“Spam score: 6/10” is what most tools give you. It's an averaged number that doesn't map to reality, because providers weight triggers differently. A draft that hits Gmail Primary cleanly may trip SmartScreen; one that sails through Outlook might land in Mail.ru Spam.
For each of Gmail, Outlook (M365 + consumer), Yahoo, Mail.ru, Yandex, ProtonMail, Rambler, and the workspace variants of Gmail and Microsoft, we compute a separate score driven by that provider's known filter behaviour. You get a matrix: provider × score × specific reasons.
Why providers differ
- Gmail weights engagement diversity and content freshness heavily; discounts synthetic engagement.
- Microsoft SmartScreen runs stronger on content pattern-matching and URL reputation.
- Yandex is ML-heavy on domain reputation and latency patterns.
- Mail.ru enforces strict DKIM alignment and FBL participation; content triggers secondary.
- ProtonMail has low visibility but strong content scoring and TLS preference.
What you see in the report
- Per-provider score 0–100.
- Per-provider top 3 reasons for the score.
- Per-provider recommended fixes (ranked by impact on that provider).
- Global fixes that help across providers.
Example
A draft with three links scores 82 on Gmail but 54 on Outlook — because SmartScreen weights link count harder. Fix one link and you lift Outlook to 76 without meaningfully affecting Gmail. The matrix lets you make that trade consciously.
Paste a draft and see the matrix. Free, no signup.