# Postelist

> Real-time email verification with native SMTP probes across an IPv6 pool, provider-aware oracles for Microsoft 365 federated tenants, iCloud, Yahoo, QQ, NetEase, and Proton, and per-mailbox catch-all resolution. Pay-as-you-go from $1 per 1,000 emails, no monthly subscription, 50,000 verifications per minute throughput.

Postelist is operated by an independent team and runs on dedicated infrastructure. The product is a hosted email-verification API plus a dashboard for uploading lists, viewing per-address verdicts, and piping verdicts into ESPs (SendGrid, Klaviyo, Mailchimp, ActiveCampaign, Customer.io, HubSpot, Zapier, Webhook).

Use cases: cleaning subscriber lists before a send, real-time signup form validation, suppressing bounces in marketing automation, deliverability hygiene for cold-outbound, and qualifying leads against business mailboxes.

## Product

- [Postelist homepage](https://postelist.com/): Product overview, pricing slider, accuracy and speed claims, native provider coverage.
- [API documentation](https://postelist.com/docs/api): REST API reference for single-address verification, bulk job upload, and webhook delivery.
- [Sign up free](https://postelist.com/signup): 100 free verifications on signup, no card required.
- [Sign in](https://postelist.com/login): Existing customer sign-in.

## Competitor comparisons

- [Postelist vs EmailListVerify](https://postelist.com/vs/emaillistverify): Side-by-side feature, pricing, and accuracy comparison versus EmailListVerify. $1 vs $30 per 10,000, 99.99% vs ~97% accuracy, native QQ/NetEase oracles, real-time SMTP on every check.

## Journal — deliverability articles

- [How to clean your email list](https://postelist.com/journal/clean-email-list): A working playbook for scrubbing subscriber lists: what cleaning actually means, why it matters for deliverability, the practical steps, and how to re-engage the quiet ones.
- [Why your emails land in spam](https://postelist.com/journal/why-emails-go-to-spam): The signals mailbox providers actually weigh when they decide between your inbox and the spam folder, and the order in which to check them.
- [What SPF, DKIM, and DMARC actually do](https://postelist.com/journal/spf-dkim-dmarc): A plain-English explanation of what each authentication record proves, and the only safe order in which to roll them out.
- [How to warm up a new sending domain](https://postelist.com/journal/warm-up-sending-domain): Why warmup exists, a two-week schedule that works in practice, the three numbers to watch, and when a domain is warm enough to scale.
- [What a catch-all domain actually is](https://postelist.com/journal/catch-all-domains): What a catch-all domain is in SMTP terms, why legitimate companies run them, why verification cannot always confirm deliverability, and how to handle catch-all addresses on your list.
- [All articles](https://postelist.com/journal): Index of every Postelist deliverability article.

## Legal

- [Privacy Policy](https://postelist.com/privacy): How Postelist handles customer data and verification addresses.
- [Terms of Service](https://postelist.com/terms): Terms governing use of the Postelist service.
- [Data Processing Agreement](https://postelist.com/dpa): GDPR-aligned DPA covering processing of personal data on behalf of customers.

## Optional

- [Sitemap](https://postelist.com/sitemap.xml): Machine-readable URL index of the marketing site.
- [Robots](https://postelist.com/robots.txt): Crawler directives.