Jupyter Builder

Build tools for JupyterLab extensions — extracted from the core JupyterLab codebase to be maintained and used independently.

Installation

pip install jupyter_builder

CLI

build

Compile the extension JavaScript assets for consumption by a Jupyter app.

jupyter-builder build <path/to/extension>

develop

Install extension assets in development mode (analogous to pip install -e). Uses a symlink by default.

jupyter-builder develop <path/to/extension>

watch

Automatically rebuild development assets when source files change.

jupyter-builder watch <path/to/extension>

For advanced configuration, see the Advanced section for available flags.

jlpm

jupyter-builder ships jlpm, a Jupyter-aware Node.js package manager wrapper:

jlpm install
jlpm build

Advanced

CLI flags

Python API

from jupyter_builder.federated_extensions import (
    build_labextension,
    develop_labextension_py,
    watch_labextension,
)

build_labextension(
    "/path/to/extension",
    development=False,
    source_map=False,
    static_url=None,
    core_version=None,
    core_package_file=None,
)

develop_labextension_py(
    "/path/to/extension",
    overwrite=True,
    symlink=True,
    user=False,
    sys_prefix=True,
)

watch_labextension(
    "/path/to/extension",
    labextensions_path=[...],
    development=True,
    source_map=False,
)

Environment variables

jupyter-builder supports the following environment variables to override network URLs — for example, to point at an internal mirror or a local proxy. A warning is emitted at startup whenever a variable is set.

Example — redirect to a corporate npm mirror:

export JPBLD_NPM_URL=https://npm.internal.example.com
jupyter-builder build /path/to/extension

Core metadata resolution order

When no explicit --core-version is given, jupyter-builder looks for @jupyterlab/core-meta in the extension's node_modules first (no network required). If the package is not found there a warning is printed and the metadata is fetched from the npm registry, falling back to raw GitHub if npm is unreachable.

Uninstall

pip uninstall jupyter_builder

Learn more

• Announcing jupyter-builder: A Standalone Build System for JupyterLab Extensions - the announcement post on the Jupyter Blog, covering the motivation, how compatibility is checked without JupyterLab installed, and how to migrate existing extensions.

Acknowledgments

This package was initially created during GSoC 2024 by @cronan03, mentored by @fcollonval.

Further work on this package was funded by the Jupyter Foundation through its Community Funding program. See the Finish Jupyter Build System Separation funding report for a summary of the work completed.