Glossary
Cold email vocabulary, in plain English
- Bounce
- A permanent (hard) or temporary (soft) delivery failure. >2% hard bounces will damage sender reputation.
- Deliverability
- The likelihood that an email lands in the Inbox rather than Spam or Promotions.
- DKIM
- DomainKeys Identified Mail. A cryptographic signature added to every outbound email to prove it wasn't forged.
- DMARC
- A policy that tells receivers what to do when SPF and DKIM don't align. p=quarantine or p=reject required for Gmail bulk senders.
- Envelope sender
- The Return-Path address — where bounces go. Often different from the visible From: header.
- Reputation
- A per-domain, per-IP score maintained by each mailbox provider. Rebuilding a burned domain takes months.
- Seed inbox
- A real recipient mailbox (usually a Gmail app-password account) used to receive warmup traffic and rescue from Spam.
- SPF
- Sender Policy Framework — a DNS TXT record listing which IPs are allowed to send email for your domain.
- Warmup
- The process of gradually increasing send volume from a new domain to build sender reputation with mailbox providers.
- List-Unsubscribe
- RFC 8058 header required by Gmail's 2024 bulk-sender rules. One-click unsubscribe.