InboxPolicy Pricing
By Aria Pramesi, founder of InboxPolicy · Updated July 4, 2026
InboxPolicy’s standard quote is $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. Eligible cache hits and malformed-email rejections can cost 0 credits; API-key replay is limited to the idempotency TTL, and x402 has no replay wrapper.
How much does InboxPolicy cost per verification?
InboxPolicy has two ways to pay. Pay-per-call through x402 has a $0.01 standard quote per fresh verification, with wallet-bound rolling-usage discounts of 20% after 1,000 settled units in 30 days and 40% after 10,000, 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).
Buy a credit pack
Card checkout via Stripe — your API key arrives by email within a minute. Credits never expire.
Starter
- Full API + MCP access
- Free 72h re-verification
- Per-item batch results
- Credits never expire
Builder
- Everything in Starter
- Async batches to 50k emails
- Signed completion webhooks
- Automatic fallback on unknowns
Growth
- Everything in Builder
- Priority rate limits
- Volume pricing on request
- Direct support channel
Prefer no account at all? Agents can pay $0.01 per decision in USDC on Base via x402 — the API answers 402 Payment Required and settles per call. See the docs.
What's always free, no matter which plan?
Two result types can cost 0 credits:
- Cache re-verification within 72 hours. If the same normalized address and strictness were checked in the last 72 hours, and
force_refreshis false, the API can returnfrom_cacheinstantly at 0 credits. - Malformed-email rejection. Addresses that fail syntax checks are rejected before any SMTP check runs, at 0 credits.
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?
By purchase scenario, MillionVerifier's 10,000-credit entry costs $39 ($3.90/1k), versus InboxPolicy Starter at $5 for 1,000 ($5.00/1k), Builder at $19 for 5,000 ($3.80/1k), and Growth at $79 for 25,000 ($3.16/1k). MillionVerifier's 1M tier is lower at $0.45/1k; ZeroBounce starts around $9.90/1k on subscription (min 10,000) or $19.50/1k pay-as-you-go, and Kickbox is around $10.00/1k. 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. To project what your own list costs across x402, packs, and competitors, use the cost calculator.
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. MillionVerifier runs from $3.90/1k at entry down to $0.45/1k at 1M volume, undercutting InboxPolicy at high volume; InboxPolicy's 25,000-credit Growth pack has a lower unit price, while MillionVerifier's 10,000-credit entry purchase costs less overall.
- 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, normalized signals | Yes, MCP server plus x402 pay-per-call | None, first call is $0.01 | Unknown results map to review; catch-all results map to review by default or send_with_caution under aggressive strictness, never guessed as safe |
| ZeroBounce | ~$9.90/1k sub | 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 | $3.90–0.45/1k | Status fields | No | Yes | Resolves unknowns aggressively; lowest cost at high volume for one-shot bulk cleaning |
| Emailable | ~$6.46/1k sub | Status fields | No | Not independently verified | Dashboard-first marketing suite |
Frequently asked questions
How much does InboxPolicy cost per email verification?
The standard x402 quote is $0.01 per fresh verification, paid in USDC on Base; wallet-bound rolling usage discounts it 20% after 1,000 settled units in 30 days and 40% after 10,000. 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?
Two result types can cost 0 credits: an eligible cache hit for the same normalized address and strictness within 72 hours when force_refresh is false, and malformed-email rejection before SMTP. For API-key calls only, the API replays the same route, key, and payload within the idempotency record TTL (24 hours by default). Keyless x402 has no idempotency replay wrapper.
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 starting around $9.90/1k on subscription (min 10,000) or $19.50/1k pay-as-you-go. MillionVerifier runs $3.90/1k at entry down to $0.45/1k at 1M volume; InboxPolicy Growth is $79 for 25,000 ($3.16/1k), while MillionVerifier's entry is $39 for 10,000 ($3.90/1k), a lower total purchase; MillionVerifier also wins on unit price at 1M ($0.45/1k) for one-shot bulk cleaning of large lists. InboxPolicy trades some of that bulk-cleaning cost advantage for a send-decision action plus normalized signals 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 runs $3.90/1k at entry down to $0.45/1k at 1M volume; InboxPolicy Growth is $79 for 25,000 ($3.16/1k), while MillionVerifier's entry is $39 for 10,000 ($3.90/1k), a lower total purchase; MillionVerifier also wins on unit price at 1M ($0.45/1k). 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.