About Henri Sivonen

Photo of Henri Sivonen’s faceI am a software developer based in Helsinki, Finland. I work for Mozilla (but opinions expressed on this site are my own, etc., etc.). I mainly work on stuff around the markup parsers in Firefox. I also maintain an HTML5 validator. I participate in the HTML Working Group of the W3C.

In 2007, I graduated as Master of Science (Technology) from Helsinki University of Technology, Department of Computer Science and Engineering. I wrote my master’s thesis about HTML5 validation.

Contact Info

My primary email address is hsivonen@hsivonen.fi. Previously, I have used the email address hsivonen@iki.fi, which remains forwarded to hsivonen@hsivonen.fi.

However, I’m constantly near email bankruptcy, so other ways of communication are likely to work better. For questions about Firefox or Gecko, please consider using the dev-platform mailing list. For questions about HTML5 validation or the validator, please consider using the WHATWG help list instead of emailing me directly. For short things, tweeting to @hsivonen on Twitter or finding hsivonen on the #whatwg IRC channel on Freenode works better than email.

Please don’t email me about link exhange proposals or about translations whose main purpose is to get me to link to a particular site. I don’t participate in SEO schemes.

Finding Me on Various Services

FacebookI am not on Facebook
Google Docshsivonen@gmail.com
LinkedInI am not on LinkedIn


Starting from the beginning of July 2013, I intend to use the following key for code signing. (The master key is only for key signing. There is a signing subkey for other signatures—particularly code signing.) This key is available (insecurely; you need to check the fingerprint) via DNS PKA (gpg --auto-key-locate pka).

pub   4096R/34296AC0 2013-07-03 [expires: 2018-07-02]
      Key fingerprint = 3E95 6FC6 CE0B CAA8 F509  D291 A429 3004 3429 6AC0
uid                  Henri Sivonen <hsivonen@hsivonen.fi>
sub   4096R/C0448B11 2013-07-03 [expires: 2016-08-06]
sub   4096R/3B957B34 2013-07-03 [expires: 2016-08-06]

Prior to July 2013, I used the following key (the master key itself) for code signing.

pub   1024D/4BF78053 2008-02-26 
      Key fingerprint = F48B 82DF CB8E C84C 5418  01FC CEE1 2226 4BF7 8053 
uid                  Henri Sivonen <hsivonen@iki.fi> 
sub   2048g/1E6BCBC3 2008-02-26

For completeness, I have signed transition statement.

For work stuff, I have yet another key:

pub   2048R/5595F98A 2013-05-13 [expires: 2018-07-07]
      Key fingerprint = 7D46 8A17 0D58 BDF1 4AF4  14D0 59F7 DEA1 5595 F98A
uid                  Henri Sivonen <hsivonen@mozilla.com>
sub   2048R/EE800EA1 2013-05-13 [expires: 2016-08-06]
sub   2048R/46FA46AC 2013-07-08 [expires: 2016-08-06]


For authorizing me for SSH access: SSH public key (GPG signature)