If you've been following our release notes, you know that we have been working towards full HTTPS support on the Archive for a while now. Today, we're happy to announce that beginning on October 4th, all connections to the Archive will use HTTPS by default.
If you use a modern browser, you won't have to do anything -- we'll just flip a (virtual) switch to enforce a secure connection between your browser and our servers. As a result, all AO3 pages will display a lock symbol and/or a friendly little https:// in the address bar of your browser. Old http:// links to the Archive will automatically redirect to the secure version.
For users who might have trouble accessing secure websites, we will continue to provide HTTP access to the Archive -- via insecure.archiveofourown.org -- for as long as necessary. (You might still run into the odd HTTPS link on the site, for example when downloading a work as a PDF, MOBI, or EPUB file.)
We don't expect any downtime during this transition, and you shouldn't notice any changes. Just to be on the safe side, we will monitor our servers and firewalls and might temporarily revert back to HTTP mode should we notice any problems.
Please keep an eye on the @AO3_Status Twitter account for more updates as we get closer to the switch.
Happy (secure) browsing!
Edit 09:24 UTC on 05 October, 2017: The update to embedded media files has been completed, but attempts to move the Archive to HTTPS were unsuccessful. HTTP will remain the default for a little while longer, and we'll update you via our Twitter account when we're ready to try again.
Edit 19:16 UTC on 12 October, 2017: We successfully made the switch to HTTPS for a few days; however, the extra strain from encrypting all traffic proved too much for our servers at peak times. Until we have installed additional servers (coming soon!), HTTP will remain the default protocol. (Of course, you can still elect to use a secure connection, e.g. via a browser extension like HTTPS Everywhere.) Please follow @AO3_Status on Twitter for futher updates.
Edit 22:15 UTC on 14 October 2017: We have implemented the caching needed to reduce server strain and are currently back on the secure protocol by default. We believe we'll be able to remain on HTTPS, but if it proves too much, we will switch back until our new frontend servers arrive.