tab-size

Estimated Support About

23.08% supported

Apple Mail

macOS

16
17
18
19
20
21

iOS

11
12
13
14
15

Gmail

Desktop Webmail

2022-07

iOS

2022-07

Android

2022-07

Mobile Webmail

2022-07

Outlook

Windows

2007
2010
2013
2016
2019
2021

Windows Mail

2022-07

macOS

2022-07
16.80
2

Outlook.com

2022-07
2
2024-01
2

iOS

2022-07

Android

2022-07

Yahoo! Mail

Desktop Webmail

2022-07

iOS

2022-07

Android

2022-07

AOL

Desktop Webmail

2022-07

iOS

2022-07

Android

2022-07

Samsung Email

Android

2022-07

Mozilla Thunderbird

macOS

2025-09

Windows

2025-09

ProtonMail

Desktop Webmail

2022-07

iOS

2022-07

Android

2022-07

Fastmail

Desktop Webmail

2022-07

HEY

Desktop Webmail

2022-07

Orange

Desktop Webmail

2022-07

iOS

2022-07

Android

2022-07

LaPoste.net

Desktop Webmail

2025-09

SFR

Desktop Webmail

2022-07

iOS

2022-07

Android

2022-07

GMX

Desktop Webmail

2022-09

iOS

2022-09

Android

2022-09

1&1

Desktop Webmail

2022-09

Android

2022-09

Mail.ru

Desktop Webmail

2022-07
1

WEB.DE

Desktop Webmail

2022-09

iOS

2022-09

Android

2022-09

WP.pl

Desktop Webmail

2025-09

Notes

  • 1

    Supports tab-size but doesn’t support white-space. Therefore, tab-size is not effectively visible

  • 2

    Supports tab-size but strips the tab character 	

Resources

Sponsor

Resend

Sponsored by Resend. Email for developers. The best way to reach humans instead of spam folders. Deliver transactional and marketing emails at scale.

Know something we don't?

Is any of the above data outdated? Or do you want to add a new email client to the list? Heads on to GitHub and edit the data file!

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Test it yourself

This feature was last tested on July 21, 2022.

If you want to test this feature in the same conditions as we did, you can get our test code and run a test by yourself. Make sure to follow our testing recommendations first.

View the test code