New ask Hacker News story: Ask HN: What are some tools / libraries you built yourself?

Ask HN: What are some tools / libraries you built yourself?
3 by graderjs | 1 comments on Hacker News.
Many times you just want to plug something in. PostgreSQL, Node.JS Express, Java Spring, numpy, Three.js. There's many examples where the already existing solution fits well. Sometimes that's not good enough tho. What are some tools, libraries or services you built, are they open-source and why weren't you satisfied using what already existed?