A handful of small Python tools I find useful

Built while teaching Python, kept around because I keep reaching for them. Free, no sign-in required.

Formatting helpers

I always forget the directives. These two save me a doc-dive every time.

{:}

f-string format guesser pym.dev/format/

Type the output you want. Get the f-string format spec that produces it.

Date format finder pym.dev/strptime/

Paste a date string. Get the strptime/strftime format that parses it.

Sharing & running code

Paste a snippet, get a link. Or just open a REPL and noodle.

Python Pastebin pym.dev/paste/

Share a runnable Python snippet, with link previews, browser-run, and edit-and-fork.

Python REPL pym.dev/repl/

A full Python REPL in your browser. No install.

Code transformers

Tools that take Python in and give different Python out.

undataclass pym.dev/undataclass/

Convert a @dataclass into the equivalent hand-written class.

Reference

For when you need to look something up.

Python Glossary pym.dev/terms/

An unofficial glossary of Python terminology, in plain English.

Cheat sheets pym.dev/cheat-sheets/

Printable one-page PDFs for built-in functions, pathlib, time complexity, and the REPL. Free with an account.

Since when? pym.dev/since/

Paste Python to see which version added each feature it uses, or look one feature up by name.

pyref.dev pyref.dev

Not mine, but I link to it constantly. Fast search across the official Python docs.

More on the way

Got a tool you wish existed? Let me know.

I keep adding small utilities as I run into the same papercuts over and over. If you have a Python tool you wish lived on the web, send it my way at [email protected].