Does InboxPolicy Have a Free Plan?
By Aria Pramesi, founder of InboxPolicy · Updated July 4, 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. What's always free: cache hits within 72 hours, malformed-email rejection, and idempotent retries, each billed at 0 credits.
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?
Three things never cost a credit, regardless of plan:
- Cache re-verification within 72 hours: re-checking the same address inside that window returns
from_cacheand bills 0 credits. - Malformed-email rejection: addresses that fail syntax checks are rejected before they ever reach SMTP, so they cost 0 credits.
- Idempotent retries: resending a request with the same idempotency key never bills twice.
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 an X-PAYMENT 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 $8.00 per 1,000 credits 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.
| Provider | Free Tier | Entry Price | What You Get |
|---|---|---|---|
| InboxPolicy | None, by design | $0.01 per call (x402, pay-per-call) | Action (send, send_with_caution, review, retry_later, avoid) plus confidence score and SMTP evidence |
| ZeroBounce | 100 verifications/month | ~$8.00 per 1,000 | Status fields, spam-trap/abuse database, marketing dashboard |
| Kickbox | One-time free credits | ~$10.00 per 1,000 | Status fields plus a Sendex quality score, dashboard-first |
| MillionVerifier | Yes, has a free tier | ~$0.59 to $2.50 per 1,000 | Status fields, resolves unknowns aggressively |
| Emailable | Not specified here | Not specified here | Dashboard-first suite with bulk uploads and integrations |
Frequently asked questions
Does InboxPolicy have a free trial?
There's no separate free trial product. The $0.01 per-call x402 price is the trial: a keyless request returns an HTTP 402 response with payment requirements, the agent pays $0.01 in USDC on Base, and gets back a send-decision with SMTP evidence. No account or API key is needed to start.
Is anything on InboxPolicy actually free?
Yes, three things always cost 0 credits: cache re-verification within 72 hours (returns from_cache), malformed-email rejection (caught before SMTP), and idempotent retries (a repeated request with the same idempotency key is never billed twice). These apply on every plan, not just a free tier.
Why doesn't InboxPolicy offer a free tier like ZeroBounce's 100/month?
Free tiers attract list-cleaning abuse: someone signs up, burns the free allotment on a scraped list, and never pays. InboxPolicy skips that by charging $0.01 per fresh verification from the first call, with no signup step to abuse in the first place.
What's the cheapest way to use InboxPolicy without paying per call?
Prepaid credit packs lower the per-verification cost as volume increases: Starter is $5 for 1,000 credits ($5.00/1k), Builder is $19 for 5,000 ($3.80/1k), and Growth is $79 for 25,000 ($3.16/1k). Volume pricing is available on request for larger needs.
Should I use a free email verifier instead of InboxPolicy?
If you need to clean a large scraped list once at the lowest possible cost, MillionVerifier's free tier and low bulk pricing fit better. If you need spam-trap and abuse-address detection, ZeroBounce's free tier and dedicated database fit better. InboxPolicy targets agents making live send-decisions, not one-time list cleaning.
Does InboxPolicy require a credit card or account to try it?
No. The x402 pay-per-call flow needs no account and no API key, only a USDC payment on Base sent via an X-PAYMENT header for each $0.01 verification. An account is only needed if you choose a prepaid credit pack instead, which is paid by card with a key emailed to you.