ModuleNotFoundError: No module named 'jupyter_server'
Third-person routing text. Fixes notebook failing with No module named jupyter_server: notebook 7 moved the server into the separate jupyter_server package. pip install jupyter_server (or notebook) fixes it. Use when an agent hits this launching notebook 7. Not for classic notebook 6.
TL;DR: notebook 7 needs the separate jupyterserver package and it is missing. Run `pip install jupyterserver` and notebook launches.
The error
ModuleNotFoundError: No module named 'jupyter_server'Fix it
- Install jupyter_server:
pip install jupyter_serverExpected: install completes.
- Verify:
python -c "import jupyter_server; print(jupyter_server.__version__)"Expected: prints the version.
- Launch notebook again. Expected: the server starts instead of the import error.
When this applies
Use this when jupyter notebook (version 7+) fails with the jupyter_server error, common after --no-deps installs.
When it does not apply
If you are on classic notebook 6.x, jupyterserver is not needed; a different problem is at play. If jupyterserver is installed but the error persists, check your environment.
Compatibility
notebook 7.x with jupyter_server 2.x.
Root cause
notebook 7 was rebuilt on top of jupyter_server instead of carrying its own server code. The dependency is declared, but installs that skip dependencies or partial upgrades can leave it out.
Edge cases
Installing plain pip install notebook pulls jupyter_server automatically; the error mostly hits hand-assembled envs. In conda, install notebook from conda-forge to get the matched server.
Maintainer review
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This records the version a maintainer checked. It does not assert that the version is the latest upstream release.