How Email Deliverability Works

Email deliverability depends on three layers: authentication (proving you are who you claim to be via DNS records), reputation (built over time through consistent sending and low complaint rates), and content (avoiding patterns that spam filters flag). According to Validity's 2025 research, 15-20% of legitimate business email globally never reaches the inbox, making deliverability a critical concern for any outreach-dependent workflow.

The key factors that determine whether your email reaches the inbox:

  • SPF (Sender Policy Framework) — a DNS record listing which servers may send email for your domain
  • DKIM (DomainKeys Identified Mail) — a cryptographic signature proving the email was not altered in transit
  • DMARC — a policy telling receiving servers what to do with emails that fail SPF or DKIM checks
  • Sender reputation — a score maintained by email providers based on bounce rates, complaint rates, and engagement
  • List hygiene — removing invalid, catch-all, and unengaged addresses to maintain low bounce rates

Why Deliverability Matters for Recruitment Outreach

Recruitment agencies depend on cold email outreach to win new clients and engage passive candidates. If only 80% of emails reach the inbox, a 500-person campaign effectively reaches 400 recipients. At typical recruitment response rates of 10-15%, that is the difference between 60 replies and 50 replies, directly impacting placement revenue. Agencies that invest in deliverability consistently outperform those that ignore it.

Improving Email Deliverability for Australian Agencies

Practical steps to improve deliverability:

  • Authenticate your domain — configure SPF, DKIM, and DMARC records before sending any outreach
  • Warm up new domains — gradually increase sending volume over 2-4 weeks to build sender reputation
  • Verify before sending — use email verification to remove invalid addresses and keep bounce rates below 2%
  • Monitor per-provider performance — track inbox placement rates separately for Gmail and Microsoft 365
  • Limit daily volume — start at 20-30 emails per inbox per day and increase as reputation builds

Kolvera includes built-in domain warmup, DNS health validation, per-provider deliverability tracking, and automatic bounce handling to help Australian agencies maintain inbox placement rates above 95%.