Ask HN: What kind of online tools are you using, missing or can be improved?

When we speak of online tools, one can think of converters, calculators or even auxiliary functionalities.

What kind of tools are you currently using, missing or think can be improved?

Some examples:

- timestamp to date converter (e.g. https://magictools.dev)

- input tools (e.g. https://www.google.com/inputtools/)

- text comparison tools (e.g. https://text-compare.com/)