Seapie – a Python debugger where breakpoints drop into a REPL
Author here. I started seapie as a reaction to pdb's command-driven interface in 2019. I wanted a breakpoint to simply mean 'open a Python REPL here', with debugging functionality layered on top instead of replacing the REPL. `seapie.breakpoint()` opens a working `>>>` REPL at the current execution state. Any changes to variables or function definitions persist. Debugger state is exposed via built-ins (e.g. `_magic_`), and stepping/frame control/etc is handled via small `!commands`. I've been using this regularly in my own work for a few years now. Happy to answer questions or hear…
Seapie – a Python debugger where breakpoints drop into a REPL launched on January 12, 2026 with 22 votes, #699 of 14,585 launches that month and more than 90% of that year's launches.
In plain words
Seapie is a Python debugger that opens a standard Python REPL when a breakpoint is triggered, rather than switching to a command-driven interface. It allows developers to inspect and modify variables and define functions directly at the breakpoint, with debugging commands available through small text commands. Built-in objects expose debugger state, and stepping and frame control are handled via these optional commands. It's designed for Python developers who prefer working in an interactive shell while debugging.
written from the facts on this page · September 2026
From the sources
A breakpoint should just mean >>>. Contribute to hirsimaki-markus/seapie development by creating an account on GitHub.
pip install seapie Why seapie? 1. Debugging for humans seapie comes with a user experience focused on discoverability: helpful error messages and built-in help you can reach from anywhere All debuggers let you step. seapie lets Python expressions walk without magic syntax: ”stop when myfunc returns None, and call stack contains myhelper” >>> !walk (_event_ == "return") and (_return_ is None) and ("myhelper" in _callstack_) Checking a variable is print(myvar) changing it is myvar = None . Debugging !commands work in the REPL and inspecting state is just python: > >> _magic_ { '_line_' : 8 , '_source_' : ' return round(total_with_tax, 2)' , '_path_' : '/home/hirsimak/seapie/test/demo.py' ,…from github.com
In the maker’s words, at launch
Author here. I started seapie as a reaction to pdb's command-driven interface in 2019. I wanted a breakpoint to simply mean 'open a Python REPL here', with debugging functionality layered on top instead of replacing the REPL. `seapie.breakpoint()` opens a working `>>>` REPL at the current execution state. Any changes…
Does a similar job
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