- on the client side - JavaScript and Roberta bytecode interpreter (later re-branded as Robby virtual machine);
- on the server side - SQLite and Hopeless (in 2019 switched to MySQL+PHP).

No logins, no private boards - everybody will see what you are doing!
But I monitor activities by IP-address - just in case

http://Circuits.CC
Web-site tested on these browsers:
FireFox 16.0 and 17.0 (good experience - developed on it);
Chrome 23 (best experience);
Safari 5.1.7 (best experience) and v4.1.3 (a little slower);
Opera 9.64 (slow), 10.63, 11.52 and 12.1;
Konqueror v4.5.5 and v4.8.4;
Internet Explorer 8 and 9 (slow, but working);
And even web-browser in Android v2.3.6

Any suggestions are welcome!
P.S. Screenshot updated on December 23rd, 2012 with v0.2 - now it has a number of libraries and copy/paste feature!
P.P.S. Updated list of tested web-browsers as per May 2019:
FireFox v66.0.4 (64-bit), v60.5.1esr (64-bit), v52.9.0 (32-bit), v17, v16, people says v3.5 works too, but slow, (v66 in Windows10 was a little slow to load, but then ok);
Chrome v49.0, v23;
Safari v11.1.2, v5.1.7 and even v4.1.3 works (in MacOS X 10.4 on PowerPC G4);
Safari from iOS 12.2 (touchscreen on iPad);
Opera v58.0, v36.0, v12.11, v11.52, v10.63, v9.64 (slow);
Konqueror v4.14.25, v4.8.4, v4.5.5;
Android 2.3.6 (touchscreen);
Internet Explorer v9.0 and v8.0 also supported since November 23, 2012 (works, but slow);
Microsoft Edge (mouse & touchscreen on Win10).
P.P.P.S. Source code is available on GitLab:
https://gitlab.com/shaos/circuits_cc