The deliverability stack, built in
Most platforms sell warmup, validation, and placement testing as add-ons. Sendbox bundles the entire deliverability suite on every plan, on infrastructure that's yours alone.
Infrastructure
Dedicated IPs
Each Sendbox account gets an IP address that belongs to it exclusively. That means your inbox placement rises and falls with your own sending habits, never with whatever a stranger sharing your plan did last week.
Isolated Infrastructure
Isolated infrastructure underpins every Sendbox account: your IPs, your sending activity, and your reputation all stay separate from every other user on the platform.
Human-like Warmup
Sendbox warmup builds sender reputation gradually by trading real emails with real accounts, generating opens, replies, and spam-folder rescues on its own. If mailbox health starts to dip, warmup automatically throttles volume and shifts timing to protect it.
Monitoring
Mailbox Health Visibility
Spot the mailboxes that are starting to slip, pull them from rotation, run warmup, and bring them back healthy.
Bounce Tracking
Sendbox logs the delivery status of every email that goes out, tracking bounces both by campaign and by mailbox so you know exactly where a problem is originating and which list or mailbox needs your attention.
Blacklist Monitoring
Every sending IP and domain on your account gets watched around the clock through continuous blacklist monitoring. The moment a listing appears, you're alerted, well before it shows up as a dip in reply rates. What actually matters isn't the scan itself, it's how little time passes between a listing happening and you finding out.
Testing
Inbox Placement Testing
Send your email to a set of seed accounts and see exactly where it ends up, inbox, spam, or somewhere in between. Sendbox reports back an inbox rate, a spam rate, and an overall score so you know whether you're actually ready to launch.
Blacklist Check Tool
An on-demand lookup for one IP or domain at a time: type in the address and get back its listing status across every major blocklist, plus a 0-100 health score. It's built for one-off verification rather than ongoing background monitoring.
Email Validation
Every email address is validated automatically when you import leads. Sendbox categorizes each address as deliverable, undeliverable, risky, or unknown with confidence scores so you can decide what makes the cut.
Ready to land in primary?
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Every plan includes a dedicated IP. Cancel whenever you want.