Look up any IP or domain and get an answer immediately.
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.
Blacklist Check Tool
Deliverability · Testing
Type an IP address or domain
Paste any IPv4 address or domain into the lookup box, it doesn't need to be connected to your Sendbox account first.
- Lookup any address, even outside your account
- Parallel blocklist queries
- Per-blocklist breakdown
- Free for Sendbox customers
Step 1
Type an IP address or domain
Paste any IPv4 address or domain into the lookup box, it doesn't need to be connected to your Sendbox account first.
Step 2
Lookup queries blocklists in parallel
The query fans out across every major email blocklist at once, so results come back in seconds instead of the minutes a sequential check would take.
Step 3
Read the score and per-list breakdown
A single 0-100 health score gives you a quick read, and a per-blocklist breakdown is there if you need to know exactly which list flagged the asset and what delisting process applies.
Where it fits
Vetting a domain you are about to buy
A domain you inherit also inherits any listings that came with it. Run the lookup before buying to avoid paying for a domain that already needs delisting work.
Diagnosing a deliverability drop
If one campaign's open rates suddenly crater, the lookup can tell you within seconds whether a fresh listing on the sending IP is to blame.
Verifying a delisting request worked
After filing a delisting request, run the lookup a few hours later to confirm it actually went through before you resume sending.
A lookup tool, distinct from a monitoring service.
A free lookup tool, not a pay-per-query API plan
Most blacklist lookup services charge per request or require an API subscription just to check a domain. Sendbox builds the lookup straight into the dashboard, free and unmetered, so it's a tool you actually reach for instead of something you ration.
- Beats Instantly
When to reach for the lookup vs the monitoring service
The lookup exists for verifying one specific asset on demand, a domain you're about to buy, an IP a colleague flagged, a sending address you suspect is causing a problem.
- Continuous monitoring handles the ongoing surveillance for assets already sitting in your account.
- They're different tools solving different jobs, and most teams end up reaching for both at different moments.
Per-blocklist visibility, not just a score
The 0-100 score gives you the fast answer, while the per-blocklist breakdown gives you the actionable one.
- Which specific list flagged the asset determines which delisting workflow applies, since every major blocklist runs its own removal process, and the lookup surfaces that detail instead of hiding it behind a single number.
A direct lookup with an answer right away.
Lookup any address, even outside your account
No need to add the IP or domain to Sendbox first, run the lookup on anything you're evaluating, vetting, or troubleshooting.
Parallel blocklist queries
Queries fire concurrently across every major list, returning results in seconds instead of the minutes a sequential check would take.
Per-blocklist breakdown
See precisely which lists flagged the asset, so the right delisting workflow is obvious.
Free for Sendbox customers
No per-query fees, no monthly cap, and no API plan to negotiate.
No. The lookup accepts any IP address or domain, including ones that aren't part of your Sendbox account at all, which is exactly what makes it useful for vetting a domain before you buy it or checking an asset you don't even own.
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