SPF, DKIM, and DMARC solve authentication, proving a message is really from who it claims to be. They don't tell a team whether its emails are actually reaching the inbox rather than spam, which is a separate, ongoing measurement problem that dedicated deliverability tools like Mailmodo, GlockApps, and Folderly are built to solve.
Mailmodo
- Positioning. Built primarily around interactive, AMP-powered emails, with inbox placement testing included as a feature of the broader sending platform rather than a standalone diagnostic tool.
- Best fit. Teams that want to combine interactive email design (in-email forms, surveys, carts) with placement visibility in one platform, rather than running a separate deliverability tool alongside their existing ESP.
GlockApps
- Positioning. A dedicated inbox placement and spam-testing tool, sending seed emails across major mailbox providers to report exactly where a message actually lands, plus content and authentication checks before a send.
- Best fit. Teams that want a standalone diagnostic layer on top of whatever ESP or cold email tool they already use, without switching platforms.
Folderly
- Positioning. Combines placement testing with ongoing domain and IP reputation monitoring, plus automated warmup, aimed at teams actively trying to recover or protect sender reputation over time, not just check placement once.
- Best fit. Teams recovering from a deliverability problem, or running high enough cold outbound volume that reputation needs continuous, not one-off, monitoring.
Choosing based on the actual problem
| Situation | Better Fit |
|---|---|
| Want interactive emails plus basic placement visibility | Mailmodo |
| Want a standalone placement and content check alongside an existing ESP | GlockApps |
| Recovering from a reputation problem or running high-volume cold outbound | Folderly |
The underlying test to apply is the same regardless of tool, does it show actual inbox placement by mailbox provider, not just an aggregate spam score, and does it catch problems before a full send rather than only reporting after the damage to reputation is done. A tool that only offers a single spam score without provider-level placement data is measuring the wrong thing for a team trying to actually fix deliverability.
FAQ
Is SPF, DKIM, and DMARC setup enough for good deliverability?
Authentication is necessary but not sufficient. It removes the most common reason mail gets rejected outright, but inbox placement also depends on sender reputation, engagement rates, list hygiene, and content patterns that authentication alone doesn't fix. A properly authenticated domain can still land in spam if reputation or engagement is poor.
- Authentication prevents outright rejection but doesn't guarantee inbox placement.
- Reputation, engagement, and list hygiene matter just as much once authentication is correct.
Do I need a dedicated deliverability tool if I'm already using an ESP?
Most email service providers report basic metrics like open and bounce rate, but few give visibility into actual inbox placement by mailbox provider, or flag content and reputation issues before a send goes out. A dedicated deliverability tool fills that gap, and becomes worth the cost once a domain has real sending volume and any history of inconsistent placement.
- ESPs report basic metrics but rarely show real inbox-placement visibility.
- Worth adding once volume is real and placement has been inconsistent.