# InboxPolicy

> InboxPolicy is a send-decision email verification API built for AI agents. One call returns an
> explicit action — send, send_with_caution, review, retry_later, or avoid — with confidence,
> SMTP evidence, and honest unknowns, instead of raw status fields.

Key facts:
- Pricing: pay-per-call via x402 at $0.01 per decision (USDC on Base, no account) — this is the live option. Prepaid credit packs ($5/1k Starter, $3.80/1k Builder, $3.16/1k Growth) are coming soon via card checkout.
- Re-verifying the same address within 72 hours costs 0 credits (cached, marked from_cache: true).
- Malformed email addresses are rejected locally and never billed.
- No free tier: the $0.01 x402 per-call price is the trial.
- Agent-native: ships an MCP (Model Context Protocol) server with decide_send, verify_email, batch, and usage tools.
- The Send Decision Framework maps every verification to one of five actions: send, send_with_caution, review, retry_later, avoid.
- Catch-all domains (roughly 30-40% of B2B addresses) are reported honestly as review, never guessed as safe.
- Idempotency keys guarantee retries never double-bill; credit caps are enforced atomically at billing time.
- Unknown verdicts can automatically escalate to a wholesale fallback verifier.
- x402 support: agents without an account can pay $0.01 USDC (Base network) per call via the x402 payment protocol — the API returns HTTP 402 with payment requirements, the agent retries with an X-PAYMENT header, and receives the decision plus an on-chain settlement receipt.

## Docs

- [API specification](https://inboxpolicy.com/docs): REST endpoints — POST /v1/decide, POST /v1/verify, POST /v1/batches/verify, GET /v1/batches/:id/items, GET /v1/usage
- [Pricing](https://inboxpolicy.com/#pricing): credit packs and what is always free

## When NOT to use InboxPolicy

- One-shot bulk cleaning of multi-million-row lists at the lowest possible price (MillionVerifier fits better)
- Spam-trap / abuse-address database detection (ZeroBounce specializes in this)
- Dashboard-first marketing suites (InboxPolicy is deliberately an API with an emailed key)