A Python IDE that lives in your browser. No install. No setup. Just code.
PyBolt is a fully browser-based Python IDE built for learners and developers who want to write and run Python anywhere, on any device, with nothing to install. Open the link, start coding.
A full code editor with syntax highlighting, bracket matching, auto-close for (), [], {}, "", '', and a find bar. Your files are saved automatically every 10 seconds, even if you close the tab.
Hit Run or Ctrl+Enter. Python executes right in the browser, powered by Brython. Output appears instantly in the panel below. First run takes a few extra seconds while the runtime warms up; every run after is fast.
Create multiple files and folders, drag files between them, rename, duplicate, and move them with a right-click menu. Closing a tab doesn't delete the file, it stays in the explorer.
As you type, PyBolt suggests completions inline as faded ghost text. Press Tab to accept, Esc to dismiss. It knows Python's keywords, builtins, snippets, and every variable, function, and class you've defined in the current file.
Before your code runs, PyBolt catches common mistakes: wrong-case builtins (Print instead of print), Python 2 syntax, missing colons, bad JSON, and more. Errors are shown clearly before execution even starts.
10 ready-to-use code examples: Hello World, Fibonacci, Classes, Decorators, Generators, Sorting, Dataclasses, Matrix Ops, and more. Click any card to open it in the editor.
A built-in teaching tool that walks through your code line by line, explaining what each line does in plain English.
- The current line highlights in the editor as it executes
- Each step gets a card describing what happened
- Variables update live so you can watch them change
- Switch between Step Output (one card per line) and Full Output (just the printed results)
- Works on mobile too, tap the Explainer button from the PyBolt mobile screen
The Explainer runs its own pure JavaScript interpreter, so it's always fast and works fully offline.
Tweak the IDE from the ⚙ Settings panel:
| Setting | What it does |
|---|---|
| Verifier | Pre-run syntax and mistake checker |
| Autocomplete | Inline ghost-text suggestions |
| Line numbers | Show or hide line numbers |
| Auto Mirror | Auto-close brackets and quotes |
| Auto-save | Save workspace every 10s and on every run |
PyBolt IDE is designed for desktop. If you open it on a phone, you'll see a button to launch Loop Explainer Lite, a mobile-friendly version of the Explainer that fits a small screen, with a collapsible code panel, touch-friendly controls, and a slide-up variables panel.
Any modern browser. Chrome, Firefox, Safari, Edge. No extensions, no plugins, no accounts.
Python support is provided by Brython. The editor is CodeMirror 5.
Supported: variables, loops, conditionals, functions, classes, list/dict/set/tuple, f-strings, slicing, most builtins (len, range, print, input, sorted, enumerate, zip, map, filter, and more), math, random, json, datetime, functools, collections, and other standard library modules.
Not supported: file I/O, networking, numpy, pandas, matplotlib, or any package that requires native code.
- Brython - Python 3 in the browser (MIT License)
- CodeMirror 5 - code editor (MIT License)
- JetBrains Mono - editor font (OFL License)
- Syne - UI font (OFL License)
(c) 2026 supernova0866. All rights reserved.
Source code is visible for learning and reference purposes. Redistribution, modification, or republishing of this project in whole or in part, with or without modification, is not permitted without explicit written permission from the author.
See LICENSE for full terms.