Free checkers
Free Email Deliverability Checkers
Every shipped checker on a single index — 11 free tools grouped by the four producer-side topics: Authentication, Deliverability, Reputation, and Warm-Up. Pick the group you want, open a checker, paste a domain or message, and get a 0–100 score plus a per-protocol breakdown in under 30 seconds. No signup required.
The audit combines the available free checks into one complete sender reputation review, so you can see the whole picture before choosing an individual fix.
Authentication
Authentication checkers
SPF, DKIM, and DMARC — the three DNS-based protocols that prove a message came from the servers it claims to and feed the per-provider reputation scores.
0–100 RFC 7208 verdict plus per-mechanism pass/warn/fail breakdown — qualifier posture, DNS-lookup budget against the §4.6.4 cap of 10, and inline copy-pasteable `-all` replacement hints.
Open checker →0–100 DKIM score plus 3–5 findings on RFC 6376 tag parsing — key length, hash choice, canonicalization, and replay scope — for any selector you pick.
Open checker →0–100 RFC 7489 verdict plus per-axis pass / warn / fail breakdown for v=, p=, sp=, pct=, rua=, ruf=, adkim=, aspf= at _dmarc.<domain> — with inline remediation tips.
Open checker →Deliverability
Deliverability checkers
The per-domain score, suite-level signals, and content signals — three lenses on how the inbox placement cycle actually works.
Rate ten deliverability signals from 0–10, apply the 30/30/20/20 category weights, and get a local 0–100 composite plus the two areas to revisit first.
Open checker →Resolve MX hosts and numeric priorities, identify recognized providers versus unknown/self-hosted servers, and get a 0–100 posture score plus plain-English fallback findings.
Open checker →AI-scored 0–100 verdict for any sending domain — per-sub-component breakdown and the top 3–5 risk factors driving the composite.
Open checker →Paste a raw header block from your inbox — get a spam-likelihood rating plus SPF / DKIM / DMARC verdicts against the same RFCs the providers check.
Open checker →0–100 trigger-phrase score plus the exact phrases that drove it — excessive caps, urgency language, link density, and spammy punctuation in a single paste-and-score pass.
Open checker →Reputation
Reputation checkers
Per-list severity and blocklist lookups — the surface a sender runs when inbox placement drops and a Spamhaus / Barracuda / SenderScore hit is suspected.
Start with the free blacklist checker for a domain or sending IP when you need a focused sender reputation check alongside the broader reputation risk view. The separate blacklist lookup checker below provides direct per-list domain status.
0–100 blocklist risk score for any domain / IP, with the per-list severity profile a fresh sender needs to read before the next send.
Open checker →Domain-only lookup across the configured DNSBLs — see a clean/listed verdict, affected blocklist names, and the complete clean/listed/unavailable matrix in one pass.
Check domain blocklist status →Warm-Up
Warm-Up checkers
The ramp plan — the single most consequential variable for deliverability on a brand-new domain and the schedule that lifts a re-activated sender back to safe volume.
0–100 warm-up health score for any sending domain — paste a domain, get an AI narrative on SPF / DKIM / DMARC / MX posture plus 3–5 findings for a safer ramp volume.
Open checker →Start with the SPF / DKIM / DMARC check
The fastest way anywhere on this page is to paste a sending domain into the free authentication checker — get a 0–100 score plus per-protocol pass/warn/fail verdicts in under 30 seconds, with no signup required.