After releasing my Perl client (le.pl) and a library (Crypt::LE) some time ago I have seen those running fine on multiple platforms, including Mac OS X and Windows (ActiveState now has appropriate PPMs, but I believe they are only available for those with ActivePerl business license).
Unfortunately I found that one particular feature, which often puzzles people, was not quite working in Windows environment. That feature is CSR generation. Long story short, I have created a page to generate CSRs online (In-browser, no server-side).
One thing leads to another and I ended up creating a whole in-browser client. I have tried to make it as easy to use and straightforward as possible, so even those who never heard the word “openssl” could just get the certificate with a few clicks.
The client is available at https://ZeroSSL.com as “Free SSL Certificate Wizard”.
If you’d like to see it translated in your language, you can download a translation template at https://zerossl.com/translations/template.txt and send it back to me translated (by using a contact form on site or directly sent to “info”). Please specify the language name or the language ISO code in the subject and keep the original template formatting including meta-constructs such as ‘Section’ and ‘Item’ intact.
P.S. Almost forgot - every tool there should be also rendering and working fine on mobile devices, such as smartphones. However, some functions might take a bit of time - for example generating a new CSR with 4096 bits key may take between 1 and 2 minutes on the last-year phones.
P.P.S. I would also appreciate some feedback on whether using this in-browser client was straightforward and easy and whether it worked for you or not. Since it is fully client-side, I cannot know whether it worked for someone or not (once the page is loaded, there is no communication between your browser and ZeroSSL server, only between your browser and Let’s Encrypt API). If you encounter errors or something in the process is not clear - let me know (for example via a contact form on ZeroSSL index page).