InboxPolicy Pricing
By Aria Pramesi, founder of InboxPolicy · Updated July 4, 2026
InboxPolicy costs $0.01 per fresh email verification, paid per call via the x402 protocol in USDC on Base, no account or API key needed. For prepaid use, credit packs run from $3.16 to $5.00 per 1,000 verifications. Cache hits, malformed-email rejections, and idempotent retries are always free.
How much does InboxPolicy cost per verification?
InboxPolicy has two ways to pay. Pay-per-call through x402 costs $0.01 per fresh verification, settled in USDC on Base with no account, no signup, and no API key. Or prepay by card for a credit pack, which lowers the effective rate as volume goes up.
| Option | Price | Credits | Effective rate per 1,000 | Payment |
|---|---|---|---|---|
| Pay-per-call (x402) | $0.01 / call | 1 at a time | $10.00 | USDC on Base, no account |
| Starter pack | $5 | 1,000 | $5.00 | Card, key emailed |
| Builder pack | $19 | 5,000 | $3.80 | Card, key emailed |
| Growth pack | $79 | 25,000 | $3.16 | Card, key emailed |
Volume pricing is available on request above the Growth pack. Every price is for a fresh verification; cached, malformed, and duplicate-retry calls do not consume credits at all (see below).
What's always free, no matter which plan?
Three cases never bill a credit, on any plan:
- Cache re-verification within 72 hours. If the same address was checked in the last 72 hours, the API returns
from_cacheinstantly at 0 credits. - Malformed-email rejection. Addresses that fail syntax checks are rejected before any SMTP check runs, at 0 credits.
- Idempotent retries. Resending a request with the same idempotency key never bills twice, even if the client retries after a timeout.
These apply to both the x402 pay-per-call path and prepaid credit packs.
Why doesn't InboxPolicy have a free tier?
It doesn't, on purpose. The $0.01 x402 call is the free trial: anyone can verify one email for a cent with no signup, no key, and no commitment, then decide if the output is useful.
Traditional free tiers (100 free verifications a month, one-time free credits, and similar) are a known target for list-cleaning abuse, where the same operation is split across many free accounts to avoid paying for volume. Charging $0.01 from the first call removes that incentive.
How does InboxPolicy pricing compare to competitors?
On raw price per 1,000 verifications, InboxPolicy's prepaid packs ($3.16 to $5.00) sit between MillionVerifier (roughly $0.59 to $2.50) and ZeroBounce (roughly $8.00) or Kickbox (roughly $10.00). The comparison table below lists entry pricing and what each tool returns.
The pay-per-call x402 rate ($0.01 each, or $10.00 per 1,000 if you never buy a pack) is priced for one-off or agent-triggered checks, not bulk cleaning; the credit packs are the better deal for volume.
When is InboxPolicy not the cheapest option?
Three scenarios where a competitor's price or feature set fits better:
- One-shot cleaning of a large scraped list at the lowest cost. MillionVerifier's $0.59 to $2.50 per 1,000 undercuts InboxPolicy's packs for pure bulk cleanup.
- Spam-trap or abuse-address detection. ZeroBounce maintains a dedicated spam-trap and abuse database that InboxPolicy does not offer.
- Dashboard-first workflows with CSV uploads. Kickbox and Emailable are built around a marketing-team dashboard rather than an API or MCP server.
| Provider | Entry price per 1,000 | Output | MCP / agent support | Free tier | Notable |
|---|---|---|---|---|---|
| InboxPolicy | $3.16-$5.00 (packs), $10.00 pay-per-call | Send-decision action, confidence score, SMTP evidence | Yes, MCP server plus x402 pay-per-call | None, first call is $0.01 | Unknown/catch-all results map to review, never guessed as safe |
| ZeroBounce | ~$8.00 | Status fields | No | 100/month | Dedicated spam-trap and abuse-address database, marketing dashboard |
| Kickbox | ~$10.00 | Status field plus Sendex score | No | One-time free credits | Dashboard-first workflow |
| MillionVerifier | ~$0.59-$2.50 | Status fields | No | Yes | Resolves unknowns aggressively, budget choice for one-shot bulk cleaning |
| Emailable | Not published in this comparison | Status fields | No | Not published | Dashboard-first marketing suite |
Frequently asked questions
How much does InboxPolicy cost per email verification?
Each fresh verification costs $0.01, paid per call through the x402 protocol in USDC on Base. No account or API key is required for pay-per-call use. For higher volume, prepaid credit packs bring the effective rate down to $3.16 to $5.00 per 1,000 verifications, paid by card with a key emailed after purchase.
Does InboxPolicy have a free tier?
No. The $0.01 per-call x402 price is the trial itself, so anyone can test with a single verification before committing. This is deliberate: free tiers attract list-cleaning abuse, where users churn through free credits across many accounts rather than paying for verification volume.
What verifications are always free?
Three cases never bill: re-verifying an email already checked within the past 72 hours returns instantly from cache at 0 credits, malformed emails are rejected before any SMTP check at 0 credits, and retrying a request with the same idempotency key never bills twice.
How does InboxPolicy pricing compare to ZeroBounce and MillionVerifier?
InboxPolicy's prepaid packs run $3.16 to $5.00 per 1,000, cheaper than ZeroBounce's roughly $8.00 per 1,000. MillionVerifier is cheaper still at roughly $0.59 to $2.50 per 1,000 for one-shot bulk cleaning of large lists. InboxPolicy trades some of that bulk-cleaning cost advantage for a send-decision action plus SMTP evidence instead of a raw status field.
What do the credit packs include?
Three packs are available, paid by card with a key emailed on purchase: Starter at $5 for 1,000 credits ($5.00 per 1,000), Builder at $19 for 5,000 credits ($3.80 per 1,000), and Growth at $79 for 25,000 credits ($3.16 per 1,000). Volume pricing is available on request for larger needs.
When should I use a cheaper competitor instead of InboxPolicy?
For one-shot cleaning of a large scraped list at the lowest possible cost, MillionVerifier's $0.59 to $2.50 per 1,000 is cheaper. For spam-trap and abuse-address detection, ZeroBounce carries a dedicated database InboxPolicy does not. For a dashboard-first workflow with CSV uploads, Kickbox or Emailable fit better than an API-first tool.