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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SpamRate
SpamRate is an email deliverability testing platform for teams that send newsletters, transactional messages, and marketing campaigns. Users send a test message to a set of seed mailboxes at Gmail, Outlook, Yahoo, and Zoho, and SpamRate reports where each copy was placed, separating the inbox from spam and from tabs such as Promotions. Every test also runs technical checks on the sending domain, covering SPF, DKIM, DMARC, MX, PTR, BIMI, MTA-STS, and DANE records, together with domain and IP blacklist lookups and an analysis of message content and authentication headers. The results are combined into a spam rate score alongside the specific issues that lowered it, and every test is stored so changes over time stay visible. Scheduled monitors repeat the tests and send alerts when placement or authentication changes. A WordPress plugin brings the same checks into the WordPress admin, and a set of DNS and domain diagnostic tools is available without an account.
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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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GoDMARC
Actively block phishing Boost Email Deliverability Get Visibility - DMARC. To secure your inbox and boost email deliverability check your domain status below. What is DMARC? DMARC is an email authentication protocol designed to offer email domain owners the ability to safeguard their dedicated domain from unauthorized usage. DMARC at a Glance Professional DMARC Services. The most commonly used technical term DMARC is the abbreviation for Domain-based Message Authentication Reporting & Conformance. It is a modus operandi that makes the use of Sender Policy Framework (SPF) and Domain Keys Identified Mail (DKIM) in order to identify the legitimacy of a message in the form of an email. Both SPF and DKIM play an important role and DMARC requires them for the specific purpose. It aims to improve and monitor domain protection from the varied fraudulent emails send by fraud minds active in the different corners of the world. With DMARC you can instruct receiving servers
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