Comparison
DeliverSight vs mail-tester.com
Both give you a score for a message you send in, free and without an account. DeliverSight does not stop there: the same test, plus continuous monitoring of the domain, DMARC report aggregation, alerts when something breaks, and an API — so the fix stays fixed instead of being rechecked by hand.
mail-tester.com details checked 2026-07-29 against their own published pricing. We have not linked to them; the figures are here so you do not have to go looking.
Why teams pick DeliverSight
- The test is the start rather than the whole product: add the domain and its records, certificates and blocklist status are checked on a schedule.
- DMARC aggregate reports are collected and grouped, so you can see who sends as your domain instead of parsing XML.
- Alerts by email, Slack, Teams, Telegram or webhook when something breaks.
- A REST API with webhooks, so a deliverability check can run in CI rather than in a browser tab.
- Saved history on an account, so you can compare a message against the last one.
Side by side
| Capability | DeliverSight | mail-tester.com |
|---|---|---|
| Free test with no account | Yes | Yes |
| Free tests per day | 3 | 3 |
| Score out of 10 | Yes | Yes |
| Authentication checks (SPF, DKIM, DMARC) | Yes | Yes |
| Content and spam-filter analysis | Yes | Yes |
| Blocklist checks | Yes | Yes |
| Scheduled domain monitoring | Yes | No |
| Certificate, MTA-STS and TLS-RPT checks | Yes | No |
| DMARC report aggregation | Yes | No |
| Alerts when something breaks | Yes | No |
| REST API and webhooks | Yes | Paid add-on |
| Saved test history | Yes, on an account | Short-lived |
mail-tester publishes a free tier of 3 tests per 24 hours with no account. We deliberately do not quote its paid rates here: it blocks automated checking and the figures we could find disagreed with each other, so anything we printed might be wrong. Only the free tier is stated here, because it is the figure we could confirm.
Choose DeliverSight if…
The question you actually have is not "is this message okay" but "will my mail keep arriving" — which needs something watching the domain after the test is done.
Check it against your own mail
You do not have to take this on trust. Send one message to a generated address and read the full report — authentication, content, reputation and blocklists, with the reasons behind every deduction. Three a day, no account, no card. Then add the domain and see what monitoring actually reports back.
See our pricing in full, the complete feature list, or the other comparisons.