Pay-As-You-Go Overflow
Keep coding past your Halfbill Code monthly allowance with an opt-in credits balance
By default a Halfbill Code plan is a hard cap: once the monthly allowance is fully used, requests are rejected until renewal. Pay-as-you-go overflow is an opt-in on the Halfbill Code Usage page that keeps requests flowing past the allowance — extra usage bills a credits balance at the regular per-token prices, with the same API key and the same coding agents. The Usage page also carries the full allowance meters, the weekly premium allowance, Reset Passes, and the model usage chart.
Overflow is off by default — until you enable it, nothing ever charges past your subscription price. It never touches your plan allowance either: credits cover only usage the plan itself wouldn't serve — spend past the monthly pool, and premium usage past the weekly cap.
When overflow applies
| Situation | Overflow off (default) | Overflow on |
|---|---|---|
| Within the monthly allowance | Plan credits | Plan credits |
| Monthly allowance exhausted | Requests rejected with 402 | Requests bill your credits balance |
| Weekly premium cap hit, allowance remaining | Reset Pass or wait | Premium models bill your balance |
| Weekly premium cap hit, allowance exhausted | Requests rejected with 402 | Premium models bill your balance |
| Credits balance empty | — | Requests rejected with 402 |
The weekly premium fair-use cap limits what the plan allowance pays for, not what your own balance can: with overflow on and a positive balance, premium requests past the cap keep flowing and bill your credits at per-token prices, while standard models keep drawing from the monthly allowance as usual. A Reset Pass is still the way to keep that premium spend inside your already-paid plan allowance instead of on the balance. Once the monthly pool itself is gone, overflow covers everything.
If the allowance runs out with overflow off (or with an empty balance), the API's 402 says what to do:
{
"error": {
"message": "Dev Plan credit limit reached. Upgrade your plan or wait for renewal on 8/24/2026. Or enable pay-as-you-go overflow in your Halfbill Code dashboard to keep going past your allowance.",
"type": "invalid_request_error",
"code": "billing_error"
}
}Topping up
Enable overflow on the Usage page, pick a preset ($10, $25, $50, $100) or a custom amount between $10 and $5,000, and Top up — the charge goes to the card already backing your Halfbill Code subscription, with no checkout redirect. Usage itself is metered at the regular per-token prices. Each top-up emails a PDF invoice and appears in your billing history.
Top-ups are idempotent end to end: a double-click or a retried request reuses the same charge instead of creating a second one.
Auto-reload
Turn on Auto-reload and the balance refills itself: when it falls below your threshold ($5–$1,000), your reload amount ($10–$5,000) is charged to the saved card automatically.
Guardrails worth knowing:
- Disabling overflow always disables auto-reload — you can never buy credits you cannot spend.
- Failed auto-reload charges back off exponentially (1h doubling up to 24h), and auto-reload switches itself off after 7 days of continuous payment failures.
Overflow is available on every Halfbill Code tier. If you find yourself covering a lot of usage from the balance every cycle, a tier upgrade is usually the better deal: plan allowances are worth more than the subscription price ($40 of usage for $25 on Code Starter), while overflow bills at the regular per-token prices. Compare on the pricing page.
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