diff --git a/.github/workflows/demo-notebook.yml b/.github/workflows/demo-notebook.yml
new file mode 100644
index 0000000..a948f73
--- /dev/null
+++ b/.github/workflows/demo-notebook.yml
@@ -0,0 +1,55 @@
+name: demo notebook
+
+# Builds examples/demo.py (a `# %%` cell file) into examples/demo.ipynb with jupytext, so it can be
+# opened in Colab. On pushes to main the notebook is force-pushed to the orphan `demo` branch, which
+# the README's "Open in Colab" badge points at; on pull requests it is only built, as a check.
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - run: python -m pip install jupytext nbformat
+      - name: Convert the cell files to notebooks
+        run: |
+          set -e
+          for f in examples/*.py; do
+            case "$f" in examples/make_gif.py) continue;; esac
+            jupytext --to ipynb "$f"
+          done
+          ls -la examples/*.ipynb
+      - name: Publish to the demo branch
+        if: github.ref == 'refs/heads/main' && github.event_name != 'pull_request'
+        run: |
+          set -e
+          mkdir -p /tmp/demo/examples
+          cp examples/*.ipynb /tmp/demo/examples/
+          cp README.md LICENSE /tmp/demo/
+          cd /tmp/demo
+          git init -q -b demo
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          cat > README.md <<'EOF'
+          # liveplot demo notebooks
+
+          Generated by CI from `examples/*.py` on `main`; do not edit here.
+          Open in Colab: https://colab.research.google.com/github/ARENA-education/liveplot/blob/demo/examples/demo.ipynb
+          EOF
+          git add -A
+          git commit -q -m "Build demo notebooks from main ${GITHUB_SHA::7}"
+          git remote add origin "https://x-access-token:${GITHUB_TOKEN}@github.com/${GITHUB_REPOSITORY}.git"
+          git push -q --force origin demo
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000..fb57020
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,17 @@
+name: tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  pytest:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+      - run: python -m pip install -e ".[test]" tqdm ipython numpy
+      - run: python -m pytest -q tests
diff --git a/README.md b/README.md
index c26ec53..da92886 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,10 @@
 
 Live training curves in Jupyter, Colab and the VS Code / Cursor interactive window, with a tqdm bar underneath, at (almost) no cost to the training loop.
 
+[![Open in Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/ARENA-education/liveplot/blob/demo/examples/demo.ipynb) [![tests](https://github.com/ARENA-education/liveplot/actions/workflows/tests.yml/badge.svg)](https://github.com/ARENA-education/liveplot/actions/workflows/tests.yml)
+
+Try it in Colab with the badge above: that notebook is [`examples/demo.py`](examples/demo.py), a cell-by-cell tour of the features, which CI converts with jupytext and publishes to the `demo` branch on every push to `main`.
+
 ![training loss every step, eval loss and accuracy every 50 steps, on one panel with two y-axes](docs/demo.gif)
 
 The GIF is cell 2 of [`examples/demo.py`](examples/demo.py), a tour of the features in a cell-separated file: open it in the VS Code / Cursor interactive window and run it cell by cell. That cell trains a tiny numpy classifier, logging the training loss every step and the eval loss and accuracy every 50 steps, laid out as `"loss | eval_loss eval_acc"`. The GIF itself was recorded by the library: `examples/make_gif.py` runs the same loop as a plain script with `record="docs/demo.gif"`.
diff --git a/examples/demo.py b/examples/demo.py
index 740c132..782f541 100644
--- a/examples/demo.py
+++ b/examples/demo.py
@@ -1,12 +1,25 @@
 # %%
 """
 liveplot tour. A cell-separated file: run it cell by cell in the VS Code / Cursor interactive
-window (or paste the cells into a notebook) to watch each plot update live. Running it as a plain
-script also works, it just prints instead of drawing (except the recording cell, which renders).
-
-    pip install git+https://github.com/ARENA-education/liveplot.git
+window, open it in Colab (the README has the link: CI turns this file into a notebook on the
+`demo` branch), or run it as a plain script, which prints instead of drawing (except the
+recording cell, which renders).
 """
 
+# Setup: on Colab, install liveplot; anywhere else it is already installed.
+import subprocess
+import sys
+
+try:
+    import google.colab  # noqa: F401
+
+    IN_COLAB = True
+except ImportError:
+    IN_COLAB = False
+if IN_COLAB:
+    subprocess.run([sys.executable, "-m", "pip", "install", "-q", "git+https://github.com/ARENA-education/liveplot.git"], check=True)
+
+# %%
 import math
 import random
 import time
diff --git a/tests/test_liveplot.py b/tests/test_liveplot.py
index e057b75..e38653c 100644
--- a/tests/test_liveplot.py
+++ b/tests/test_liveplot.py
@@ -181,6 +181,7 @@ def test_interrupt_inside_with_block_is_clean(fake_notebook):
     assert len(p.data["loss"][0]) == n_warmup + 31 and fake_notebook.frames, "final frame drawn, data kept"
 
 
+@pytest.mark.skipif(sys.platform == "win32", reason="os.kill(pid, SIGINT) terminates the process on Windows")
 def test_render_child_ignores_sigint(fake_notebook):
     """Jupyter's interrupt goes to the whole process group; the renderer must shrug it off."""
     p = LivePlot(refresh_seconds=0.1)