Early access · no Gmail permission required
Know what happened to the email you sent.
MailSignals shows you when your Gmail messages are opened, clicked, replied to or bounced, with the reason behind every verdict. It asks for no access to your mailbox, because it never needed any.
- No Gmail permission, ever
- A reason behind every verdict
- Your own opens are not counted
- Nothing sold, shared or trained on
- ✓✓ Ada Lovelace Proposal: analytics engine, phase two — Attached the revised scope and the numbers we discussed 10:42 Opened twice · last 14 minutes ago · through a mail proxy, so the count is a lower bound
- ↩ Grace Hopper Re: Compiler talk on Thursday — Yes, 3pm works. I will bring the slides 09:15
- ↗ Noor Haddad Onboarding checklist for the pilot — Everything you need is in the doc linked below Yesterday
- ✓✓ Kenji Sato Invoice 0142 — Payment terms as agreed, 30 days Yesterday
- ✓ Priya Raman Quick question about the API limits — Before I commit to the batch size Mon
- ✕ ops@oldvendor Renewal — Following up on the quote from March Mon
Why it exists
Every other Gmail tracker asks to read, send and delete your mail.
They ask because their features need it: rebuilding a group email into one message per recipient, or swapping the pixel out of your Sent copy, both go through the Gmail API. MailSignals does its work inside the Gmail page instead, so sign-in asks for your name and address and stops there.
| Commercial Gmail trackers | MailSignals | |
|---|---|---|
| Access to your mailbox | Read, compose, send and permanently delete all your mail | None. Sign-in asks for openid, email and profile |
| Google security review | Annual CASA Tier 2 assessment, because the scope is restricted | Not required, because nothing restricted is requested |
| Why a tick is green | A tick | A classification, a confidence and a one-sentence reason |
| Apple Mail Privacy Protection | Counted as a read, or dropped, silently | Labelled "delivered, open unconfirmed" and not counted |
| Cost | $36–72 per user per year | Free during early access |
The difference
Every number is defensible in one sentence.
A pixel request tells you far less than a green tick implies. Gmail fetches every image through a proxy. Apple downloads images on delivery, before anyone reads. Corporate gateways follow every link. Your own Gmail fetches the pixel too.
So every recorded hit gets a verdict from a 16-rule classifier, a confidence, and a plain-English reason shown as body text next to the event, followed by a "Who" line. An Apple prefetch is called a prefetch. A proxied open is called a lower bound. A client we cannot recognise is recorded and counted nowhere.
Replies beat clicks beat opens, and the interface is built to say so.
The rules, in order, with their confidences →- +0.6 s Your own view Pixel loaded Your own Gmail loaded the image while showing the copy in your Sent folder. Who: You.
- +3 s Delivered, open unconfirmed · 80% sure Pixel loaded Apple Mail Privacy Protection downloaded the image on delivery. The message reached the device, but we cannot tell whether it was read. Who: Nobody yet: the recipient's mail app fetched it on delivery.
- +14 min Opened (proxied) Pixel loaded Gmail loaded the image through its proxy while showing the message. Gmail hides the reader's device and location. Who: Gmail hides who read it. The recipient — or you, if you opened this on a device without MailSignals.
- +1 d 3 h Opened Reply received A reply arrived in this thread. Who: The recipient, on their own device.
How it works
Nothing changes about how you send. Three things happen underneath.
You press Send
The extension plants a 42-byte pixel, linkifies URLs you typed as text, signs eligible links, and registers the message before Gmail acknowledges the send. If any of that fails, the mail goes out unchanged.
Someone opens it
Their client fetches the pixel or follows a link. The endpoint answers first and records second, classifies the request against what it knows about proxies, prefetchers, scanners and you, and writes an event with its reason.
You find out
A green tick in Gmail within a minute, a desktop notification if you asked for one, a daily digest if you prefer, and a dashboard showing the whole history with every verdict justified.
Features
What it does, and what it refuses to claim.
Open tracking
A 42-byte pixel per message, shown in Gmail as checkmarks, and counted only when a person was plausibly behind the fetch.
Read more →Honest classification
Every hit gets a verdict, a confidence and a one-sentence reason. An Apple prefetch is called a prefetch, not a read.
Read more →Self-open suppression
Your own reads of your Sent folder are recognised and withdrawn, on desktop, without touching the Gmail API.
Read more →Link tracking
Signed redirects that survive image blocking, typed URLs included, with scanner clicks kept but counted separately.
Read more →Replies and bounces
A reply on a tracked thread and Gmail's own delivery-failure notice, both read from the Gmail page.
Read more →Alerts and digest
First open, clicks, replies, bounces, hot threads, revived threads and follow-ups, as desktop notifications, Gmail toasts or a daily email.
Read more →Dashboard
Open and reply rates, a best-time-to-send heatmap, per-contact engagement, and a timeline that justifies every verdict.
Read more →Agent API and MCP
Mail an AI agent sends through the Gmail API gets the same tracking, with every policy decision still made server-side.
Read more →The hardest problem
It does not turn green when you open your own Sent folder.
The most common complaint about every tracker on the market. When you look at a sent message, your Gmail fetches the pixel through the same proxy a recipient would use: same user agent, same IP, same referrer. Nothing in the request tells the two apart.
MailSignals knows two things the request does not say: the extension can see what is on your screen, and it knows which network the message was sent from. Any pixel hit within 20 seconds of you viewing the message is withdrawn as your own, in whichever order the two arrive, with a backstop for the race in between. A direct fetch from your own network with a Gmail referrer is recognised without any of that.
On a phone without the extension the ambiguity is real and the product says so: the dashboard offers "That open was me", and after two of those it points you at the one setting that removes the problem at the source.
The four paths, and the one that only appeared in production →Desktop notifications, filtered by your preferences and quiet hours, computed in your timezone rather than the machine's. An alert that fires on a scanner's fetch would teach you to ignore alerts, so only counted events can raise one.
Privacy
Never the body. Never a full IP address. Never sold.
The people who open your email did not install anything and did not agree to anything, so what is kept about them is the minimum that still lets the classifier work.
- A timestamp, the user agent, an IP truncated to a /24 and a salted hash of it. The full address exists only as a local variable in the request handler and is never written.
- No location, even though a setting for it exists; no code path records one today, and the privacy page says so.
- For mail you send from Gmail in your browser, the body is never read, transmitted or stored.
- Your data is never sold, shared, or used to train anything. There is no analytics or advertising service anywhere in the product.
- A do-not-track domain list, an optional disclosure footer and a per-message off switch, so you can comply with ePrivacy and the CNIL where you must.
Notes for the morning: the numbers are in the shared sheet and the summary is below.
Early access
Free while we onboard the first users.
- Every feature on, nothing capped
- Free
- Nothing to enter, nothing to cancel
- No card
- Gmail permissions requested
- 0
- History, not the first open or seven days
- Unlimited
Pricing arrives before general availability and early-access users hear it first. What that means →
Questions
The five people ask first.
Why does it not just use the Gmail API?
Because a Gmail scope is a restricted scope, and asking for it means asking you to let software read, send and permanently delete all your mail. Trackers that take it do so to rebuild group emails and rewrite your Sent copy. We decided that access is not ours to hold: everything MailSignals needs is already on screen in front of you. The trade is that replies, bounces and your own reads have to be recovered from the page, which is most of what makes MailSignals interesting.
What do the checkmarks mean?
Grey ✓ is sent. Green ✓✓ is opened by a person, as far as the evidence supports. Amber ✓✓ is delivered to Apple Mail, which loads images before anyone reads. ↗ is a link clicked, ↩ is a reply, ✕ is a bounce. Hover any of them and the tooltip says what is known and, when the answer is uncertain, why.
How do I start?
Sign in with Google, add the extension to Chrome or Edge, and send. Nothing needs configuring first. MailSignals is in early access, so accounts are opened as we onboard people rather than instantly.
Can other people on my machine end up in my history?
No. A browser can hold several Gmail accounts and the extension runs in all of them, so only a Gmail address you have explicitly linked to your account is tracked. The server refuses everything else before writing anything.
Is there a catch?
Two honest ones. Reply detection reads the Gmail page, so a reply on a thread you never open can be missed; there is a manual mark for that. And on a phone without the extension, your own reads of your sent mail look like a recipient's, so Gmail's "ask before displaying external images" setting is the real fix. Both follow directly from refusing mailbox access, and we would rather name them than let you find them.
See what happened to your last email.
MailSignals is in early access and free while it is. Sign in with Google, add the extension to Chrome or Edge, and the next message you send is tracked.