Why bounce rate matters more than open rate
Major email receivers (Google, Microsoft, Yahoo) treat your bounce rate as a primary reputation signal. A bounce rate above 5% drops your inbox placement; above 10% can land your domain on a blocklist. Open rate is interesting; bounce rate is binary — it determines whether you reach inboxes at all.
The single largest cause of bounces is sending to addresses that no longer exist or were never valid. The fix is real-time email verification at the moment of enrichment, before any campaign sends.
SPF, DKIM, DMARC — the table stakes
Three DNS records that prove the email is actually from you:
- SPF — declares which servers can send mail on behalf of your domain. Receivers reject mail from unauthorized senders.
- DKIM — cryptographic signature on each message proving it wasn't tampered with in transit.
- DMARC — policy telling receivers what to do when SPF/DKIM fail. Start with p=none (monitoring), graduate to p=quarantine, then p=reject.
Without all three, your messages are likely being filtered as suspicious before they're even evaluated for content. This is a 30-minute setup that has more impact on deliverability than any copywriting change.
Domain warm-up
A new sending domain has zero reputation. Sending 1,000 emails on day one is the fastest way to land on a blocklist. The warm-up cadence:
- Week 1: 50 emails/day to engaged recipients
- Week 2: 100/day
- Week 3: 200/day
- Week 4–6: ramp to your target volume
'Engaged recipients' means recipients who reply or click. Send the warm-up emails to your existing customers, partners, or a paid warm-up service that simulates engagement.
List hygiene as ongoing discipline
Email lists decay at 20–30% per year through job changes, company shutdowns, and personal email moves. The hygiene pattern:
- Verify every address before adding to the list
- Re-verify the entire list quarterly
- Remove anyone who hasn't engaged in 12 months (sunset policy)
- Honor unsubscribes within 24 hours (legal requirement under CAN-SPAM and GDPR)
Why real-time verification matters
Most B2B data products refresh their email validity flags on a quarterly batch cycle. By the time you send, those flags can be 90 days stale. LeadGen Engine verifies at the moment of enrichment via SMTP-level handshake — the verdict reflects what's true today, not last quarter.
Frequently asked questions
- What bounce rate is acceptable?
- Under 2% for most email service providers. Above 5% triggers reputation warnings. Above 10% can result in immediate sending suspension or blocklist inclusion.
- How long does domain warm-up take?
- 4–6 weeks to reach normal sending volume. Skipping warm-up doesn't shorten the timeline — it lengthens it because you'll have to recover from a damaged reputation.
- Do I need a separate domain for cold outreach?
- Best practice yes — keep your primary domain reputation pristine for transactional and customer email. Cold outreach goes from a separate sending domain (often the apex domain's subdomain like outreach.example.com).
- How does GDPR affect cold outreach?
- EU recipients require legitimate-interest basis or explicit opt-in. The legitimate-interest path requires you to demonstrate that your contact was likely interested based on their public role and that you offer easy opt-out in every message.
- Can I bypass deliverability issues by sending from a third-party service?
- Sometimes — but their sender reputation is shared across their customer base. If another customer sends spam, your deliverability degrades. Dedicated IPs are an option at scale ($50–$200/month) but require more warm-up discipline, not less.