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Deliverability

Acceptance Rate

The percentage of sent emails accepted by receiving mail servers, before inbox placement decisions.

Definition

Acceptance rate measures the percentage of emails that receiving mail servers accept for processing. This occurs before spam filtering and inbox placement. A high acceptance rate means servers are not outright rejecting your emails at the connection level. Low acceptance rates indicate serious deliverability issues like IP blocklisting or authentication failures.

Why It Matters

Acceptance rate is the first hurdle in email delivery. If servers reject your emails outright, they never even have a chance at the inbox. Monitoring acceptance rate helps identify infrastructure problems before they become major deliverability crises. A sudden drop indicates urgent action needed.

How It Works

When your email server connects to a recipient's server, it can accept or reject the connection and message. Rejections happen due to blocklisting, authentication failures, rate limiting, or policy violations. The acceptance rate is calculated as (accepted emails / total sent) × 100. Aim for 98%+ acceptance rate.

Best Practices

  • 1Maintain proper SPF, DKIM, and DMARC authentication
  • 2Monitor your IP reputation across major blocklists
  • 3Keep bounce rates low by cleaning your list regularly
  • 4Warm up new IPs gradually before high-volume sending
  • 5Investigate any sudden drops in acceptance immediately

Frequently Asked Questions

A healthy acceptance rate is 98% or higher. Below 95% indicates problems requiring investigation. Below 90% represents a serious deliverability crisis that needs immediate attention.

Acceptance rate measures server-level acceptance. Delivery rate accounts for all successful deliveries including those to spam folders. You can have high acceptance but low inbox placement if your emails are accepted but filtered to spam.