Email deliverability scoring for B2B lead lists

The moment a sales rep exports a lead list and queues it for an outreach sequence, they're flying blind — they have no idea what percentage of those emails will hard-bounce until their sending domain takes the hit. By then, deliverability is already damaged and the damage is permanent in the short term.

This gap persists because lead data vendors have a structural incentive to report coverage, not accuracy. Their metric is how many contacts they return, not how many work. The buyer (a head of sales or marketing ops) often never sees the bounce report — that lands with whoever manages the email tool — so the feedback loop between 'bad data' and 'vendor renewal decision' is broken by default.

Existing tools do pre-send verification, but they check syntax and MX records — they don't cross-reference against known-bad patterns from actual outreach campaigns across many senders, and they don't flag contacts that are technically valid but almost never reply because the address is a catch-all or a role address harvested from a contact page. Users report bounce rates of 50% and more from enrichment data, which is catastrophic for domain reputation. A syntax check wouldn't catch any of that.

The business case is simple: one bad campaign can blacklist a domain for weeks. That's not a productivity annoyance — it's a hard revenue impact for any team that depends on cold outbound. Every new list triggers the same risk, which means the need recurs every time a rep runs a new sequence. The buyer is whoever is responsible for not getting their company's domain flagged as spam.

What to build

Build a list-upload service that scores each contact in a B2B lead CSV against a continuously updated signal set — catch-all detection, role-address flagging, domain-level send history patterns, and cross-referenced bounce signals from anonymized campaign data — then returns a per-contact confidence tier and a list-level deliverability forecast before any email is sent.

Where to start

Start with teams that already use a specific outreach sequencer and offer a native integration that auto-scores every new contact added to a sequence — the friction of uploading a CSV manually disappears, and the value shows up in the tool they already live in.

The hard part

The confidence signals are only meaningful if you have real outreach outcome data at scale — without a large corpus of actual campaign send/bounce/reply data to train against, the scoring is just syntax checking with extra steps, and that's already commoditized.

How it makes money

Usage-based pricing per contact scored, with a monthly subscription tier for teams that process high volumes — starts with a free tier up to 500 contacts per month to drive adoption.