Payments and billing: who processes your card, and how credits are metered
Two payment paths, both hosted by the processor. Monthly plans are sold through Clerk Billing; one-time credit packs go through a Stripe Checkout session. In both cases the card is entered on the processor's own page, so card numbers never reach our servers and there is nothing card-shaped in our database to leak.
The two payment paths
| What you're buying | Processed by | How |
|---|---|---|
| A monthly plan (Lite / Starter / Scale / Agency) | Clerk Billing | Subscription; a webhook grants that plan's monthly credits |
| A one-time credit top-up | Stripe | A hosted Stripe Checkout session |
How we know a payment succeeded
Credit grants are driven by webhooks from the processor rather than by the browser returning to a success page — a success URL can be visited by hand, a signed webhook cannot be forged. The Stripe webhook signature is verified against the raw request body before anything is credited, and the purchased pack is resolved from our own price table rather than from the URL, so an edited link cannot inflate what gets granted.
What a credit is
- Usage-based, not seat-based. A credit maps to real underlying model and tool cost, so an expensive model costs proportionally more than a cheap one.
- Monthly credits reset at the start of each period rather than rolling over.
- Reads are free — you spend credits when a task runs, not when the agent looks at data.
- Dashboard refreshes cost nothing, because they replay queries with no model in the loop.
- The free tier is real and recurring — 2,500 credits every month, no card required to start.
Spend protection
On an enforced plan, a run is blocked when the balance reaches zero rather than silently continuing and invoicing you later. Model prices are also checked against the live gateway catalogue on each call rather than a hand-typed table, so a provider price change doesn't quietly mis-meter your usage — a discipline that caught a real 30x fallback mis-rate before it billed anyone, described in the GPT-5.6 Luna default-model post.
Frequently asked questions
- Who processes payments for Agent Planners?
- Monthly plans are sold through Clerk Billing and one-time credit top-ups through Stripe Checkout. Both are hosted by the processor, so card details are entered on their pages, not ours.
- Do you store my credit card details?
- No. We never render a card field — payment happens on the processor's hosted checkout, so no card data reaches our servers or database.
- Do I need a credit card to try it?
- No. The free tier is 2,500 credits every month, recurring, with no card required.
- Do unused credits roll over?
- No — monthly plan credits reset at the start of each period. One-time top-up packs are separate from the monthly allotment.
- Can I be charged unexpectedly for overage?
- On an enforced plan a run is blocked when your balance reaches zero rather than continuing and billing you afterwards.