Ask HN: Is there any software you only made for your own use but nobody else?

I made bookmarklets to sort multiple retail stores, including my local grocery store website and Amazon by price and price per unit. Amazon price sort is nearly worthless, I assume intentionally. Drives me crazy to grocery shop without price per unit, my bookmarklet also converts units.

I made a browser extension that filters out youtube videos, reddit posts, youtube comments, twitter posts, twitter sidebars, and probably a couple other things based on an extremely long list of keywords of crap i don't want to see - largely political, violent, war related stuff. I think it filters out more than half of posts on /r/all, partially because there's also a long list of popular subreddit blocks on it too.

I made a custom interface for Habitica, a habit-tracking app, to mimic a game from the 90s I really liked.

I made an arduino water gun robot to spray my cats and break up frequent cat fights when i'm all the way on the other side of the apartment.

More random stuff like this.

Wish i could find a job!

does fairly basic word search stuff, and there are lots of more sophisticated programs out there, but none of them run in a linux terminal and that's what i wanted. i have it constantly open in a tab, for various word game related things.

Her parents were super strict and would not allow having a boyfriend, we were caught once so wanted to be few steps ahead of their detection.

Using internet was allowed for her to study. Made the extension such that when you search for something popular click on the largest image in knowledge graph (right side box) 4 times and then do a right click the wikipedia description will become a chat box (to avoid accidental discovery by her sister).

Backend a very simple .txt file and php to insert and maintain only last 5 conversations.

I think I made it over a few days. We used it for a total of 2 times because we couldn’t notify each other when we come online.

Switched to a simple ROT13 encoded sms-ing. With the key changing every day.

A python package to code up reusable TeX expressions, which is used in the said site generator.

A python library for trip planning which let my wife make plans using Google MyMaps and Excels and then my library syncing them up and also shows some visualization in Jupyter Notebooks.