Is there a free trial?

Yes, 15 day free trial where you have access to all features of CMDK.

How many email inboxes can be used?

No limits. You can use it with as many inboxes as you want.

Do you offer refunds?

Yes. We offer refunds no questions asked, if you request a refund within 30 days of starting to use CMDK.

How do I cancel my subscription?

We use Stripe to manage payments and subscriptions, and you can cancel or manage your subscription anytime by visiting the Stripe subscription management portal.

How do you offer lifetime subscriptions?

CMDK is designed to work locally on your browser. This means we have negligible running costs and can afford to offer lifetime deals. We want to pass on the cost advantage to our users, and encourage long-term usage.

Do you have a mobile app?

We don't at the moment. But we have recommendations on the best email mobile apps. Write to us with your most important features and we will personalise the recommendation.

Why do Indian cards not work?

This is because of RBI regulations on the use of Indian cards. Go to the Indian cards payment page to purchase CMDK.

Is there a discount for education and non-profits?

Yes, please write to us at hello@cmdk.email.

Do you accept crypto payments?

Yes we accept stable coins, please write to us at hello@cmdk.email for more details.

Know when your emails are opened

See who opened your email and when. WhatsApp-style checkmarks, real-time notifications, right inside Gmail.

How it works

WhatsApp-style checkmarks

One gray check when sent. Double blue checks when opened. Visual status appears right next to each email in your inbox, just like WhatsApp.

Real-time desktop notifications

Get a Chrome notification the moment someone opens your email. Works even when Gmail is not open. Click the notification to jump straight to that email.

Smart notification types

Four categories: First Open (within 7 days), Cold Revival (first open after 7+ days), Re-engagement (re-opened after 24h+), and Old Email Reopened (30+ days). Enable only the ones you care about.

Toggle per email

Click the read receipt button in the compose toolbar to enable tracking for that specific email. Or turn it on globally so every email is tracked by default.

Works in replies and forwards

Read receipts work in new emails, replies, and forwards. Every compose window gets the tracking toggle. Track entire threads, not just initial sends.

No one knows you are tracking

The tracking pixel is invisible to the recipient. No "read receipt requested" popup. No notification to the other person. Completely silent.

Follow up at the right time

Stop guessing whether someone saw your email. When you see the blue double checks, you know they read it. Follow up when they are engaged, not when you are anxious.

Privacy-first design

CMDK does not read or store your email content. The tracking pixel only records open events (timestamp, count). Your emails stay private. Works locally in your browser.

CMDK Read Receipts vs the alternatives

Feature	CMDK	Superhuman	Mailtrack	Gmail Native
Works inside Gmail	Yes (Chrome extension)	No (separate app)	Yes (Chrome extension)	Yes
Price	From $9/mo or $169 lifetime	$30/mo (included)	Free tier, $4.99/mo+	Free (limited)
Visual checkmarks in inbox	Yes (WhatsApp-style)	No (sidebar panel)	Yes (checkmarks)	No
Real-time notifications	Yes (Chrome desktop)	Yes (in-app)	Yes (Chrome desktop)	No
Smart notification types	Yes (4 types, configurable)	No	No	No
Per-email toggle	Yes	Yes	Yes	No (request-only)
Invisible to recipient	Yes	Yes	Free tier adds branding	Asks recipient to confirm
Works in replies	Yes	Yes	Yes	No
Tracks re-opens	Yes (with count and timestamps)	Yes	Paid only	No
Part of a productivity suite	Yes (shortcuts, snippets, command bar, reminders)	Yes (full email client)	No (tracking only)	Yes (basic Gmail)
Privacy	Does not read or store emails	Reads and stores emails for AI	Processes email metadata	Google native

Common Questions

How do Gmail read receipts work in CMDK?

When you send an email with read receipts enabled, CMDK embeds an invisible 1x1 tracking pixel. When the recipient opens the email and their email client loads images, the pixel fires and CMDK records the open. You see the status change from a single gray check to double blue checks in your inbox.

Can the recipient see that I am tracking them?

No. The tracking pixel is invisible and does not trigger any "read receipt requested" popup for the recipient. Unlike Gmail's native read receipts, which ask the recipient to confirm, CMDK tracking is completely silent.

Does CMDK read my emails to provide read receipts?

No. CMDK does not read or store your email content. The only data recorded is whether the email was opened, when, and how many times. Your email content stays private and is never sent to CMDK servers.

What are the different notification types?

CMDK offers four notification types based on when the email is opened: First Open (within 7 days of sending), Cold Revival (first open after 7+ days, useful for follow-up sequences), Re-engagement (re-opened after 24h+ gap), and Old Email Reopened (re-opened after 30+ days). You can enable or disable each type individually.

How is this different from Gmail's built-in read receipts?

Gmail's native read receipts only work for Google Workspace accounts, require the recipient to manually confirm, and show no visual indicators in your inbox. CMDK read receipts work silently on any email, show WhatsApp-style checkmarks in your inbox, and send real-time desktop notifications.

How is this different from Mailtrack?

Mailtrack is a standalone tracking tool. Its free tier adds visible branding ("Sent with Mailtrack") to your emails. CMDK read receipts are completely invisible, part of a full productivity suite (command bar, snippets, reminders, shortcuts), and do not add any branding unless you opt in to a "Sent with CMDK" signature.

Can I track all emails automatically?

Yes. You can enable read receipts globally in Settings so every email you send is tracked by default. Or you can toggle tracking per email using the button in the compose toolbar.

Does CMDK have a free trial?

Yes. 15-day free trial with full access to all features including Read Receipts. No credit card required.

Have more questions? Contact Us ›

Wall of love

Loved by customers all across the world

Nice app. I like Gmail UI, but the shortcode options of Superhuman. So your app is the best of both worlds!

Brian Dainis

Literally the best email extension you could get. Amazing alternative to Superhuman. Super clean and just works. Definitely worth the price and they are super responsive to feedback.

Danny Nielsen

Solid extension that provides many of the key benefits of MUCH pricier tools. Even better that this lives in Gmail, so you can use other extensions as well.

Zachary Eisenstat

Great - simple as it says, but adds a bunch of convenient time saving features. I don't need a full on client, I just need my Gmail to be fast, and this does it.

Dilip Goswami

Really good and helpful. And the developer was even very responsive to feedback!

Dominic Roser

This is awesome. It massively speeds up and simplifies usage of Gmail. Great pricepoint too, and the developer is super active and amazing at feedback and improvements.

Brent Maxwell

Love it! This extension helps me fly through my emails so I can get out of my inbox and back to revenue producing work. And great support!

Bill Brelsford

Works like a charm! Exceptionally GREAT SUPPORT - even for as small language as Hungarian. It can totally replace Superhuman.

Zoltán Szabó

I have started using CMDK as a layer over my gmail. Once I got used to it I love it. CMDK provide real-time support - most impressive!