WillItInbox
WillItInbox is an email deliverability and validation platform for SaaS teams, developers, agencies, marketers, and newsletter operators that depend on outbound email.
Teams can generate a unique test inbox, send a real message from their app or ESP, and receive a practical deliverability report across SPF, DKIM, DMARC, BIMI, DNS, reverse DNS, blocklists, TLS, headers, content, links, reputation, and sender infrastructure.
WillItInbox also validates individual emails and bulk CSV lists using syntax, DNS/MX, disposable, role, typo, provider, catch-all, SMTP, suppression, and confidence signals. It includes domain monitoring, DMARC report analysis, sending source visibility, provider reputation checks, API keys, webhooks, scheduled checks, incident diagnostics, inbox placement checks, team workspaces, and exportable reports.
Paid plans start at $39/month. PAYG credits are available for extra email validation and deliverability testing usage.
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InboxStack
InboxStack is an email deliverability intelligence platform built around Brain, a proprietary causal AI engine that identifies why emails miss the inbox — not just that they did. Most deliverability tools stop at monitoring: they show a drop in inbox placement or a blocklist hit and leave you to investigate. InboxStack goes further, correlating signals from your ESP, DNS authentication records (SPF, DKIM, DMARC), Google Postmaster Tools, Microsoft SNDS, and 50+ blocklists through a causal knowledge graph built on a 22-year deliverability knowledge base — tracing the actual root cause, whether it's a DKIM misalignment, IP reputation dip, or content trigger.
Onboarding starts with forwarding your email headers for an instant DNS/auth audit, no migration required. Teams that want ongoing monitoring can connect their ESP and Postmaster accounts, with optional seed testing for real inbox-vs-spam placement data.
Built especially for digital agencies and ESP's.
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GlockApps
Where are your emails delivered?
Receive reports with an in-depth understanding of what your emails are doing and how to increase your reputation and deliverability before you hit Send!
In your reports you can:
❖ Check to see if your sending IPs or Domains are listed within 50+ major email blacklists.
❖ Protect your identity by identifying, monitoring, and rejecting unauthenticated outgoing emails.
❖ Identify whether your email’s content or reputation is being flagged as Spam by all major B2B and B2C email marketing providers.
❖ Fix HTML errors and identify “risky” content before sending.
❖ Get instantly notified when issues occur by email, Slack, or Telegram.
Want to speak with an expert?
Book a 1-hour consulting call to get all your email marketing and deliverability questions answered. We also offer comprehensive Email Deliverability Audits with personalized recommendations for companies looking to maximize their revenue with email.
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ZeroBounce
ZeroBounce is an email verification, scoring and deliverability platform helping businesses improve their inbox placement. The service detects email typos, nonexistent and abusive email accounts, spam traps and other risky email addresses.
ZeroBounce also provides an email scoring service and a suite of deliverability tools to further enhance email inbox placement. The company operates a military-grade security infrastructure, ensuring customer data is protected at the highest levels.
With more than 23 billion emails validated to date, ZeroBounce serves 400,000+ businesses in 190+ countries and adds up to 200 new clients every day. Companies using email lists validated by ZeroBounce report a 99%+ accuracy rate and maintain a good sending reputation. In 2019, ZeroBounce took no. 851 on the Inc. 5000 list of the fastest-growing private companies in the United States. In 2020, ZeroBounce rose to no. 40 on the list. In 2021, ZeroBounce was number 9 on the Inc. 5000 Regionals list.
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