head to head
GlockApps vs Mail-Tester
Ongoing inbox placement and DMARC analytics versus quick single-message preflight tests.
What matters for teams choosing a transactional API
Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.
| Priority | GlockApps | Mail-Tester |
|---|---|---|
| Idempotency keys | No | No |
| Webhooks | No | No |
| Event stream | Yes | No |
| Operating since | Not published | Not published |
| Suppressions API | No | No |
| Best published rate per 1,000 | Tiers not published in comparable form | Tiers not published in comparable form |
| Batch sending | No | No |
| SDKs | None | None |
| Deliverability | Not a sender. Measures inbox placement and DMARC alignment so teams can diagnose deliverability problems before blaming the ESP. | Not a sender. Scores one message at a time and helps identify obvious authentication, blacklist, and SpamAssassin issues. |
For a transactional workload running high-frequency programmatic sends where a missed delivery is a product failure, GlockApps takes every priority that separates them here (event stream), while Mail-Tester matches it on the rest. That ordering reflects this audience. Weigh the same table differently and the answer changes.
Side by side
| Feature | GlockApps | Mail-Tester |
|---|---|---|
| Webhooks | No | No |
| SDKs | None | None |
| Deliverability | Not a sender. Measures inbox placement and DMARC alignment so teams can diagnose deliverability problems before blaming the ESP. | Not a sender. Scores one message at a time and helps identify obvious authentication, blacklist, and SpamAssassin issues. |
| Tagline | Inbox placement testing plus DMARC analytics. | Simple send-to-test-address spam score checks. |
| Free tier | Free plan with 2 Inbox Insight tests once and 10,000 DMARC messages/mo | 3 tests free within the last 24 hours via the web interface |
| Starts at | $59/mo billed annually for Essential | $50 for 500 tests, or larger prepaid test packs |
| Pricing model | tiered | pay-as-you-go |
| API | Yes | Yes |
| SMTP | No | No |
| Templates | none | none |
| React Email | No | No |
| Inbound | No | No |
| Multi-tenant | Yes | No |
| Idempotency | No | No |
| Dedicated IP | No | No |
| DX score | 7/10 | 8/10 |
| Best for | Growth and marketing teams that regularly test inbox placement across Gmail, Outlook, and other mailbox providers. | Developers and marketers who need a quick preflight check for a specific message. |
GlockApps
pros
- ›Combines spam testing with DMARC analytics
- ›Free plan includes enough to run a first diagnostic
- ›Credit packs are available for teams that do not want a subscription
cons
- ›Subscription pricing is higher than simple DMARC monitors
- ›Inbox tests are only a sample, not a guarantee of every recipient inbox
- ›Annual billing is needed for the lowest published monthly price
Mail-Tester
pros
- ›Very fast manual diagnostic
- ›Free tests cover occasional checks
- ›Paid API and iframe options exist for product integrations
- ›Prepaid test packs do not expire
cons
- ›No ongoing monitoring unless integrated manually
- ›One test does not represent every mailbox provider
- ›Interface is intentionally simple rather than polished