Stop sending to addresses that don't exist.
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.
Email Validation
Deliverability · Testing
Validation runs on import
Upload a CSV or add leads by hand, and Sendbox validates every address automatically as part of the import itself. There's no separate step to remember to run.
- Validates on import
- Four-category classification
- Confidence scoring
- Catch-all detection
Step 1
Validation runs on import
Upload a CSV or add leads by hand, and Sendbox validates every address automatically as part of the import itself. There's no separate step to remember to run.
Step 2
Multi-level verification
Syntax checks catch formatting mistakes, domain and MX record checks confirm the domain can actually receive mail, and mailbox-level verification checks whether the specific address exists. Catch-all detection flags domains that accept everything.
Step 3
Results categorized with confidence scores
Every address lands in one of four categories, deliverable, undeliverable, risky, or unknown, each with a confidence score you can use to set your own threshold for what gets into your campaigns.
Where it fits
Cleaning purchased or scraped lists
Bought a list from a data provider? Validation reveals the real quality of what you paid for. A high share of undeliverable addresses tells you the data was bad.
Catch-all domain handling
Some domains accept mail to any address, which makes verifying individual mailboxes tricky. Sendbox flags catch-all domains so you can decide how to handle them.
Protecting your bounce rate
ESPs start penalizing you once bounce rates exceed 2%. Validation keeps you under that line by filtering bad addresses out before they ever bounce.
Four categories, not just pass or fail.
Validation happens on import, not a button someone forgets to click
Most platforms treat validation as a manual step that somebody has to remember to run, and often nobody does. Sendbox validates automatically the moment leads are imported, so bad addresses are already flagged before a campaign ever starts.
- Beats Smartlead
- Beats Lemlist
Four categories, not just pass or fail
Binary validation misses the nuance: an address can be technically valid yet still risky.
- Sendbox sorts every address into one of four buckets, deliverable (safe to send), undeliverable (don't send), risky (proceed carefully), or unknown (couldn't determine status), each carrying a confidence score so you can draw your own line on risk.
Catch-all detection prevents false positives
Some domains accept mail sent to any address, even ones that don't actually exist, and standard validation marks these as "valid" simply because the server accepted the connection.
- Sendbox specifically detects catch-all domains and flags them, so you know to trust that particular result a little less.
Bad addresses caught on import.
Validates on import
No separate step required. Validation runs automatically the moment leads enter your system.
Four-category classification
Deliverable, undeliverable, risky, and unknown, far more useful than a simple pass or fail.
Confidence scoring
Every address carries a confidence score, letting you decide how aggressive your filtering should be.
Catch-all detection
Domains that accept everything get flagged, so you know which validation results to trust less.
Syntax correctness, domain validity through MX records, and whether the mailbox itself exists, plus detection of catch-all domains that accept mail to any address. Every email lands in a deliverable, undeliverable, risky, or unknown category with a confidence score.
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