Profiling web-edit with Python 3.15: flame graphs and source heatmaps

Simon Willison profiled his web-edit app using the new sampling profiler in Python 3.15, directing GPT-6 Astra Extra High in Codex to run the profiler and produce a flame graph and source heatmap demo. The resulting artifacts, a flame graph and a heatmap, are published on GitHub Pages under Willison's research repository. The exercise demonstrates the Python 3.15 profiler's flame graph and source heatmap output on a real PyPI application.

Research: Profiling web-edit with Python 3.15: flame graphs and source heatmaps https://github.com/simonw/research/tree/main/python-3-15-web-edit-profiling readme I put the new Python 3.15 profiler https://simonwillison.net/2026/Oct/12/python-3-15/ a-sampling-profiler through its paces by having GPT-6 Astra Extra High in Codex run it against my new web-edit app https://simonwillison.net/2026/Oct/12/web-edit/ : I need a Python 3.15 flame graph and heatmap demo of the "web-edit" app from PyPI - research first then make me those demos Here's the resulting example flame graph https://simonw.github.io/research/python-3-15-web-edit-profiling/artifacts/flamegraph.html and heatmap https://simonw.github.io/research/python-3-15-web-edit-profiling/artifacts/heatmap/index.html .