Pricing calculator
Estimate your monthly bill.
Tell us your expected volume and which AI features you'd use. We'll show the real math — base plan, included credits, and any metered overflow.
Your setup
AI features
Pro plan recommended
Estimated monthly bill
$19.00
/month
$19 Pro plan · $0.00 metered
Breakdown
The 500 included credits on Pro are allocated proportionally across enabled features. Anything above is metered at cycle end.
Calculator FAQ
The math behind the numbers.
What counts as a submission? +
One successful POST to your endpoint that passes validation.
Rejected requests — bots, invalid fields,
honeypot
trips — don't
count. You only pay for data that actually lands in your inbox.
Do I need AI features to use Postbox? +
Not at all. Core features — validation, standard spam protection, webhooks, Discord, Slack, the REST API, and
MCP access
— work without
spending a single credit. AI features are entirely optional toggles
you enable per form when you need them.
Can I change my plan mid-cycle? +
Yes. Upgrade anytime and get immediate access to Pro features.
Downgrade at cycle end and keep all your data. If you have more
than one form, you'll pick which one stays active on Free.
What happens if I go over my included credits? +
We don't cut you off. Extra usage is metered at the per-action rates
shown above and billed at the end of your cycle. Most users stay well
within their 500 included credits. If you consistently exceed them,
reach out — we can discuss volume pricing.
Is there a free trial for Pro? +
The Free plan is effectively an unlimited trial. You get full
functionality — forms, submissions, validation, destinations, API
access — up to 5,000 lifetime submissions. Upgrade to Pro when you
need more volume or AI features.