MailStone Gmail Extension icon

MailStone Gmail Extension

FeaturedEstablished publisherManifest V3 Free
View in Chrome Web Store Data as of 17 Oct 2026

Certify your emails on the blockchain directly from Gmail — in one click.

Users
13
−4 in 30 days
Rating
0.0 / 5
unchanged in 30 days
Ratings
0
0 in 30 days
Store rank
#178K
#148K among extensions
Version
2.2.0
updated 13 Oct 2026

Users

monthly, 3 years
11019Aug 2023Oct 2024Oct 2026
Latest, 17 Oct 2026: 13 usersMove the mouse over the chart for any month

Ratings count

monthly, 3 years
001Aug 2023Oct 2024Oct 2026
Latest, 17 Oct 2026: 0 ratingsMove the mouse over the chart for any month

The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.

About MailStone Gmail Extension

MailStone for Gmail lets you send two kinds of legally useful email without leaving Gmail: the Opposable Mail, a certified email with its evidence file, and the Electronic Registered Delivery (ERD), the electronic equivalent of a registered letter. TWO PRODUCTS, ONE BUTTON Click the MailStone button in the compose window and choose: • Opposable Mail — your message reaches its recipients as usual; MailStone timestamps it, anchors it on the blockchain and keeps an evidence file of what you sent, to whom and when. • Electronic Registered Delivery — your recipient is identified, then accepts or refuses the delivery; every step is timestamped and gathered in an evidence file, enforceable under eIDAS. HOW IT WORKS Opposable Mail 1. Compose an email in Gmail 2. Click MailStone, choose Opposable Mail and pick a MailStone folder 3. The extension adds the folder's address in Bcc 4. Send: your evidence file is built on MailStone servers Electronic Registered Delivery 1. Compose an email and add your recipients in the To field 2. Click MailStone and choose Electronic Registered Delivery 3. Send as usual: a notification confirms that your delivery was taken into account 4. Follow its status (delivered, accepted, refused) from your MailStone space WHY USE IT ✔ eIDAS-qualified timestamping and blockchain anchoring ✔ Up to 50 recipients in one registered delivery ✔ Your plan usage and registered-delivery credits shown in the extension ✔ Everything happens in Gmail: no copy-paste, no extra tool PRIVACY The extension never reads or stores the body of your emails. It keeps your MailStone account address and session in the browser to call the MailStone API. For a registered delivery, it reads the recipients of the message you are composing to prepare the delivery; Cc and Bcc recipients are flagged as not covered. Nothing is shared with third parties. Full policy: https://www.mailstone.io/terms

Growth

WindowUsersChangeRatingsRating
7 days+2+18.2%00.00
30 days−4−23.5%00.00
6 months+3+30.0%00.00

Version history

7 versions recorded
2.2.013 Oct 2026
2.1.230 Apr 2026
2.1.129 Apr 2026
1.1020 Mar 2024
1.922 Nov 2023
1.64 May 2022
1.515 Mar 2022

Details

Category
Workflow & Planning
First seen
15 Mar 2022
Size
209 KB
Languages
en, es, fr, pt-BR, ar
Pricing
Free
Privacy policy
mailstone.io
Support
mailstone.io
Extension ID
okinepeegedpbimkffhbkhblkephecig

Permissions and risk

Low riskimpact 2, likelihood 1
Permissions
storagealarmsnotifications
Site access
https://mail.google.com/*https://api-msv2.mailstone.io/*

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