Lead nurturing is the practice of keeping a lead engaged with useful, relevant touches, by email, content, events or ads, between the moment they enter your system and the moment they are ready to buy. Cycles run weeks to months. Because nurture sends go to the same addresses repeatedly over a long period, the list decays while the programme runs; at the rate measured in BounceZero's decay study (only 19.2% of addresses still valid 90 days after a check), a six-month nurture track loses about a tenth of its audience to dead mailboxes unless it is re-verified midway.
Nurture is measured by progression rate (leads that move to a sales stage), engagement per touch, and unsubscribe rate. Open rate is unreliable since mail clients began pre-fetching images in 2021; reply and click are the honest signals.
Deliverability is the quiet failure. Nurture platforms suppress hard bounces automatically, but the bounces still count against the sending domain first. Re-verifying the nurture base every quarter removes the decayed addresses before they bounce.
A 9,000-contact nurture track runs for six months. Re-verified at month three, 520 addresses have gone invalid and are removed before the next send. Bounce rate stays at 0.3%; without the check it would have reached about 5% by month five and the automation platform would have flagged the account.
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.