Deliverability is the whole game in outbound. A brilliant message that lands in spam performs worse than a mediocre one that reaches the inbox, and most programmes fail on infrastructure rather than copy.
Never send from your primary domain
Buy separate sending domains that resemble your main one. If the reputation of a sending domain is damaged, you lose that domain rather than the one your invoices and support email depend on.
Authenticate all three records
- SPF, listing every service permitted to send on the domain.
- DKIM, so each message carries a signature the receiver can verify.
- DMARC, which tells receivers what to do when the first two fail, and gives you reporting.
Google and Yahoo now enforce these for bulk senders. Missing records are no longer a subtle reputation penalty, they are a hard filter.
Warm for three weeks before volume
Start at five to ten messages a day per inbox and increase gradually over about three weeks. Warming tools that generate artificial replies help, but genuine conversations help more. Do not skip this to hit a launch date; the domain will carry the damage for months.
Sending rules that hold up
- Thirty to fifty messages per inbox per day, maximum. Add inboxes rather than volume per inbox.
- No links in the first message. Links in a cold first touch depress inbox placement noticeably.
- Plain text formatting. Heavy HTML reads as bulk mail to filters and to people.
- Genuine personalisation in the opening line, not a merge field wearing a costume.
- A visible, working opt-out, honoured immediately and permanently.
Monitor the right signals
Open rates are unreliable now that privacy features pre-fetch images. Watch reply rate, bounce rate and spam complaint rate instead. Keep bounces under 3 percent and complaints under 0.1 percent, and pause the moment either climbs.
Legal basis, briefly
US sending follows CAN-SPAM: accurate headers, a physical address and a working opt-out. UK and EU B2B outreach generally runs on legitimate interest, which requires a documented assessment, relevance to the recipient role and an easy objection route. Keep records of why each contact was approached.
This guide is operational advice, not legal advice. Have your counsel review your programme before launch.