Email on Acid by Sinch vs GlockApps
Side-by-side from the Top 11 ranking of The 11 Best Email Deliverability Tools (2026). Last verified June 15, 2026.
The short answer
GlockApps ranks higher on Top 11 (#1 vs #6) for Email marketers and developers improving inbox placement rates. Top-tier inbox placement testing with a broad, international seed list and actionable reports.
At a glance
| Email on Acid by Sinch | GlockApps | |
|---|---|---|
| Top 11 rank | #6 / The 11 Best Email Deliverability Tools (2026) | #1 / The 11 Best Email Deliverability Tools (2026) |
| Score (out of 9.4) | 8.1 | 9.2 |
| Best for | Pre-send testing workflow | Detailed inbox placement testing |
| Pricing | $$ ($99 to $599/mo) | $$ ($79 to $399/mo) |
| HQ | Denver, USA | Hong Kong |
| Founded | 2009 | 2011 |
Email on Acid by Sinch
Combines elite email rendering previews with capable deliverability and blocklist monitoring.
www.emailonacid.com/See full entry in The 11 Best Email Deliverability Tools (2026)
GlockApps
Top-tier inbox placement testing with a broad, international seed list and actionable reports.
glockapps.com/See full entry in The 11 Best Email Deliverability Tools (2026)
Methodology and scoring weights live at /methodology. No vendor pays for placement — see about.