Spot the gatekeepers before you send
Sendbox checks whether a recipient's domain sits behind a Secure Email Gateway. Once flagged, you choose: skip that lead entirely, or route them through specific mailboxes set aside for SEG handling.
SEG Detection
AI Features
Domains get scanned first
Before anything sends, Sendbox checks whether the recipient's domain sits behind a Secure Email Gateway.
- SEG detection on recipient domains
- Skip SEG-protected leads
- Route through specific mailboxes
- Cleaner deliverability metrics
A look inside the Sendbox dashboard, where SEG Detection lives.
Campaigns
Campaign | Status | Leads | Sent | Opened | Replied | Positive | Bounced | |
|---|---|---|---|---|---|---|---|---|
Fintech Ops Leaders | Active | 3,600 | 2,510 | 1,620(64.5%) | 189(7.5%) | 79(41.8%) | 41(1.6%) | |
Seed Stage Founders – NYC | Active | 1,500 | 980 | 615(62.8%) | 112(11.4%) | 54(48.2%) | 14(1.4%) | |
Agency Growth Partners | Paused | 4,800 | 3,204 | 1,798(56.1%) | 176(5.5%) | 61(34.7%) | 71(2.2%) | |
Enterprise Security Buyers | Completed | 6,300 | 4,488 | 2,915(64.9%) | 402(9.0%) | 161(40.0%) | 79(1.8%) | |
Ops Leaders Q2 2026 | Draft | 760 | - | - | - | - | - |
Sidestep spam filters before you hit send
SEG detection on recipient domains
Sendbox spots Secure Email Gateways before you send, so you're never going in blind.
Skip SEG-protected leads
Exclude SEG-protected leads from a campaign automatically if you'd rather not deal with the deliverability risk.
Route through specific mailboxes
Send SEG-protected domains through mailboxes you've designated, with different sending patterns.
Cleaner deliverability metrics
Handling SEG leads separately keeps your overall campaign numbers accurate.
Step 1
Domains get scanned first
Before anything sends, Sendbox checks whether the recipient's domain sits behind a Secure Email Gateway.
Step 2
You choose the response
Two options: skip SEG-protected leads automatically, or route them through mailboxes you've designated for that kind of handling.
Step 3
Keep your reputation intact
SEG-protected domains are tougher to land in. Catching them upfront avoids wasted sends and keeps your deliverability numbers clean.
Where it fits
Prospecting into enterprise accounts
Enterprise domains often sit behind a SEG. Catch that upfront and decide whether to skip the lead or route it through a mailbox built for the job.
Protecting your deliverability numbers
SEG-protected domains tend to bounce and spam-flag more often. Skipping or isolating them keeps your overall metrics honest.
Routing SEG leads separately
Send SEG-protected domains through mailboxes with warmer reputations or different sending patterns to improve your odds.
Caught upfront, not diagnosed after the fact
A Secure Email Gateway flagged before you hit send
Most cold email tools send blind and leave you guessing why deliverability suddenly dropped. Sendbox checks recipient domains for Secure Email Gateways ahead of time, so you can skip those leads entirely or route them through specific mailboxes instead.
- Beats Instantly
- Beats Smartlead
Skip it or route it, your call
Once a SEG is detected on a recipient's domain, you get two options: skip the lead entirely, so they receive nothing from that campaign, or route them through mailboxes you've set aside for SEG handling.
Sendbox flags when a recipient's domain is protected by a Secure Email Gateway, so you can skip those leads or route them through specific mailboxes.
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