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Best email deliverability tools compared
Deliverability tools answer different questions: is my setup right, where do my messages land, and how do mailbox providers see my reputation?
Disclosure: we have no affiliate or commercial relationship with any vendor below at the time of writing. If that changes, links will be marked. Prices and plans change often, so confirm on each vendor's site.
Three kinds of tool
- Configuration checks: DNS and authentication records. Free tools, including ours.
- Placement and content tests: send to seed addresses and report inbox vs spam.
- Reputation data: what Gmail and Microsoft themselves report about your domain and IPs.
The options
| Tool | Type | Cost | What it does |
|---|---|---|---|
| Google Postmaster Tools | Reputation | Free | Gmail spam rate, authentication and compliance status for your domain; required viewing for bulk senders |
| Microsoft SNDS | Reputation | Free | Data on IPs you control sending to Outlook.com |
| GlockApps | Placement tests | Paid, limited free tests | Seed-list inbox placement across providers, spam filter tests, DMARC analytics |
| Mail-tester | Content test | Free for a few tests a day | Send one message, get a score covering authentication, content and blocklists |
| Validity Everest | Enterprise suite | Paid | Inbox placement, reputation, sender certification and list validation |
| MxToolbox | DNS and blocklists | Free lookups, paid monitoring | Widely used blocklist and DNS lookups with alerting plans |
| Mailtrap | Testing and sending | Free tier | Email sandbox for development plus a sending API |
A practical stack
- Fix configuration first: run the domain health check.
- Register in Google Postmaster Tools (and SNDS if you run your own IPs).
- Use a placement test before big campaigns or after infrastructure changes.
- Monitor records daily so a DNS edit doesn't silently undo the work.
Frequently asked questions
What is the single most useful free deliverability tool?
For mail to Gmail, Google Postmaster Tools, because it shows Google's own view of your spam rate and reputation.
Are seed-list placement tests accurate?
They are a useful signal but not exact: real inbox placement also depends on each recipient's engagement history.
Related tools
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