What I really love about Onion sites is that if they are big enough, performance engineering really becomes Tor-specific. A few examples:
- Making assets embedded as base64 (img src the header logo as base64, all CSS should be inline, etc.).
- Leveraging CSS as much as possible (if you use animations and transitions, use CSS as much as possible for these, avoid JS for them).
- Make sure your website is mostly rendered on the backend. If you're to have JS, your website should work without it.
- Security becomes REALLY fun, as in, avoid XSS, CSRF, SQL Injection attacks and any other injections as much as possible.
As someone summarizes in another comment[0], keep the chattiness as minimal as possible. By chattiness I understand they mean, pack as much data as you can in the same Keep-Alive connection. Avoid making new HTTP requests as much as possible, as each one might get assigned to a new Onion route making things slow.
If you can ship your website to the browser in a single connection, you've won.
I've always been impressed by performance of these big Onion sites, they really push the limits of software engineering creativity, given these constraints and nature of Tor.
Besides using a separate port, I would also suggest running the hidden service on a non-127.0.0.1 bind address, just in case you ever host something else on that port and forget to disable the hidden service:
> HiddenServicePort 80 127.13.37.1:8080
> listen 127.13.37.1:8080;
This way, strangers won't be able to connect to a service bound to 127.0.0.1, should you ever decide to re-use the port and forget to disable the hidden service.
You'll also need to use separate ports and/or bind addresses if you host multiple hidden services and don't want people to correlate them - if nginx doesn't match the Host header, it will serve whichever site comes first alphabetically.
Besides accessing your page are random people able to use your server as an exit node? Am I thinking the right thing... I met someone in Switzerland that was hosting anonymous exit nodes to some anonymous network and he said that it was a pain having to explain what was happening to the police.
Exit node are an entirely optional part of the Tor network. If you run a relay or a hidden service you are not forced to participate in the exit node side of things. It's also not recommended to combine these roles because it could have security implications for your hidden service.
1. If you want to improve page load speed you need to buy a HTTPS certificate so you are not limited to HTTP/1.1. Multiplexing in HTTP/2 is important for getting sites to load fast.
2. You can set the HiddenServiceExportCircuitID configuration to pass the circuit id to your web server for telemetry or anti abuse purposes. Otherwise your logs will say that all users are coming from the same IP.
Imagine if normal people could install a single normal application and just run a website from a folder. CLI makes it more difficult than hosting a normal website. Typing commands you don't understand doesn't seem all that of a great idea.
Nice thing is you skip port forwarding entirely, which matters a lot if your ISP has you behind CGNAT. Curious how people handle uptime though, since a hidden service going down isn't something you notice until someone tells you.
Ran a small onion site for a couple years and the nice part is you never touch a public IP or a cert. Downside is onion v3 addresses are impossible to share verbally and the latency makes anything chatty feel broken. Static pages only, honestly.
- Making assets embedded as base64 (img src the header logo as base64, all CSS should be inline, etc.).
- Leveraging CSS as much as possible (if you use animations and transitions, use CSS as much as possible for these, avoid JS for them).
- Make sure your website is mostly rendered on the backend. If you're to have JS, your website should work without it.
- Security becomes REALLY fun, as in, avoid XSS, CSRF, SQL Injection attacks and any other injections as much as possible.
As someone summarizes in another comment[0], keep the chattiness as minimal as possible. By chattiness I understand they mean, pack as much data as you can in the same Keep-Alive connection. Avoid making new HTTP requests as much as possible, as each one might get assigned to a new Onion route making things slow.
If you can ship your website to the browser in a single connection, you've won.
I've always been impressed by performance of these big Onion sites, they really push the limits of software engineering creativity, given these constraints and nature of Tor.
--
[0]: https://news.ycombinator.com/item?id=49872320
EDIT: Formatting of bullet points.
To make sure once in the .onion, you never leave the .onion
> HiddenServicePort 80 127.13.37.1:8080
> listen 127.13.37.1:8080;
This way, strangers won't be able to connect to a service bound to 127.0.0.1, should you ever decide to re-use the port and forget to disable the hidden service.
You'll also need to use separate ports and/or bind addresses if you host multiple hidden services and don't want people to correlate them - if nginx doesn't match the Host header, it will serve whichever site comes first alphabetically.
1. If you want to improve page load speed you need to buy a HTTPS certificate so you are not limited to HTTP/1.1. Multiplexing in HTTP/2 is important for getting sites to load fast.
2. You can set the HiddenServiceExportCircuitID configuration to pass the circuit id to your web server for telemetry or anti abuse purposes. Otherwise your logs will say that all users are coming from the same IP.
https://blog.cloudflare.com/cloudflare-onion-service
(There are solutions for CGNAT - https://david.alvarezrosa.com/posts/self-hosting-behind-cgna...)