Email open rate
Email open rate is the percentage of delivered emails that recipients opened, historically measured by loading a tiny tracking pixel. It has become a less reliable metric since Apple Mail Privacy Protection and similar features pre-fetch images and inflate opens, so teams increasingly treat it as a directional signal rather than ground truth.
How it works
A 1x1 tracking pixel loads when the email is rendered, registering an open. Privacy features that pre-load images on the recipient's behalf fire the pixel without a human opening the message, which is why raw open rates now read high and noisy.
Why it matters
Open rate still helps compare subject lines and spot deliverability collapses (a sudden drop can mean spam-foldering), but it should not be the primary success metric for cold outreach. Replies and meetings booked are what actually correlate with pipeline.
How Autocloz handles it
Autocloz tracks opens alongside the metrics that matter more for outbound — reply rate and positive replies — and pairs them with inbox-placement tests, so you judge a campaign on outcomes, not just an inflated open number.
FAQ
Is email open rate still accurate?
Less so since Apple Mail Privacy Protection (2021) began pre-loading tracking pixels, which inflates opens. Use open rate as a directional and comparative signal, and lean on reply rate and meetings for true campaign success.
What is a good email open rate?
It varies widely by industry and privacy inflation, but historically 15-25% was typical for cold outreach. Because the metric is now noisy, focus on relative changes and downstream reply rate rather than an absolute target.
Related terms
Mailbox warmup is the practice of gradually increasing a new email account's sending volume while generating positive engagement (opens, replies, moving mail out of spam) so mailbox providers build trust in the sender before real campaigns ramp up.
Sender reputation is the trust score mailbox providers assign to your sending domain and IP based on how recipients react to your mail — opens, replies, spam complaints, bounces and spam-trap hits. A high reputation lands you in the inbox; a low one routes you to spam or blocks you.
Email bounce rate is the percentage of sent emails that are returned undelivered. Hard bounces are permanent (invalid or non-existent address); soft bounces are temporary (full mailbox, server down). A high bounce rate signals a poor list and damages sender reputation.
A spam trap is an email address operated by mailbox providers and blocklist operators specifically to catch senders with poor list hygiene. There's no real person behind it, so any mail it receives indicates you're emailing addresses you didn't earn permission to contact.