About OS Tools

OS Tools (os-tools.com) is an email verification and lead-list cleaning service built for cold email operators, agencies and founders who send outreach at volume. We started it because the lists we bought and scraped kept bouncing, and the verifiers we tried either answered from a stale database or charged full price for results marked "unknown".

What we do

Every email is checked in real time against the receiving mailbox. Risky and catch-all addresses can go through a deeper second pass that settles them as safe or invalid. We also filter scraped website lists by niche with AI, and validate phone numbers in bulk. Everything is CSV in, CSV out, up to 10,000 rows per file, with your original columns kept.

How we charge

Pay as you go. You buy a pack of credits, credits never expire, and there is no subscription. Any result we can't stand behind is refunded to your balance automatically — see our refund policy.

Who runs it

OS Tools is operated from Hong Kong SAR and governed by Hong Kong law. We don't sell or share the lists you upload. Read how we handle data in our privacy policy and trust centre, or contact us.