The Axvoid Tools Blog

Practical, source-backed guides on email deliverability, list hygiene, campaign testing and tracking — each one connected to a free tool you can use right now.

Measurement & Testing

Email A/B Test Sample Size: How Many Subscribers You Need for a Reliable Result

How to calculate email A/B test sample size and read significance correctly: baseline, minimum effect, power, duration and common mistakes.

6 min read

Newest tools

Recently added free tools — they run in your browser without uploading your data

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Domain Quality Snapshot

Domain age (RDAP), first Wayback snapshot, DNS, SPF and DMARC records for up to 50 domains with a stated hygiene score and CSV

Public API

Privacy Leak Checker

Check WebRTC and IPv6 leaks, time zone and language mismatches with the IP country, and the browser automation flag

Public API

What Is My IP

See your IPv4, IPv6, approximate location, provider, ASN, address class (6to4/Teredo/private) and browser info

Public API

Stateless Redirect Page Generator

Generate a small HTML page that redirects visitors to a destination encoded in the #hash, with a delay, a message and a timestamp expiry

Local