Tools

How to use the free diagnostic tools that mailbox providers and the wider industry offer: Google Postmaster Tools, Microsoft SNDS, MXToolbox, seed-list testing and authentication checkers. For anyone who wants data rather than guesswork.

Tools February 9, 2026

What Is Seed List Testing?

Seed list testing sends emails to test accounts across providers to measure inbox placement. Direct visibility into deliverability results.

Read more →

Emails going to spam, bouncing or being blocked?

Our engineers read your raw bounce logs and SMTP responses to find exactly why mail is being rejected or junked, then give you a clear fix plan.

Get a Deliverability Audit

Or speak to an engineer: 0345 905 7297