A LinkedIn profile proves a person exists. It does not prove the mailbox does
Ask an email finder for someone's address and you get back a string that looks right. That string usually came from a pattern applied to a name and a domain — first.last@company.com, flast@, first@ — rather than from any evidence that the mailbox exists.
The profile and the mailbox are separate facts, and only one of them is the one you actually need before you hit send.
What a profile gives you, and what it leaves open
| Known from the profile | Unknown until the address is probed |
|---|---|
| The person exists, their current employer and the timeline of the role | Whether the address you are about to use is the one they read |
| Their title, which is what your message will be about | Whether the mailbox accepts mail at all |
| Whether they changed jobs recently | Whether yesterday's address was deactivated when they did |
The third row in that table is the expensive one. 23% of business contacts change jobs every year (ZoomInfo, 2025), and each move quietly retires an address that a stored database still lists as current.
Three answers, not two
A pattern guess has three possible fates:
- Valid — the mail server accepted a probe for that specific mailbox.
- Invalid — the mail server rejected it. Cheaper to find out now than after a bounce.
- Unknown — the domain is catch-all: it accepts every address, including ones that were never issued. A probe returns no information about the named mailbox.
Most tools collapse the third case into "verified" because an accepted probe looks like a pass. That is how a list can be billed as verified and still bounce: catch-all domains are unchanged by ignoring them.
unknown. An email finder that reports valid there is reporting the wrong thing, not a better thing.What TAPAC does with a company domain
TAPAC resolves business contacts from company websites, Discord and Telegram — the places where the address appears attached to a role — and runs an SMTP probe in the same request that returns it. Each result carries the person, the company, the title, the source the address came from, and the verification state of that mailbox.
curl -s -X POST https://tapacapi.com/v1/contacts/search \
-H "Authorization: Bearer ***" \
-H "Content-Type: application/json" \
-d '{"industry":"software","job_titles":["head of sales"],"company_size":"11-50","location":"germany","source":"website","limit":25}'
A single address can be checked on demand with POST /v1/contacts/verify. From an agent it is one tool call — npx -y @tapacapi/mcp, or the hosted endpoint at https://tapacapi.com/mcp, exposing tapac_find_contacts and tapac_status.
TAPAC is not a LinkedIn scraper. If you already have a name from a profile page, the useful next step is verifying the address before it enters a sequence — not collecting more profiles.
What verification actually buys
Lists verified at the moment of use sit at 2-5% bounce; static databases that were verified once sit at 10-35% (TAPAC, verification cost). The bounce rate you send at is a deliverability asset with a slow replacement time, which is why the check belongs in the flow that produces the address rather than in a quarterly cleanup.
Where to go next
- B2B email finder · Bulk email verification · Email verification API
- Verify email before sending · Catch-all email verification · B2B lead list
- Install the TAPAC MCP server — npx, uvx or the hosted endpoint, with the JSON block for Claude, Cursor, Codex and Windsurf.
- Compare TAPAC with Apollo, ZoomInfo, Hunter and Lusha · Pricing · Get a free API key