Plugins in 1999.io are basically single-page apps that have access to the server, and can do things on behalf of the logged-in user.

Through lots of factoring over many months, the code is extremely high level.

The template editor demo'd here has all the same abilities that the 1999.io app has. They run through the same JavaScript API.

We use Twitter for identity and the local server file system to store JSON files.

Very lightweight and low-tech but also quite powerful.

It's all coming together nicely.

BTW, you can try the template editor yourself, exactly as in this video. Go to my.1999.io and log in. Create a short hello world post, and do what I did in the video. It should work. ;-)