InboxPolicy vs MillionVerifier

By Aria Pramesi, founder of InboxPolicy · Updated July 4, 2026

MillionVerifier wins on price, $0.59-2.50/1k, and is built for one-shot cleaning of large scraped lists, with a free tier and aggressive unknown-resolution. InboxPolicy costs $0.01 per fresh check but returns a send/hold/avoid decision with SMTP evidence for live agent workflows, keeping unknowns honest instead of guessing them safe.

What does each tool return: status fields or decisions?

MillionVerifier returns a status field per email, such as valid, invalid, catch-all, or unknown, built for bulk list cleaning.

InboxPolicy checks syntax, MX, and live SMTP against its own verification engine, then a deliverability policy turns that evidence into one of five actions: send, send_with_caution, review, retry_later, or avoid, along with a confidence score and the SMTP evidence behind the call.

When does MillionVerifier win?

MillionVerifier is the budget king for one-shot cleaning of a large scraped list. At roughly $0.59-2.50 per 1,000 verifications, with a free tier and aggressive resolution of unknowns, it is built to prune a static CSV before a send.

• Cheapest per-check price of the two, at every volume tier.
• Free tier available.
• Resolves unknown or catch-all results into a keep or drop verdict rather than leaving them open.

If the job is cleaning 500,000 scraped rows once, MillionVerifier is the better fit.

When does InboxPolicy win?

InboxPolicy is built for agents deciding whether to send a specific email right now, not for bulk cleanup. It ships an MCP server exposing decide_send, verify_email, batch, and usage tools.

The REST API supports idempotency keys, per-item batch results, async batches up to 50,000 emails, and signed completion webhooks. Agents can also pay per call with no account or API key: a keyless request returns HTTP 402 with machine-readable payment requirements, the agent pays $0.01 USDC on Base via an X-PAYMENT header, and gets back a decision plus an on-chain settlement receipt.

How do InboxPolicy and MillionVerifier prices compare?

InboxPolicy charges $0.01 per fresh verification pay-per-call via x402, or through prepaid credit packs: Starter $5 for 1,000 credits ($5.00/1k), Builder $19 for 5,000 ($3.80/1k), Growth $79 for 25,000 ($3.16/1k). Volume pricing is available on request. There is no free tier, deliberately: free tiers attract list-cleaning abuse.

Three things are always free regardless of plan: cache re-verification within 72 hours (returns from_cache, 0 credits), malformed-email rejection before SMTP (0 credits), and idempotent retries on the same key (never billed twice).

MillionVerifier costs roughly $0.59-2.50 per 1,000, which is cheaper than InboxPolicy at every volume tier shown here. InboxPolicy's price is paying for a decision plus evidence and agent access, not just a lower per-row cost.

How does each tool handle unknown and catch-all addresses?

Roughly 30-40% of B2B addresses sit on catch-all domains, where a mail server accepts any address without confirming a real mailbox exists.

MillionVerifier resolves these unknowns aggressively, giving a binary keep or drop verdict, which is useful when a bulk sender just needs a prune decision. InboxPolicy maps unknown or catch-all results to the action review instead of guessing them safe, on the reasoning that a wrong safe guess costs more in a live send-decision than an unresolved row sitting in a spreadsheet.

Frequently asked questions