A product qualified lead is a user of a free tier, trial or freemium plan whose behaviour inside the product predicts purchase: hitting a usage limit, inviting a teammate, connecting an integration, or returning on several days in a week. PQLs close at 20 to 40%, the highest rate of the lead grades, and their contact data is the cleanest a company holds because the address logged in.
A PQL definition is a set of product events with thresholds, tuned against which free users later paid. In an email verification product the signals are concrete: a user who runs a bulk job near the free limit, generates an API key, or verifies lists on three separate days is far more likely to buy credits than one who checked a single address once.
The data quality edge is structural. A PQL's email address was confirmed when the account was activated, so the bounce risk that affects every other lead grade, 14.5% invalid on non-freemail lists, is close to zero here. The only decay is job change, which the product itself often reveals when logins stop.
A freemium tool has 5,000 monthly signups. 80% confirm their address, 1,100 use the product more than once, 300 hit a usage threshold within 14 days. Those 300 are the PQLs; at a 25% close rate they produce 75 customers, more than the 400 MQLs from content produce at 3%.
Verify a list or a single address. 100 free checks a month, unknowns refunded.
Verify Leads - FreeAyoub built BounceZero's 5-stage validation pipeline, its dedicated BGP-announced IP infrastructure, and the Patroni HA PostgreSQL cluster behind every verification. Previously built high-volume email delivery infrastructure. Trained at 1337 Benguerir (École 42 network, 2019). Open-source: bgp_analyzer.