Cold Email Deliverability Test: Land in Inbox, Not Spam
Cold email has the highest spam risk of any sending type. Testing deliverability before each campaign is not optional — it is how you keep reaching prospects.
Why cold email needs special testing
Cold recipients have no history with your domain. Providers rely entirely on authentication, IP reputation and content signals. One bad send can tank your domain reputation for weeks.
Cold email deliverability workflow
Warm up the domain — use MailReach, Warmy or manual warmup for 2–4 weeks
Test placement — run a GlockApps test to verify the warmup worked across providers
Fix issues — address any auth, blocklist or content flags
Send in small batches — start with 20–50 emails/day and scale gradually
Re-test weekly — reputation shifts fast in cold outreach
Test your cold email setup free before you launch the campaign.
Per-provider placement — Outlook is often the hardest for cold email
SPF/DKIM/DMARC all passing
Sending IP not on any blocklist
Content clean of spam trigger words and excessive links
Evidence & transparency. Checked against public data: cold email deliverability best practices and tool documentation. Not independently tested by us: specific provider treatment of cold email. Reader should verify: current warmup tool effectiveness and testing limits. Last reviewed: June 2026.
Frequently asked questions
How long should I warm up before cold emailing?
2–4 weeks of gradual volume increase with engagement signals. Verify with a placement test before going live.
Which tool is best for cold email testing?
GlockApps for placement verification; MailReach or Warmy for the warmup phase that precedes testing.