Never guess an email address

A guessed address is a bounce you paid for with your sender reputation. This decides, per account, whether an address may be sent to at all.

The play

1. Take only what was published. An address found on their site, in a registry, on a verified data source, or given by a person is a contact. An address you assembled from a name and a domain is a hypothesis.
2. Check the domain can receive mail before you queue anything. A lookup for mail records — falling back to the address record — costs nothing and catches the dead domain that a scraper happily handed you. A lookup that fails to answer is not a dead domain: retry later, never suppress on a timeout.
3. Rank the role inboxes you did find. Sales-flavoured first (comercial@, vendas@, sales@, partnerships@), then neutral (contato@, contact@, hello@), then support (sac@, atendimento@, support@, faleconosco@). The first is a door; the last is a ticket queue.
4. Write differently to a reception desk. With no named human, open by asking to be routed to whoever owns this, in one line, and make the note easy to forward. Pitching a shared inbox as though it were the decision maker is how a real company marks you as spam.
5. When there is no address, route, don't invent. A public LinkedIn, WhatsApp or Instagram profile is a channel; a person you can name and reach through a colleague is a channel; silence is a channel too. Mark the account unreachable by email and move it to the queue a human works.
6. Suppress permanently on a hard bounce and on a dead domain, before the next send, and keep the record so no future campaign resurrects it.

What good looks like

• The tell an experienced operator reads first: whether the address was published or assembled. Everything else — pattern confidence scores, verification vendors, catch-all detection — is downstream of that one question, and no confidence score turns a hypothesis into a contact.
• The mediocre version guesses, verifies with a checker that says "accept all", counts that as valid, and ships. Two weeks later the domain's reputation is spent and nobody can point at the day it broke, because no single send looked wrong.
• You know the output is good when the unreachable pile is large and honest. Coverage below 100% is the normal state of the world; a list where every row has an address is a list with invented rows in it. Bounce rate under 2% is the real number to defend, not coverage.

Rules

• MUST treat an assembled address as unreachable, not as low confidence.
• MUST check domain deliverability before the first send, and again if the address sat unused for weeks.
• MUST distinguish "this domain does not exist" from "the lookup failed" — only the first one suppresses.
• NEVER send to a role inbox with copy written for a named decision maker.
• NEVER retry a hard bounce, on any campaign, ever.
• NEVER report an account as reachable because a verification tool returned "accept all" — that is the domain refusing to answer, not a yes.