GlockApps is a paid inbox-placement tool: it sends test campaigns to Gmail, Outlook and Yahoo and shows you whether a real email lands in the inbox, spam or promotions. That's a genuine capability the free checkers don't have. But it's not the only way to test deliverability, and you may not need it yet. Here's how the alternatives compare.
Most "my email is going to spam" problems are caused by the authentication and reputation layer: a missing or broken SPF, DKIM that isn't signing, a DMARC record set to reject by mistake, no TLS, or a sending IP on a blocklist. You can find and fix all of those for free before spending on placement testing.
Inboxproof runs that full free check in about 30 seconds: MX, SPF, DKIM, DMARC, TLS, PTR and IP reputation, with a single spam-risk score and the exact fix for anything failing. No signup. If your domain passes, placement testing is a reasonable next step; if it fails, fix the free stuff first.
| Tool | Inbox placement | Free domain checks | Price |
|---|---|---|---|
| GlockApps | Yes | Limited | Paid (trial) |
| InboxMonster | Yes | Limited | Paid |
| 250ok | Yes | Some | Paid |
| Litmus | No (design focus) | No | Paid (enterprise) |
| Inboxproof | No | Yes, full stack | Free; Pro adds monitoring + API |
| MXToolbox / Sender Score | No | Single-purpose | Free |
The common pattern is to use the free authentication checks first, then placement testing. Skipping straight to a paid placement tool while your SPF or DMARC is broken wastes the test. The email will land in spam for reasons the placement tool can't fix.
Related: best deliverability tools compared · Mail-Tester alternatives · free spam checker · all guides
Run the free checks first. SPF, DKIM, DMARC, TLS and IP reputation in ~30 seconds, no signup.
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