You've written the perfect outreach email. Your targeting is spot-on. The hiring signal is fresh. And the email lands in spam. It's the most frustrating problem in recruitment BD — and it's almost entirely preventable with proper setup.

This guide covers the technical and operational steps to keep your outreach emails out of spam folders.

The Three DNS Records You Must Have

Email deliverability starts with three DNS records: SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance). SPF tells receiving mail servers which servers are allowed to send email from your domain. DKIM adds a cryptographic signature proving the email hasn't been tampered with in transit. DMARC ties SPF and DKIM together and tells receiving servers what to do with emails that fail authentication. Without all three configured correctly, Gmail and Microsoft 365 are increasingly likely to flag your emails as suspicious or route them to spam.

SPF

Add a TXT record to your domain's DNS that lists all servers authorised to send email on your behalf. If you send via Gmail, your SPF record must include Google's servers. If you also use an outreach platform, its servers must be included too.

DKIM

Your email provider generates a public/private key pair. The public key goes in your DNS as a TXT record. Every outgoing email is signed with the private key. The receiving server checks the signature against the public key.

DMARC

Start with a monitoring policy (p=none) to see what's happening, then move to quarantine (p=quarantine) and eventually reject (p=reject) as you confirm everything is properly aligned.

Inbox Warmup

A new email inbox has no sending reputation. If you immediately start sending 50 outreach emails per day from a fresh inbox, email providers will flag it as suspicious behaviour. Inbox warmup is the process of gradually building sending reputation by exchanging emails with trusted addresses over 2 to 4 weeks. Warmup emails are opened, replied to, and occasionally moved from spam to inbox — all signals that tell email providers the address is legitimate. Most outreach platforms include automated warmup; if yours doesn't, do it manually by exchanging real emails with colleagues and contacts for at least 2 weeks before launching campaigns.

Warmup Timeline

  • Week 1: 5-10 emails per day (warmup exchanges only)
  • Week 2: 10-20 emails per day (mix of warmup and light outreach)
  • Week 3: 20-30 emails per day (mostly outreach, some warmup)
  • Week 4+: 30-50 emails per day (full outreach, ongoing background warmup)

Send Volume and Timing

  • Daily limit: cap at 30-50 emails per inbox per day for established inboxes. New inboxes should stay under 20.
  • Send timing: business hours in the recipient's timezone (typically 8am-5pm AEST/AEDT for Australian prospects). Emails sent at 3am look automated.
  • Multiple inboxes: if you need higher volume, spread across multiple inboxes rather than pushing one inbox past 50/day.
  • Weekend sends: avoid. Open rates drop and spam filters are more aggressive on weekend sends for B2B email.

Bounce Handling

Hard bounces (invalid address) damage your sender reputation immediately. Soft bounces (mailbox full, temporary error) are less damaging but should be monitored.

  • Auto-pause threshold: if bounce rate exceeds 2% for a campaign, pause and clean your list before continuing
  • Remove hard bounces immediately: never attempt to re-send to a hard-bounced address
  • Verify before sending: use an email verification service to check addresses before adding them to a campaign. This is the single most effective thing you can do for deliverability.

Content That Triggers Spam Filters

  • Excessive links (more than 2 in a cold email)
  • Image-heavy emails with minimal text
  • Spam trigger words (surprisingly, words like "free" and "offer" matter less than people think — low engagement is the real trigger)
  • Tracking pixels in every email (some platforms add invisible tracking pixels; receiving servers can detect these)
  • Sending from a free email domain (gmail.com, outlook.com) for business outreach

FAQ

How long does inbox warmup take?

Minimum 2 weeks for a new inbox, 3 to 4 weeks for best results. Don't rush it — one spam complaint during warmup can set you back further than the time you saved.

My emails are going to spam. What do I check first?

In order: (1) SPF, DKIM, and DMARC records configured correctly, (2) sending volume not exceeding 30-50/day per inbox, (3) bounce rate below 2%, (4) reply rate above 1% (low engagement triggers spam filters), (5) email content (too many links, tracking pixels, or formatting).

Should I use my personal email or a separate domain for outreach?

Use a separate domain or subdomain for outreach campaigns. If your outreach domain gets flagged, it doesn't affect your primary business email. Example: use outreach.yourdomain.com.au instead of yourdomain.com.au.