Lethio

Open source software, built in the evenings and mostly given away.

PCB Visualizer documents circuit boards. Kofte counts stitches. Macro Tracker is a food diary built on fifteen national food tables. Time Converter handles dates across time zones. I think software people trust with their data should be readable by those people, so I publish the source of nearly everything I make, and I write about the decisions behind it here.

Terje Rutgersen · southern Spain · MIT License

Projects

Principles

Offline first. Your data belongs on your device. My software runs locally, and its essential features keep working without a connection. A feature that needs the network is kept narrow, made optional where possible, and explained before you use it.

Open source. Most of what I make is published under the MIT License, including the server code and configuration behind the Macro Tracker. When a privacy statement says your data stays on your machine, you can check that in the code. If a project almost fits what you need, fork it.

No tracking. Nothing I make adds its own analytics or telemetry, and none of it needs an account. Google Play and the browser extension stores show me the install numbers and crash reports they collect for every listing. Each privacy statement says when data leaves your machine and where it goes. Ordinary visits to this website appear in a security log that is deleted after 14 days.

Free, or one price. Most of it costs nothing. Anything I sell, like Kofte, has a single price and no subscription.

Made to be read. These are hobby projects, and I build them on the assumption that strangers will read the code. That means tests, and a careful look at every dependency before it goes in.

Learning in public. I write about how each project was built, including the parts I got wrong. If you know a better way to do something here, I would like to hear it.

Writing

Wall of Shame

This server has banned SSH brute-force attempts … times in the last two weeks. Bots scan every IP on the internet trying default credentials, and fail2ban catches them automatically. Here's how it works.

The last part of each address is cut before it is written to disk, so the full one never reaches this page and is not in the source either. It stays in the server's own log, where it is needed to actually block anything, and goes no further. An IP address identifies a person under EU law, and I have no legitimate claim to publish one: blocking an attack does not require naming the machine to you. Keeping the first three parts is a compromise. It is here because a wall of banned networks looks cool, and looking cool is worth something. It is just not worth more than the principles the rest of this site argues for, and those apply to whoever is on the other end of these attempts, some of whom are running a box someone else broke into first.