head to head
GlockApps vs Mail-Tester
Ongoing inbox placement and DMARC analytics versus quick single-message preflight tests.
What matters for teams building autonomous agents
An agent stack treats email as a two-way primitive. Inbound has to arrive as structured JSON a tool call can consume, sends have to be safe to retry when a model loop repeats itself, and every action needs an audit trail. A provider without inbound parsing only solves half the problem.
| Priority | GlockApps | Mail-Tester |
|---|---|---|
| Inbound parsing | No | No |
| Idempotency keys | No | No |
| Webhooks | No | No |
| Operating since | Not published | Not published |
| Event stream | Yes | 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 |
| Multi-tenant | Yes | No |
For an agent that reads and writes email running inbound parsing into tool calls and model-generated sends that must not duplicate, GlockApps takes every priority that separates them here (event stream and multi-tenant support), 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 |
| Multi-tenant | Yes | No |
| 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 |
| Idempotency | No | No |
| Dedicated IP | No | No |
| 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. |
| 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