What is a Deliverability Score?
A deliverability score is a numerical rating that indicates how likely your marketing emails are to successfully land in recipients' inboxes. It's calculated by email service providers (ESPs) and mailbox providers based on your sender reputation, authentication protocols, and engagement metrics. Scores typically range from 0-100, with higher scores indicating better inbox placement odds.
Why It Matters
In the UK marketing landscape, deliverability directly impacts campaign ROI. If emails land in spam folders, they won't generate clicks, conversions, or engagement – regardless of creative quality. Regulatory compliance also plays a role; the ICO's PECR guidelines require legitimate sending practices, and poor deliverability often signals non-compliant behaviour.
A strong deliverability score protects your sender reputation across all major UK ISPs (Virgin Media, Sky, BT) and global providers (Gmail, Outlook, Yahoo). This reputation compounds over time, affecting long-term campaign performance.
Key Factors Affecting Your Score
Authentication & Technical Setup - SPF (Sender Policy Framework) records - DKIM (DomainKeys Identified Mail) signing - DMARC (Domain-based Message Authentication) policies - SSL/TLS encryption
Sender Behaviour - List quality and engagement rates - Bounce rates (hard and soft) - Spam complaint frequency - Unsubscribe patterns
Reputation Indicators - IP warming practices for new sending IPs - Domain age and history - Listing status on blackhole lists (RBLs) - User engagement (opens, clicks, deletions without reading)
When It's Used
Deliverability scores are essential before launching any email campaign, particularly:
- New sender setup: Establishing credibility with ISPs
- Reputational recovery: After spam complaints or poor metrics
- Campaign optimisation: A/B testing to improve inbox placement
- List maintenance: Identifying deliverability issues before they escalate
- Compliance audits: Meeting GDPR and PECR requirements
Best Practices
Monitor your score regularly using tools like 250ok or Validity's Everest. Maintain engagement by segmenting inactive subscribers and cleaning lists quarterly. Always include clear unsubscribe options – UK law requires this under PECR. Warm up new IPs gradually, starting with engaged segments before broader sends.
Connect Media Group can audit your deliverability baseline and implement targeted improvements across technical setup, list hygiene, and sending practices to maximise inbox placement across your email campaigns.