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Deliverability & Testing Tools

Email delivery, warm-up, and testing tools that help messages reach the inbox.

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List cleaning & verification​

  • Bulk Email Verifier - Clean a list before sending: syntax, MX lookup, disposable/role/typo flags and a 0-100 score, DNS only (no SMTP pings). $0.70 per 1,000 emails.
  • Email Verifier & Validator - Bulk list check: syntax, DNS/MX, disposable, role and free-provider flags; no SMTP probing. Pay per event on Apify: $0.0008 per email ($0.80 per 1,000).
  • Email List Cleaner - Bulk list cleaning before a send: syntax, MX, disposable, role and free-provider checks with typo suggestions; no SMTP probing. Pay per use ($0.50 per 1,000 addresses).
  • MailVeri - Bulk and real-time email verification API and MCP server: SMTP, catch-all, disposable and role detection; pay-as-you-go credits that never expire, 1,000 free.
  • SimpleVerifier - Email list verification with a live SMTP mailbox check: each address comes back valid, risky or invalid with a reason, and catch-all or unconfirmed mailboxes stay risky. Free checks to start, then monthly plans; API and MCP server on paid plans.
  • Email Validation - Validate email addresses in bulk or via API/MCP, pay-as-you-go from $35/10k credits, up to 500 free credits.
  • APIVerve - Email validation and sender-authentication APIs: address validation (format, MX, disposable, role and free-provider flags), a disposable email checker, MX lookup, and SPF, DKIM, DMARC and BIMI record validators. Free plan of 200 credits a month, no card required.
  • CheckMail1 - Email verification API for bulk list cleaning, with disposable, role-based and catch-all detection. REST API and CSV upload; 100 free credits, pay-as-you-go from $5 per 1,000 checks.

Auth, DNS & monitoring​

  • Canny Pigeons - DMARC monitoring that walks you to p=reject: DNS drift alerts, IP threat intel, and free first domain with hosted DMARC.
  • Email Forgery Check - Free, no-signup check of whether anyone can send mail as your domain: reads SPF, DMARC, common DKIM selectors and MX from public DNS in your browser and explains each gap in plain words. MIT, open source. (source)
  • Inboxproof - Free, no-signup email deliverability audit: SPF, DKIM, DMARC, TLS and IP reputation in ~30s, with a spam-risk score.
  • oneclick-check - Free, offline check of one sent message's raw headers for RFC 8058 one-click unsubscribe (Gmail/Yahoo bulk sender rule): https List-Unsubscribe, List-Unsubscribe-Post, and DKIM h= coverage. Stdlib Python, MIT.
  • Pharos Email free tools - Free, no-signup SPF lookup counter (limit of 10), DMARC checker, one-pass domain health check (SPF, DKIM, DMARC, BIMI, MX, reverse DNS) and an SMTP bounce code reference.
  • SolidPing - Uptime monitoring with DNSBL blocklist checks (Spamhaus, SpamCop and others), SMTP, IMAP and POP3 checks, and a passive inbox check that alerts when a periodic email stops arriving. Open source (AGPL-3.0), self-hosted or hosted with a free tier.

Testing, warmup & delivery​

  • Email Campaign Preflight - Offline HTML campaign QA with machine-readable JSON and client-readable Markdown reports.
  • Email Subject Line Tester - Analyzes subject-line length, spam triggers, capitalization, punctuation, and mobile and desktop inbox previews.
  • Emailens - Lints HTML email against 21 clients (Outlook Classic, Gmail, Apple Mail and more) with per-client CSS support, dark mode simulation and copy-paste fixes. Free tier, plus a CLI, GitHub Action and MCP server.
  • Mailtrap - is a testing tool and is not designed to deliver emails to real addresses
  • Mailwarm - Don't land in spam anymore
  • Sendgrid - Email delivery service
  • Sparkpost - is the world’s first and only predictive email intelligence platform
  • Warmerly - Email warmup for Google, Microsoft and SMTP mailboxes plus cold email campaigns, with SPF/DKIM/DMARC monitoring, blocklist checks and inbox placement tests. Free plan.