Mailook

Mailook positions itself as a straightforward, free email deliverability checker aimed at anyone who sends emails and wants to avoid the spam folder. Unlike many paid tools that bundle deliverability checks into broader marketing suites, Mailook focuses on a single, essential function: telling you exactly why your emails aren't landing in the inbox and how to fix it. With over 60,000 reports generated, it has already built a solid user base among small businesses, outbound agencies, and individual senders.

The tool runs a comprehensive audit based on more than 120 checkpoints. It checks whether your domain and IP are listed on over 100 blacklists, validates your SPF, DKIM, and DMARC DNS records, and provides a deliverability score. The upcoming inbox spam check feature will test how major email providers like Gmail, Outlook, and Yahoo treat your messages. Each issue comes with actionable tips and tutorials, so you don't need to be a deliverability expert to fix problems.

Mailook is completely free, with no hidden tiers or credit limits. You can run unlimited checks and generate public report links to share with clients or teammates. The dashboard keeps a history of all your reports, making it easy to track improvements over time. The tool also offers exclusive discounts on partner deliverability services like email warm-up and list verification, adding extra value for users who want to go further.

User feedback is consistently positive. An outbound agency director reported raising their delivery rate from 74% to 98% after following Mailook's recommendations. Marketing managers and sales leads describe it as "the best tool around" and "fantastic... and free." The main limitation is that it doesn't include advanced features like automated monitoring, A/B testing of email content, or integration with email sending platforms. For power users running large-scale campaigns, Mailook works best as a diagnostic starting point rather than a full-time monitoring solution.

Mailook is ideal for small business owners, solo founders, and lean sales teams who need a no-cost way to diagnose deliverability problems. It's also useful for agencies that want to quickly audit client domains before launching campaigns. If you're already using a paid deliverability platform, Mailook can serve as a second opinion or a lightweight alternative for basic checks. For those just starting with cold email or struggling with spam placement, it's one of the most accessible tools available.

In a market crowded with expensive deliverability suites, Mailook stands out by being genuinely free and genuinely useful. It doesn't try to be everything to everyone -- it does one thing well and does it without a paywall. If your goal is to understand why your emails are going to spam and get clear, actionable steps to fix it, Mailook is a smart first stop.