Domain Reputation Checker

What is domain reputation?

Domain reputation is the trust score a mailbox provider — Gmail, Outlook, Yahoo — assigns to your sending domain, separate from the IP address you send through. It's built from your history of spam complaints, authentication results, blocklist status, and how recipients actually engage with your mail: opens, replies, deletes-without-reading, and "not spam" rescues from the junk folder.

Domain-level reputation matters more than it used to because IP reputation gets diluted the moment you send through a shared ESP IP pool — thousands of other senders' behavior blends into the same score. Your domain is yours alone, so its reputation reflects only your sending behavior, and it now travels with you across whatever infrastructure you use to send.

How is domain reputation calculated?

• Spam-complaint rate — the single heaviest signal. Google's current sender guidelines put the danger line at 0.3% of messages marked spam; staying under 0.1% is the safe target.
• Authentication alignment — SPF, DKIM, and DMARC all need to pass, and DMARC needs the SPF/DKIM domain to align with your visible From: domain. Presence alone isn't enough; alignment is what receivers actually check.
• Public blocklist presence — receiving mail servers check domain and IP blocklists in real time before accepting a connection. A single listing on a widely-used list (Spamhaus, Barracuda) can silently drop your delivery rate.
• Sending consistency — a sudden volume spike from a previously quiet domain reads as a compromised account or a spam run, even if it's a legitimate campaign launch.
• Engagement — opens, replies, and manual "not spam" moves build reputation; deletes-without-opening and spam-folder placement erode it.
• Bounce rate — a high hard-bounce rate signals poor list hygiene, which mailbox providers read as a spam-adjacent sending pattern.
• Domain age and history — a brand-new domain starts with no reputation at all, not a bad one — but it needs gradual volume warm-up rather than an immediate full-send.

How to check your domain reputation (4 free ways)

No single free tool gives the complete picture — each one checks a different layer. Here's what each actually shows in 2026.

1. Google Postmaster Tools

Free, but requires verifying your domain via a DNS TXT record and enough Gmail-bound sending volume to generate data. Important 2026 change: Google retired the old four-tier High/Medium/Low/Bad domain and IP reputation dashboards in Postmaster Tools v2. In their place, a Compliance Status dashboard shows a simple Pass or Needs Work against your SPF, DKIM, DMARC, and spam-rate thresholds — if you're reading a guide that still describes the old scoring tiers, it's out of date.

2. Cisco Talos Intelligence domain reputation

A free lookup at talosintelligence.com/reputation_center — enter your domain and get a threat-level classification (trusted, neutral, or untrusted) built from Cisco's web, email, and network telemetry, refreshed roughly every three hours. Most domains land as "neutral" by default; Talos explicitly does not recommend blocking neutral domains, so a neutral result isn't a red flag on its own. Domain owners can dispute an incorrect rating directly through Talos's ticket system.

3. MXToolbox blacklist and health check

Free for one monitored IP across roughly 30 public blocklists, plus a full suite of one-off DNS/MX lookup tools. Continuous multi-IP monitoring, DMARC management, and inbox-placement testing sit behind MXToolbox's paid Delivery Center plans, which are custom-quoted rather than published at a flat rate.

4. SpamAssassin spam score check

Unlike the tools above, SpamAssassin isn't a public online lookup — it's an open-source filter you (or your host) run on your own mail server, and you check your score by sending yourself a test message. The default spam threshold (required_score) is 5.0, which Apache's own documentation calls "quite aggressive" for a single mailbox — many ISP-scale deployments raise it to 8.0-10.0. Since you can't control the receiving server's threshold, aim for a raw outbound score of 0-2 to stay safely under every provider's cutoff.

Checking public blocklists directly

Beyond MXToolbox's aggregated check, the major blocklists worth checking individually are Spamhaus (DBL for domains, ZEN for IPs), Barracuda Reputation Block List, SORBS, and SpamCop. Each publishes its own free lookup and delisting process — a listing on any one of them is worth investigating even if your Postmaster Tools compliance status shows Pass, since blocklists and mailbox-provider compliance dashboards don't always agree.

Free tools vs. one nqzai audit

The free tools above each answer one question. nqzai's domain send-readiness audit answers all of them in a single pass, and — the one thing none of the free tools do — pushes the DNS fix directly to your Cloudflare zone when something's broken.

Pricing shown is nqzai's pay-as-you-go token rate ($2 per million tokens, 1 million tokens free on signup — no subscription or platform fee). MXToolbox's paid tier requires contacting sales for a quote; exact pricing wasn't published at time of writing.

What a healthy domain reputation looks like

• Spam-complaint rate under 0.1%, never above 0.3%
• SpamAssassin raw score of 0-2 on outbound test messages
• SPF, DKIM, and DMARC all passing and aligned — not just present in DNS
• Zero hits across Spamhaus, Barracuda, SORBS, and SpamCop
• A Postmaster Tools Compliance Status of Pass on every dimension it checks

A failing domain is exactly the kind of execution constraint an AI marketing plan surfaces up front — no outbound initiative gets scheduled ahead of a blocker that would sink its deliverability before it's measured.

Reports tell you what happened. Ask nqzai why.

A DNS checker tells you which records are missing. It cannot tell you whether that is why your email is not landing — and if you fix the wrong thing, you spend two weeks confirming it did not help. nqzai reads the records and your actual sending outcomes together.

The report is still produced and saved — it rides along as the evidence for the answer, instead of being handed over in place of one. You can open it, copy it, or push it to your CMS. You just don’t have to read it to find out what changed.

Frequently asked questions