---
id: web-pdb
version: "2.0.1"
license: MIT License
license_treatment: permissive
maintenance: active
---

# web-pdb — Web interface for Python's built-in PDB debugger

License: permissive · Maintenance: active · Downloads: 82.6K/mo

## What it is and what it does

Web-PDB wraps Python's built-in PDB debugger with a responsive web interface, letting you debug scripts in a browser instead of a terminal. You insert `web_pdb.set_trace()` into your code, and when execution reaches that point, a web UI opens on a configurable port (default 5555) where you can step through code, inspect variables, and run PDB commands. The interface shows the current file with breakpoint markers, local and global variables, and command history.

Since v2.0, Web-PDB has no external dependencies beyond Python's standard library (it uses asyncio for the HTTP server). It works with Python's built-in `breakpoint()` function via the `PYTHONBREAKPOINT` environment variable, and includes a `catch_post_mortem()` context manager for automatic post-mortem debugging on unhandled exceptions. The project is in minimum maintenance mode—bug fixes and Python version compatibility are prioritized, but new features are not actively developed.

Use it for:

- Debug a Python script running on a remote server by opening the web UI from your local browser without SSH terminal access.
- Inspect program state during development using a visual interface with syntax highlighting and variable inspection instead of typing PDB commands.
- Debug multiple processes by running separate `set_trace()` calls on different ports and opening each in its own browser tab.
- Catch and debug unhandled exceptions in a specific code block using `catch_post_mortem()` context manager.
- Use `breakpoint()` in Python 3.7+ code to launch Web-PDB automatically via environment variable without code changes.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Web-PDB provides a web browser interface for Python's built-in PDB debugger, allowing you to debug Python scripts remotely and interactively through a web UI instead of a command-line terminal.

Yes, if you need remote or browser-based debugging of Python scripts. The zero runtime dependencies, recent maintenance, and permissive license make it a low-risk addition. Not suitable if you require active feature development or need to debug in environments where a separate HTTP server thread is problematic (e.g., some serverless runtimes). Single-session browser limitation is a minor gotcha for team debugging.

## Install

pip install web-pdb
uv add web-pdb
poetry add web-pdb

## Installing web-pdb

Before you install: Low friction—a pure-Python wheel with no runtime dependencies beyond the standard library. Maintenance is in minimum mode: the author prioritizes Python version compatibility and critical bug fixes but is not actively developing new features. Last release was recent.

License in practice: MIT License is permissive; you can use, modify, and distribute Web-PDB freely in commercial and private projects with minimal restrictions.

Quickstart:

pip install web-pdb

import web_pdb
web_pdb.set_trace()

# Your code pauses here; open http://localhost:5555 in a browser to debug

Requires Python 3.8 or later. Single browser session recommended—multiple concurrent sessions may display incorrect data.

Verify before relying:

- Whether the asyncio-based HTTP server running in a separate thread creates issues in specific deployment environments (e.g., serverless, containerized).
- Performance or stability impact when debugging long-running or high-concurrency applications.

## Package facts

- License: MIT License (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 82.6K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

remote python debugger web interface, pdb debugger browser ui, python debugging in web browser, remote debugging python scripts, web-based python debugger, pdb with web interface, browser debugger for python, remote-debugging, web-ui, development-tool

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