Email open rates died as a reliable metric when Apple's Mail Privacy Protection began loading tracking pixels on the reader's behalf, so an email can count as opened when nobody read it. Add stricter Gmail sender rules and AI-written inbox overload, and many GTM teams now test WhatsApp, where a read receipt means a person opened the chat.
Apple MPP fundamentally broke email open tracking. Apple's announcement says Mail Privacy Protection stops senders from using invisible pixels to learn when someone opens an email, and masks the reader's IP address (Apple Newsroom, June 2021). In practice Apple fetches the 1×1 tracking pixel itself, so an email can show as "opened" when the recipient never saw it.
The more of your list reads on Apple Mail, the more of your "opens" are machine-generated. Even Mailchimp's benchmark page warns that the accuracy of email open rates may be affected by Apple's privacy changes (Mailchimp email marketing benchmarks). In practice you cannot trust subject-line tests decided on opens, trigger sequences on opens, or read engagement from them. The core feedback loop of email outreach no longer works the way it did.
Since February 1, 2024, Google has required anyone sending more than 5,000 messages a day to Gmail to authenticate with SPF, DKIM and DMARC, support one-click unsubscribe for marketing mail, and keep spam rates reported in Postmaster Tools below 0.30% (Google's email sender guidelines). Beyond those published rules, mailbox filters weigh signals such as:
The result: cold emails from new domains with little engagement are far more likely to land in spam, and spam placement does not bounce, so senders often don't know their emails aren't being seen.
Enrichment, sequencing and AI-writing tools let any SDR generate thousands of "personalized" cold emails with little effort. More volume means buyers skim sender names and delete anything unfamiliar. No amount of AI-written personalization fixes a channel where the reader has stopped looking.
WhatsApp doesn't have the structural problems that killed email open rates:
We won't quote "before and after" numbers from teams that switched: public figures for cold WhatsApp results are rarely sourced, and yours will depend on your list and offer. What you can do is measure the metrics that still mean something, on both channels, side by side:
| Metric | ||
|---|---|---|
| Open signal | Unreliable for Apple Mail readers | Read receipts, when the recipient has them on |
| Reply rate | Replies ÷ emails delivered | Contacts who replied ÷ contacts messaged |
| Meetings per 1,000 contacts | Track it | Track it |
| Cost per meeting | Domains, warm-up tools, sequencer, data | Licence, SIMs, data; no per-message fee on a no-API tool |
Run the same list split across both channels for a few weeks. Reply rate and meetings booked per rep are the numbers that should decide where your budget goes.
The infrastructure needed for WhatsApp-first outbound at scale:
This is the layer Wassuply provides. Keep email for contacts without a phone number and for longer follow-ups.
Real read receipts. No spam folder. Warm-up and risk scoring built in. $397 lifetime.
Get lifetime access · $397Related reading: why cold email doesn't work like it used to and the real WhatsApp open rate, and where 98% came from.