Michał (Mike) Krassowski's Avatar

Michał (Mike) Krassowski

@krassowski

Maintainer of JupyterLab. DPhil in omics/endometriosis - I miss research. Thinking how to leave the world a better place.

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20.09.2023
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Latest posts by Michał (Mike) Krassowski @krassowski

If you are using AI to open PRs without considering previous reviews and ignoring PR templates, you are not adding value. The point of good first issues was to let humans learn the contribution flow, not for AI to score virtual points.

01.03.2026 12:25 👍 0 🔁 0 💬 0 📌 0
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MUFFANUJ - Overview Probably debugging now ;). MUFFANUJ has 60 repositories available. Follow their code on GitHub.

Should out to github.com/MUFFANUJ for contributing these enhancements!

26.02.2026 12:30 👍 0 🔁 0 💬 0 📌 0
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#JupyterLab 4.6.0a3 enhances the file browser:
- more breadcrumbs are shown to fill space
- name sort order can be changed
- you can 'Open in Terminal' from context menu

Also:
- you can paste code cells without outputs
- before deleting a cell from cell toolbar, you will see a confirmation dialog

26.02.2026 12:30 👍 1 🔁 0 💬 1 📌 0

#JupyterLab 4.5.5 and 4.6.0a3 are out 🚀

v4.5.5 includes bug fixes for:
- table of contents in Markdown
- theme settings in non-English locales
- comms subshell resource management
- slow selection of lines in editor
- scroll anchoring

26.02.2026 12:17 👍 0 🔁 0 💬 0 📌 0

A viewer for Parquet, SQLite, and Avro files in JupyterLab.
Check out our new JupyterLab extension: Arbalister. 🏹
Built upon Apache Datafusion, @jupyter.org , and @arrow.apache.org , it lazily fetches rows so that you can view files larger than memory!

blog.jupyter.org/instantly-vi...

29.01.2026 16:38 👍 15 🔁 7 💬 0 📌 1
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JupyterLab 4.5 and Notebook 7.5 are available! JupyterLab 4.5 has been released! This new minor release of JupyterLab includes 51 new features and enhancements, 81 bug fixes, 44…

JupyterLab 4.5 and Jupyter Notebook 7.5 are here! 🎉

Highlights 🎁

- Enhanced notebook scrolling behavior
- Native audio and video support
- New Terminal search
- Debugger, Notebook and File Browser improvements

Check out the blog post to learn more!

blog.jupyter.org/jupyterlab-4...

24.11.2025 10:10 👍 23 🔁 9 💬 1 📌 1
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Introducing Molview - the ipython/jupyter widget version of nano-protein-viewer🔍:

04.11.2025 02:00 👍 16 🔁 2 💬 1 📌 0

I used to think the friction in community OSS/corporate dynamics comes from a difference in culture between organizations and teams. The more I see the same team flip between amazing and questionable contribution trajectory the more I think this comes down to changing internal direction/incentives.

06.11.2025 12:59 👍 1 🔁 0 💬 0 📌 0

It is hard to express criticism as an established maintainer. The words which I could say as a user now hit differently, even if I mean the same thing.

06.11.2025 12:53 👍 0 🔁 0 💬 0 📌 0

There are two things you should not remove when transitioning to a metapackage: integration tests and documentation. In fact, the transition should double down on these two things as they are critical to ensure the packages integrate well, and that discoverability is preserved.

06.11.2025 12:50 👍 0 🔁 0 💬 0 📌 0

If you will release a new, better, version but without a feature I like, I might come back and contribute it again.
If you release a new broken version, I may not be able to convince stakeholders to engage and come back, the trust in the project will be lost.

06.11.2025 12:48 👍 0 🔁 0 💬 0 📌 0

A mismatch of expectation on what irks #OSS maintainers: I saw folks really worry about removing a feature I contributed due to lack of bandwidth to port it to new version - but this was absolutely fine! I saw them remove tests and ignore my warning against it - and this is what in fact made me sad.

06.11.2025 12:48 👍 0 🔁 0 💬 1 📌 0

I think I tracked it down and Zach contributed this :) Thank you!

06.11.2025 12:38 👍 1 🔁 0 💬 0 📌 0

I'm really curious what is on the contributions slides. Is this a specific repo/subproject? How was it generated?

05.11.2025 20:15 👍 0 🔁 0 💬 1 📌 0

To install from PyPI:

pip install --pre --upgrade jupyterlab==4.5.0rc0

You can also install the RC from conda-forge (anaconda.org/conda-forge/...).

Thank you to Rosio Reyes for compiling the release notes, and thank you to everyone who contributed!

31.10.2025 09:33 👍 0 🔁 0 💬 0 📌 0
New debugger features include a "Paused in Debugger" overlay, better breakpoint and callstack cell annotations, and evaluation in a debugger console.

New debugger features include a "Paused in Debugger" overlay, better breakpoint and callstack cell annotations, and evaluation in a debugger console.

Search in terminal is now integrated with JupyterLab search widget

Search in terminal is now integrated with JupyterLab search widget

Audio and video files can be opened in the main area

Audio and video files can be opened in the main area

New Python file can be created directly from context menu on the file browser.

New Python file can be created directly from context menu on the file browser.

New exciting features are coming to #JupyterLab 4.5.0. Please test the release candidate before & during the JupyterCon (next week!)

Major enhancements around:
- performance and scroll stability
- notebook editing
- table of contents
- debugger
- terminal

jupyterlab.readthedocs.io/en/latest/ge...

31.10.2025 09:32 👍 0 🔁 0 💬 1 📌 0

We've learned that our member communities care a *lot* about cloud cost transparency and reliability, so we're working hard to drill down into user data about costs and usage for community leaders to access.

07.10.2025 17:06 👍 7 🔁 1 💬 0 📌 0
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Go from JupyterLab user to creator 🚀
At JupyterCon 2025, learn to build + publish custom extensions for real-world workflows — guided by experts in JupyterLab development.
🗓️ Nov 3 | San Diego
Details: sched.co/28H2m
Register: events.linuxfoundation.org/jupytercon/r...

07.10.2025 17:09 👍 4 🔁 4 💬 0 📌 1
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Your Ideas, Our Support: Jupyter Community Call For Funding Proposals The Jupyter Executive Council and Jupyter Foundation are pleased to announce a call for proposals for the Jupyter community. Visit the…

🚨 The deadline for Jupyter Community Funding Proposals (blog.jupyter.org/your-ideas-o...) has been extended to October 5th, 2025 ( by one week). We've got a few great-looking proposals in the works (github.com/orgs/jupyter...), so you've all got another 7 days to write!

26.09.2025 20:37 👍 2 🔁 1 💬 0 📌 0
Register for JupyterCon 2025 by October 3 and save $300

Register for JupyterCon 2025 by October 3 and save $300

WHO’S IN? JupyterCon is coming to San Diego Nov. 4-5 with bonus days for Technical Training (Nov. 3) & Community Sprints (Nov. 6).

Save $100 when you register by Oct. 3.

🔸 View the schedule: bit.ly/4gpqkzy

🔸Register: bit.ly/47C1XMK

09.09.2025 17:36 👍 4 🔁 2 💬 0 📌 0
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Jupyter Community Workshops Are Back! The Jupyter Community Building Working Group is pleased to announce that the next call for proposals for Jupyter Community Workshops is now…

A reminder that there are two Call for Proposals out from the Jupyter Foundation!

👉 Jupyter Community Workshops: blog.jupyter.org/jupyter-comm...
👉 Jupyter Community Support funding: blog.jupyter.org/your-ideas-o...

Check them out and share the word!

03.09.2025 18:32 👍 5 🔁 4 💬 0 📌 0
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Jupyter Community Call: September 2025 Hey Jovyans, we want to learn about the great things you’re doing with Jupyter! The Community Building working group is holding an open…

You’re invited to join the next Jupyter Community Call on September 4th, 2025.

Get updates from across the Jupyter ecosystem, hear talks from community members, and get involved. It’s a great way to connect, contribute, and engage!

The Zoom link in our blog post:
blog.jupyter.org/jupyter-comm...

28.08.2025 15:12 👍 11 🔁 4 💬 1 📌 0
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Jupyter Community Workshops Are Back! The Jupyter Community Building Working Group is pleased to announce that the next call for proposals for Jupyter Community Workshops is now…

Jupyter Community Workshops are back! Workshops will be held through February 2026.

The call for proposals is open until September 7th! Learn more and submit your proposal here:

blog.jupyter.org/jupyter-comm...

29.08.2025 01:16 👍 7 🔁 5 💬 0 📌 0
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Your Ideas, Our Support: Jupyter Community Call For Funding Proposals The Jupyter Executive Council and Jupyter Foundation are pleased to announce a call for proposals for the Jupyter community. Visit the…

Have a great idea for Project Jupyter? We want to help you build it! 🚀

The Jupyter Foundation is now accepting funding proposals from all community members. This is your chance to make a direct impact. Learn how to apply! 👇

blog.jupyter.org/your-ideas-o...

28.08.2025 15:22 👍 9 🔁 5 💬 0 📌 1

👋 JupyterLab and Jupyter Notebook users:

What's one thing you'd love to see improved in JupyterLab, Jupyter Notebook, or JupyterLite?

The team is prepping the upcoming 4.5/7.5 releases and wants to tackle some usability issues.

Drop your feedback below, this will help prioritize what gets fixed!👇

19.08.2025 09:43 👍 17 🔁 10 💬 4 📌 0
What's new in JupyterLab 4.4 and Notebook 7.4?
What's new in JupyterLab 4.4 and Notebook 7.4? YouTube video by Jeremy Tuloup

JupyterLab 4.4 and Jupyter Notebook 7.4 will be available very soon.

And they are coming with a couple of nice improvements and bug fixes 🎁

So I just published a new video to do a quick tour of these new features 🎥

www.youtube.com/watch?v=YhYo...

28.03.2025 16:26 👍 7 🔁 3 💬 1 📌 0
The option to change console prompt position is available under the three dots button in the console toolbar, which is the last toolbar button

The option to change console prompt position is available under the three dots button in the console toolbar, which is the last toolbar button

Toggling all the three new settings transforms the console into a single cell

Toggling all the three new settings transforms the console into a single cell

The Import and Export buttons in the Settings Editor are the first two items in the toolbar panel

The Import and Export buttons in the Settings Editor are the first two items in the toolbar panel

The workspace indicator in the open state

The workspace indicator in the open state

JupyterLab 4.4.0b1 and Notebook 7.4.0b1 are available for testing 🎉
- improved code console
- settings import/export
- better real time collaboration
- workspace indicator
- kernel subshells

Please test:

pip install --pre 'jupyterlab>=4.4.0b1'

or

pip install --pre 'notebook>=7.4.0b1'

14.03.2025 09:49 👍 4 🔁 4 💬 0 📌 0
The option to change console prompt position is available under the three dots button in the console toolbar, which is the last toolbar button

The option to change console prompt position is available under the three dots button in the console toolbar, which is the last toolbar button

Toggling all the three new settings transforms the console into a single cell

Toggling all the three new settings transforms the console into a single cell

The Import and Export buttons in the Settings Editor are the first two items in the toolbar panel

The Import and Export buttons in the Settings Editor are the first two items in the toolbar panel

The workspace indicator in the open state

The workspace indicator in the open state

JupyterLab 4.4.0b1 and Notebook 7.4.0b1 are available for testing 🎉
- improved code console
- settings import/export
- better real time collaboration
- workspace indicator
- kernel subshells

Please test:

pip install --pre 'jupyterlab>=4.4.0b1'

or

pip install --pre 'notebook>=7.4.0b1'

14.03.2025 09:49 👍 4 🔁 4 💬 0 📌 0
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Simplifying and speeding up Binder builds with BuildKit The Binder Project allows users to build reproducible, sharable environments for interactive computing. To accomplish this, Binder uses a…

The Binder team recently made environment builds faster and simpler! Here's a post describing how: blog.jupyter.org/simplifying-...

04.03.2025 16:16 👍 15 🔁 3 💬 0 📌 1
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Cloudy With a Chance of Jupyter Install JupyterHub on Azure in 30 Minutes With Nebari

Tired of complex cloud setups? Quansight's Nebari makes JupyterHub deployment a breeze. Scalable, secure, and ready in half an hour. Dive into the details: https://buff.ly/3WPvg7Y #Jupyter #OpenSource

06.02.2025 19:00 👍 2 🔁 1 💬 0 📌 0