Deliverability best practices

Cold email deliverability is a technical skill as much as a writing skill. Follow these rules and your FlowMaticX-sent emails will land in the primary inbox, not promotions or spam.

SPF (Sender Policy Framework) — a DNS TXT record on your domain that lists which servers are allowed to send email as you.

DKIM (DomainKeys Identified Mail) — a cryptographic signature added to every outbound email, verified against a public key in your DNS.

DMARC (Domain-based Message Authentication) — a policy that tells receiving servers what to do with emails that fail SPF or DKIM.

If you don't set all three, your emails will land in spam regardless of content quality.

Gmail and Yahoo now reject bulk cold email from domains without DMARC. Outlook flags it as suspicious.

1. SPF — add a TXT record at your domain root:

v=spf1 include:_spf.google.com include:_spf.resend.com -all
(Replace _spf.google.com / _spf.resend.com with your actual sending provider)

1. DKIM — your email provider gives you 1-3 CNAME records to add. Google Workspace generates keys in Admin Console → Apps → Google Workspace → Gmail → Authenticate email. Resend generates keys in their dashboard.
2. DMARC — add a TXT record at _dmarc.yourdomain.com:

v=DMARC1; p=none; rua=mailto:postmaster@yourdomain.com
Start with p=none (monitor-only) for the first week, then upgrade to p=quarantine for another two weeks, then p=reject. Going straight to p=reject risks losing legitimate email if your SPF/DKIM has a bug.

Check your setup at mxtoolbox.com/SuperTool.aspx.

New sender reputation starts at zero. Sending 200 cold emails on day 1 will land all of them in spam and damage your domain's reputation for months.

• Week 1: 10-20 sends/day, manual or semi-automated
• Week 2: 30-50 sends/day
• Week 3: 60-100 sends/day
• Week 4+: full volume

Enable FlowMaticX's warm-up mode on new mailboxes and it enforces these rates automatically.

• Gmail personal: 500/day hard cap
• Google Workspace: 2000/day (higher with approval)
• Outlook personal: 300/day
• Microsoft 365: 10,000/day (but throttled)
• Custom SMTP (Resend/Postmark/Mailgun): provider-dependent, usually 10k-100k/day

FlowMaticX defaults to 200/day. For high-volume campaigns, connect multiple mailboxes and rotate.

Things that trigger spam filters:

• Excessive capitalisation ("AMAZING OFFER")
• Too many exclamation marks ("!!!")
• Money symbols and percent signs ("$$ 50% off $$")
• Image-only emails (text-to-image ratio matters)
• External CSS or JavaScript
• Multiple links in a single email (keep to 1-2 max)
• "Click here" anchor text
• Spam trigger words: "free", "guarantee", "no obligation", "act now", "limited time"

The AI writer in FlowMaticX is already tuned to avoid most of these, but if you customize the output, check it against the list.

Legally required in the US (CAN-SPAM) and EU (GDPR). The AI writer includes a soft opt-out by default ("happy to stop if this isn't relevant"), but for high-volume campaigns add an explicit unsubscribe link or "reply STOP" instruction.

If an email bounces, move the lead to the Lost column. Never retry — continued sends to invalid addresses kill your sender reputation fast.

FlowMaticX auto-pauses mailboxes after 5 consecutive failures to protect against this. Don't disable that safety.

Free tools:

• mail-tester.com — send a test email and get a spam score + detailed breakdown
• Google Postmaster Tools — free, shows your Gmail reputation
• Microsoft SNDS — free, shows your Outlook reputation

Aim for 9/10 on mail-tester and "Good" reputation in both postmaster tools.

The #1 mistake in cold email: sending too much too fast from a new mailbox.

If your open rates drop below 30%, pause the campaign for 3 days and reduce volume by half. Your sender reputation needs time to recover.