Pre-warmed mailbox glossary
28 terms you will meet when buying and running pre-warmed mailboxes, in plain language.
- Aged email account
- An old email account, often a consumer Gmail account, resold after years of unrelated use. Not the same as a pre-warmed mailbox, and usually a breach of the email provider's terms.
- App password
- A 16-character password Google generates so a tool can connect to a mailbox over IMAP or SMTP when 2-step verification is on.
- Blacklist (blocklist)
- A public list of IP addresses or domains reported for spam, such as Spamhaus. Being listed can push mail to spam at many receivers at once.
- Bounce rate
- The share of sent emails that come back undelivered. Keep hard bounces under 2%, ideally under 1%, by verifying lists before sending.
- Cold email
- A first, unsolicited email to a business contact with a relevant offer. Legal in most markets when it is honest, targeted and easy to opt out of.
- DKIM
- DomainKeys Identified Mail: a cryptographic signature added to each message, verified with a public key published at selector._domainkey.yourdomain.
- DMARC
- A DNS policy at _dmarc.yourdomain that tells receivers what to do when SPF and DKIM fail to align (none, quarantine or reject) and where to send reports.
- Domain reputation
- How receivers rate a sending domain based on its history of volume, engagement and complaints. Most cold email reputation lives here.
- Global admin
- The top administrator role in Microsoft 365. The Microsoft equivalent of Google super admin; you should own it after handover.
- Inbox placement
- Where delivered email ends up: inbox, promotions or spam. Measured with seed tests.
- Inbox rotation
- Spreading a campaign across many mailboxes so each one sends a small, steady volume.
- IMAP and SMTP
- The protocols sending tools use to read (IMAP) and send (SMTP) mail from a mailbox when OAuth is not used.
- Mailbox density
- How many mailboxes share one sending domain. Three is the common convention for cold email.
- MX record
- The DNS record that says which server receives email for a domain. Needed so replies and bounces reach you.
- OAuth
- A way to connect a sending tool to a mailbox without sharing the password, by granting permission through Google or Microsoft.
- Pre-warmed domain
- A sending domain whose mailboxes have already run weeks of warmup. Since reputation is scored mostly per domain, the domain is what carries the history.
- Pre-warmed email account
- Another name for a pre-warmed mailbox.
- Pre-warmed inbox
- Another name for a pre-warmed mailbox.
- Pre-warmed mailbox
- A business mailbox on Google Workspace or Microsoft 365 that already ran 4-6 weeks of gradual warmup before handover, so it can send cold email at a conservative volume from day one.
- Secondary domain
- A domain similar to your main brand (yourbrand.co instead of yourbrand.com) used for cold email so your main domain's reputation is protected.
- Seed test
- Sending a test email to a set of monitored inboxes at Gmail, Outlook, Yahoo and others to measure inbox placement.
- Sender score
- A general term for reputation ratings of a sender. Gmail Postmaster Tools and Microsoft SNDS are the first-party views.
- Spam complaint rate
- Complaints divided by delivered emails. Google asks bulk senders to stay under 0.3% and ideally under 0.1%.
- SPF
- Sender Policy Framework: a TXT record listing which servers may send email for a domain. One record per domain, ending in ~all or -all.
- Super admin
- The top administrator role in Google Workspace. Whoever holds it controls every mailbox, password and setting on the domain.
- Tracking domain
- A custom domain used for open and click tracking links instead of a sending tool's shared one, so other senders' reputation does not affect yours.
- Warmup
- A gradual ramp of low-volume sending with positive engagement that builds a history for a new mailbox and domain, usually over 4-6 weeks.
- Warmup log
- A daily record per mailbox of warmup emails sent, received, replied and placed. The evidence that a pre-warmed mailbox was actually warmed.