A lead database is a maintained store of companies and the people at them, where each record carries a contact channel, firmographics, the source it came from, consent status, touch history and the date it was last verified. The maintenance is the point: a list is a snapshot, a database is a process. Across 6.5 million business addresses verified in 2026, 32.6% were confirmed valid; a database with verification on entry and a 90-day re-check runs at 70% and above.
The headline metric is reachable share, confirmed-valid records over all records. Secondary metrics are the age distribution of verified-at dates and the invalid rate by source segment, which shows which entry point is polluting the base.
The B2B leads database guide sets out the field-by-field anatomy, the decay rate per field and the 90-day loop. Subscription databases such as ZoomInfo and Apollo are sources that feed it, not substitutes for it; they hold no consent history and expire with the contract.
A 30,000-record CRM base is audited. Reachable share is 44%. Segmenting by source shows inbound at 88%, finder exports at 71%, and a 2023 bought list at 19%. The bought segment is quarantined, the finder segment is re-verified, and the next audit reports 68% reachable on a base that is 12% smaller and twice as useful.
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.