5 Best Cold Email Deliverability Tools in 2026

By Puzzle Inbox Team · May 3, 2026 · 7 min read

Cold email deliverability tools monitor and improve inbox placement. Here are 5 best deliverability tools ranked by features, accuracy, and value.

Cold Email Deliverability Tools Ranked

Cold email deliverability tools help monitor inbox placement, diagnose issues, and improve reply rates. Here are 5 best.

1. GlockApps — Best Placement Testing

$59-149/month. Industry standard for inbox placement testing. 50+ seed addresses.

2. Folderly — Best Comprehensive Platform

$82-110/inbox. Comprehensive deliverability platform with diagnostics and remediation.

3. Mailreach — Best Bundled with Warmup

$25/inbox. Warmup + deliverability reports combined.

4. EmailGuard — Best Continuous Monitoring

$49-149/month. Automated monitoring with alerts.

5. Google Postmaster Tools — Best Free Option

Free from Google. Gmail deliverability data from source. Essential for Gmail cold email.

Deliverability Tool Stack

Most cold email operations use combinations: Google Postmaster Tools (free, continuous), GlockApps (periodic testing), Mailreach or similar (warmup).

Best cold email deliverability approach: Google Postmaster Tools + GlockApps + pre-warmed inboxes covers 90% of deliverability needs without Folderly premium pricing.