Does InboxPolicy Have a Free Plan?

By Aria Pramesi, founder of InboxPolicy · Updated July 9, 2026

No. InboxPolicy has no free plan and no free tier, a deliberate choice since free tiers attract list-cleaning abuse. The $0.01 per-call x402 price is the trial itself, no account or API key required. Eligible eligible cache hits for the same normalized address and strictness within 72 hours when force_refresh is false and malformed-email rejection can cost 0 credits. API-key replay is separate and limited to the idempotency record TTL; x402 has no replay wrapper.

Why doesn't InboxPolicy have a free tier?

Free verification tiers get abused for one-time list cleaning: someone signs up, burns the free batch checking a scraped list, and never becomes a customer. InboxPolicy skips that trade entirely. There is no free plan and no free tier on any pricing page.

Instead the entry price is $0.01 per fresh verification, paid per call via the x402 protocol using USDC on Base. No account, no API key, no signup form to abuse.

What's actually free on InboxPolicy?

Two result types can cost 0 credits:

• Cache re-verification within 72 hours: an eligible re-check of the same normalized address and strictness inside that window with force_refresh false returns from_cache and bills 0 credits.
• Malformed-email rejection: addresses that fail syntax checks are rejected before they ever reach SMTP, so they cost 0 credits.

These aren't a separate free tier, they apply to every call on every plan.

How does the $0.01 per-call trial work?

There's no separate trial product. The x402 flow itself is the trial: a keyless request to the API returns an HTTP 402 status with machine-readable payment requirements. The calling agent pays $0.01 in USDC on Base via a PAYMENT-SIGNATURE header, then receives its send-decision plus an on-chain settlement receipt.

For agent-native use there's also an MCP server exposing decide_send, verify_email, batch tools, and usage, plus a REST API with idempotency keys, per-item batch results, async batches up to 50,000 emails, and signed completion webhooks.

For non-x402 use, prepaid credit packs are available by card: Starter $5 for 1,000 credits, Builder $19 for 5,000, Growth $79 for 25,000.

How does this compare to ZeroBounce's 100 free verifications a month?

ZeroBounce offers 100 free verifications a month plus a marketing dashboard and a spam-trap/abuse database, at roughly $9.90 per 1,000 on subscription (or $19.50 pay-as-you-go) after that. InboxPolicy has no equivalent free monthly allotment, since its model is pay-per-call from the first request.

The trade-off: ZeroBounce's free tier suits occasional, small-volume checking through a dashboard. InboxPolicy's per-call pricing suits agents making send or no-send decisions programmatically, where a fixed $0.01 cost per fresh check and no signup step matter more than a monthly free allowance.

Credit packs vs pay-per-call: which is cheaper?

If you're not using x402, prepaid packs lower the per-verification cost as volume grows: Starter is $5.00 per 1,000, Builder drops to $3.80 per 1,000, Growth drops to $3.16 per 1,000. Volume pricing is available on request beyond that.

Compare that to the $0.01 per-call x402 rate, which works out to $10.00 per 1,000 if paid one call at a time. Credit packs exist for callers who want a lower blended rate without wiring per-call crypto payments into every request.

When should I use a tool with a free tier instead?

InboxPolicy isn't built for every case. Use MillionVerifier for one-shot cleaning of a huge scraped list at the lowest cost. Use ZeroBounce when spam-trap and abuse-address detection matters more than send-decision automation. Use Kickbox or Emailable for a dashboard-first workflow built around CSV uploads rather than an API or agent integration.

InboxPolicy fits when the caller is an agent or pipeline that needs a send or no-send action with evidence, not a person cleaning a list by hand.

What free actually gets you

People searching "free email verification api" or "free email checker" usually want an honest answer, not a redirect to a pricing page. So here's a survey of what's actually free in this market, as of July 2026, with the trade-offs that come attached. Full sourcing and pricing detail for each is on the linked comparison pages.

• ZeroBounce: 100 free verifications/month, ~$9.90/1,000 subscription or ~$19.50/1,000 pay-as-you-go after that. See InboxPolicy vs ZeroBounce.
• Hunter: 50 credits/month free, shared between email search and verification, so the free allotment isn't dedicated to verification alone. See InboxPolicy vs Hunter.
• Clearout: 100 free credits on signup, no card required. See InboxPolicy vs Clearout.
• Truelist: 200 free validations plus 10 enhanced-validation credits on new accounts, no card required. See InboxPolicy vs Truelist.
• MillionVerifier: maintains a standing free tier, then roughly $3.90-$0.45/1,000 from entry to 1M volume, the cheapest paid tier at high volume. See InboxPolicy vs MillionVerifier.

The structural catch: free tiers exist to convert signups, and they get abused for exactly that reason, someone burns the free batch scrubbing a scraped list and never becomes a paying customer. Vendors respond by capping free tiers tightly (dozens to a few hundred checks) and by putting the least engineering investment into their hardest cases. Catch-all domains, roughly 30-40% of B2B addresses, are the clearest example: they accept any address at SMTP regardless of validity, so resolving them honestly takes more than a free tier's syntax-and-MX pass. A free result that confidently marks a catch-all address "valid" is often a guess dressed as a status field.

Free by design instead

InboxPolicy doesn't have a free tier, but it isn't free-of-nothing either. Three things cost 0 credits on every plan, permanently, not as a limited-time offer:

• 72-hour re-verification cache: check the same address again within 72 hours and it returns from_cache at 0 credits. Eligible matching cache hits are 0 credits by default, not something you have to ask for.
• Malformed-email rejection: addresses that fail syntax checks never reach SMTP and are never billed.
• The $0.01 x402 keyless call: no signup, no card, no account. A request with no credentials returns HTTP 402 with payment terms; pay one cent in USDC on Base and the same call returns the send-decision with normalized signals.

That's the honest framing: InboxPolicy isn't free, but the floor for trying a real SMTP-backed verification, not a syntax guess, is one cent, with no account required to find that out. For the mechanics of the pay-per-call flow, see x402 email verification; for how the economics compare to credit packs and subscriptions at real volume, see Email Verification API Pricing and the pricing page. For a workflow-based comparison across 8 verification APIs including the free-tier vendors above, see Best Email Verification API (2026).

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