You cannot know for certain that someone read your email unless they tell you, most often by replying. Read receipts and open tracking only show that a program reported the message as opened or loaded an image, and in 2026 machines do that all the time. Treat an open as a hint, a click as a stronger hint and a reply as the only certain answer.
That sounds disappointing, but it is useful once you know what each signal can and cannot tell you. This guide walks through the signals you can get, why “opened” so often means nothing, and a practical way to read them when you are waiting on a client, a recruiter or a supplier.
The five signals, and what each one proves
When people ask whether an email was read, they usually mean one of five different things. They fail in different ways.
| Signal | What it actually records | What it does not prove | Who controls it |
|---|---|---|---|
| Delivery status | The receiving server accepted the message | That it reached the inbox rather than spam, or that anyone saw it | The recipient’s mail server |
| Read receipt | The recipient’s mail program reported the message as opened | That the person read it; it can be sent from a preview pane | The recipient, who can decline |
| Open (tracking pixel) | A small image in the email was requested | That a person was involved at all | Whoever loads images: the person, a proxy or a scanner |
| Click on a tracked link | A redirected link was requested | That a person clicked; scanners also follow links | The person or a security filter |
| Reply | The person wrote back | Nothing is missing: this is a deliberate action | The person |
The first four are technical events. Only the last one is a decision by a human. Everything else in this article follows from that difference.
What really happens when an “open” is recorded
Open tracking works with a tracking pixel: a tiny, invisible image whose address is unique to one copy of the email. When something requests that image, the sender’s tool notes the time and some technical details of the request. That is the whole mechanism. The tool never sees eyes on a screen. It sees a download.
For years, the download usually came from the recipient’s own mail program, so “image requested” was a fair proxy for “message opened”. Three changes broke that link.
Apple Mail Privacy Protection
In June 2021 Apple announced Mail Privacy Protection. In Apple’s own description, it helps users prevent senders from knowing when they open an email and masks their IP address. In practice, Apple Mail with the protection switched on loads remote images through Apple’s servers, whether or not the person ever opens the message. The sender sees an open that may never have happened, at a time that says nothing about the reader. We cover this in detail in why Apple Mail and Gmail inflate open rates.
Gmail’s image proxy
Google states that Gmail uses Google’s secure proxy servers to serve images in messages. The image is fetched by Google, not by the reader’s device, so the sender sees Google’s network instead of the reader’s, and a later reopening may not create a new request at all. Gmail can also fetch images shortly after a message arrives, before anyone looks at it.
Security scanners
Company mail filters open new messages and follow their links to check them for malware. That can produce an open and a click within seconds of delivery, with nobody at the keyboard.
Why opens are both too many and too few
The same tracking image can mislead you in both directions:
- Too many opens. Apple’s privacy proxy, Gmail’s prefetching and corporate scanners create opens without a person. One email can show several opens because each request is recorded separately: a proxy, a scanner, the reader on a phone and later on a laptop.
- Too few opens. People who block remote images, read in plain text or use a mail program that never loads the image produce no open at all, even if they read every word. Gmail’s help page also notes that it withholds images from senders or messages it considers suspicious.
So “no open” does not mean “not read”, and “opened” does not mean “read”. Both are worth remembering before you write a slightly irritated follow-up.
Read receipts are not a better answer
A read receipt asks the recipient’s mail program to send back a notice when the message is opened. Google offers read receipts only for Google Workspace accounts, and the recipient can choose not to return one. Outlook supports them in many versions, but again the recipient can decline, and many programs ignore the request entirely. A receipt can also be triggered when a message is shown in a preview pane or marked as read without being read. It is a courtesy signal, not evidence.
A practical way to read the signals
Instead of asking “was it read?”, ask “how strong is the signal, and what did the person do?”. A simple ladder works well:
- Delivered. The message was accepted by the recipient’s server. Nothing more.
- Open, likely machine. An open within seconds of sending, from a provider or scanner network, or labelled as Apple’s proxy. Ignore it for decisions.
- Open, possibly human. An open hours or days later, from a mail program on a home, office or mobile network. A hint, nothing more.
- Click, likely human. A click well after delivery, in a visible browser, on a home or mobile network. Stronger: someone wanted that page.
- Reply. Certain. The person engaged.
An example
You send a quote on Monday at 09:00.
- 09:00:04 an open from Google’s network. This is almost certainly Gmail fetching or scanning the image. It tells you the message arrived in a Gmail inbox, not that anyone saw it.
- Tuesday 18:40 an open from a mobile network. Possibly the client glancing at it on a phone. Still a hint.
- Wednesday 10:15 a click on the link to your pricing page, from a visible browser. Now there is a real sign of interest.
- Thursday no reply yet.
What to do: a short, friendly follow-up on Thursday or Friday that restates the one decision you need. Do not mention that you saw an open or a click; it adds nothing and can feel intrusive. If the reply never comes, a phone call usually settles more than another signal would.
What to stop doing
- Do not count raw opens as reads in reports. Compare periods using the same counting method, or switch to replies (see reply rate instead of open rate).
- Do not treat an instant open or click as interest. Speed is a sign of automation.
- Do not use an open as proof in a dispute. It shows that an image was requested, at most.
A word on consent and the law
Whether you may measure opens and clicks at all is a separate question from whether you may send the email. The answer depends on the country, the purpose and, in many cases, on the recipient’s prior consent. Several European data protection authorities treat tracking pixels in emails as tools that generally need consent, with narrow exceptions. We explain how this works in practice in consent-based email tracking.
How HawkOpen reads these signals
HawkOpen is an email, document and proposal tracking app made by TriStiX S.L. It is built around the idea in this article: an image request is never presented as proof that a person read a message.
- Every open and click is checked against more than 40 named rules, including Apple Mail Privacy Protection, the image proxies of Gmail, Microsoft and Yahoo, security scanners, link previews and AI agents. Each event gets a category, such as privacy proxy, proxy cache, security scanner or human, together with the rule codes behind it (how we classify opens).
- Verdicts are estimates and go no higher than “likely”. Only the recipient’s own action, such as a reply, is treated as certain.
- Tracking is off until the company’s owner or an administrator switches it on, and then only recipients with a recorded consent are tracked. Everyone else gets an ordinary email, and every tracked email tells the recipient so.
- On the Pro and Business plans, HawkOpen detects replies in connected mailboxes and can remind you when nobody has answered.
HawkOpen is currently in a controlled launch. If you want to see how a classified open looks, the FAQ on open accuracy shows the rules and their limits in detail.
Please note: This information is general and relates to HawkOpen’s features. It is not individual legal advice or an assessment of whether a specific campaign or document complies with the law. You make the decisions about your own activities and, where necessary, seek advice from a qualified professional. This does not limit any rights you have under mandatory law.