start date.
---

Configure the allowance amount and period on the inference key's cap. Set `allowance_starts_at` on the product user when your subscription cycle differs from UTC calendar periods.

## Choose the period

Without an anchor, daily caps use UTC calendar days and monthly caps use UTC calendar months. With an anchor, daily periods use consecutive 24-hour windows and monthly periods use calendar anniversaries at the anchor's UTC time. Lifetime caps have no repeating window.

A monthly anchor of July 17 produces a September 17 to October 17 window on September 30. The anchor does not make all usage since July count in September. For days absent from a month, Zorveus uses that month's final day and returns to the original anchor day when possible.

## Pass the subscription anchor

Use a server-owned subscription timestamp in RFC 3339 format. For inference, send the header or body metadata:

```python
response = await client.chat.completions.create(
	model=model_id,
	messages=[{"role": "user", "content": "Hello"}],
	extra_headers={
		"X-Zorveus-External-User-ID": user_id,
		"X-Zorveus-Allowance-Starts-At": "2026-07-17T09:00:00Z",
	},
)
```

The body alternative is `metadata.product_user.allowance_starts_at`. Body metadata takes precedence over the header. For multipart requests, use the same header or a JSON-encoded `metadata` form field.

Omit the anchor to preserve the stored value. Repeating the same value is allowed. A timestamp older than the stored anchor is rejected. Future timestamps are rejected. Clear the anchor through management with an explicit `null`, not an inference request.

Do not set the anchor to the current time on every request. That changes the period instead of tracking the subscription cycle.

## Read the current window

Read `allowance.period_start` and `allowance.period_end` in the [product-user response](/startups/check-allowance). Do not calculate a separate frontend reset date.

The anchor is app-scoped for the product user, not separate for each plan key. Usage in the current window can span connections. Credit-grant expiration is independent of the allowance anchor.