Please use opencobra/escher for current Escher development. That repository is the preferred home for the latest community-maintained version of Escher and is aligned with the npm package, PyPI package, and website deployments.

Escher is a web-based tool to build, view, share, and embed metabolic maps. The easiest way to use Escher is to browse or build maps on the Escher website.

Visit the documentation to get started with Escher and explore the API.

Check out the developer docs, the Gitter chat room, and the Development Roadmap for information on Escher development. Feel free to submit bugs and feature requests as Issues, or, better yet, Pull Requests.

Follow @zakandrewking for Escher updates.

You can help support Escher by citing our publication when you use Escher or EscherConverter:

Zachary A. King, Andreas Dräger, Ali Ebrahim, Nikolaus Sonnenschein, Nathan E. Lewis, and Bernhard O. Palsson (2015) Escher: A web application for building, sharing, and embedding data-rich visualizations of biological pathways, PLOS Computational Biology 11(8): e1004321. doi:10.1371/journal.pcbi.1004321

Escher was developed at SBRG. Funding was provided by The National Science Foundation Graduate Research Fellowship under Grant no. DGE-1144086, The European Commission as part of a Marie Curie International Outgoing Fellowship within the EU 7th Framework Program for Research and Technological Development (EU project AMBiCon, 332020), and The Novo Nordisk Foundation through The Center for Biosustainability at the Technical University of Denmark (NNF10CC1016517)

pip install escher

Escher uses anywidget to render maps in notebooks, so no separate Jupyter extensions are required. The widget works in JupyterLab 4, Jupyter Notebook 7, VS Code, Cursor, Google Colab, and Marimo.

import escher

# Display a map in a notebook
builder = escher.Builder(map_name='e_coli_core.Core metabolism')
builder

# Overlay reaction flux data
builder.reaction_data = {'PFK': 1.5, 'PYK': 0.8}

# React to map clicks in Python
import ipywidgets as widgets

out = widgets.Output()
display(out)

def on_reaction_click(change):
    with out:
        print(change['new']['bigg_id'])

builder.observe(
    on_reaction_click,
    names='selected_reaction_event',
)

To overlay flux from a COBRApy model:

import cobra
import escher

model = cobra.io.load_model('textbook')
solution = model.optimize()

builder = escher.Builder(
    map_name='e_coli_core.Core metabolism',
    model=model,
    reaction_data=solution.fluxes.to_dict(),
)
builder

The COBRA model is synced into the widget so build mode can add reactions directly from it. FBA itself runs in Python.

Map names must match the names in the Escher map index. To inspect available maps:

escher.list_available_maps()

The build toolchain uses Vite for the JavaScript bundles, Vitest for JS tests, and uv for the Python package.

• Node.js 18+
• Yarn (classic / v1) — yarn.lock is checked in
• Python 3.8+
• uv
• Pandoc for building the docs notebooks

yarn install          # install dependencies
yarn build            # produce dist/escher.js, dist/escher.min.js,
                      # dist/escher-widget.js, and dist/escher.css
yarn test             # run JS tests
yarn copy             # copy build artifacts to py/escher/static/

For live development:

yarn watch            # rebuild on source changes
yarn start            # start the Vite dev server

The JavaScript build artifacts must be present in py/escher/static/ before installing the Python package from source. After running yarn build && yarn copy:

cd py
uv sync --extra dev   # install package and dev dependencies
uv run pytest         # run Python tests

For notebook use, run Jupyter from the Python package directory so uv uses the Escher project environment:

cd py
uv run --with jupyter jupyter lab

For local development, first rebuild and copy the JavaScript assets into the Python package, then run Jupyter with the local package installed in editable mode:

yarn build && yarn copy
cd py
uv run --with-editable . --with jupyter jupyter lab

That Jupyter session imports Escher from the local py/escher/ source tree, so Python changes are picked up from the checkout. When changing JavaScript or CSS, rerun yarn build && yarn copy before restarting or refreshing the notebook widget.

yarn install && yarn build && yarn copy
cd py && uv sync --extra dev && uv run pytest

The docs are built with Sphinx and nbsphinx. The Python docs dependencies are declared in py/pyproject.toml under the docs extra, and docs/build_docs will run Sphinx through uv when uv is available.

Pandoc must also be installed separately because nbsphinx uses it to convert notebooks. On macOS:

brew install pandoc

cd docs
./build_docs          # installs/uses py[docs] through uv, then builds HTML
cd _build/html
python3 -m http.server