Saving and sharing

Notebooks in the JupyterLab file browser live in your browser’s storage. Saving a notebook to Oceanum.io puts it in your account instead, where it follows you between machines and can be shared.

Three commands do this work. They are on the File menu, and in the command palette under the Oceanum category:

Command	What it does
Open from Oceanum…	Open a notebook saved on Oceanum.io
Save to Oceanum	Save the current notebook to Oceanum.io
Share on Oceanum…	Share the current notebook through Oceanum.io

All three need you to be signed in, and each offers you sign-in if you are not.

Saving a notebook

File → Save to Oceanum stores the notebook that is open. Its stored name is the file name without the .ipynb extension, so rename the file first if you want the saved copy to read differently.

The first save creates a new record and writes its identifier into the notebook’s metadata; later saves update that same record. If you cannot write to the linked record — it was shared with you read-only, for example, or it was created under another organisation — you are offered Save as a new copy instead.

A saved notebook has to fit in 30 MiB, the limit the extension applies below the service’s own 32 MiB ceiling. A notebook over that size is saved without its cell outputs, and the notification says so. If it is still too large without outputs, the save is refused.

Opening a saved notebook

File → Open from Oceanum… lists what you can open, in two groups:

• My notebooks — notebooks you created.

• Shared with me — notebooks shared with you, and public ones.

Select one and choose Open. The notebook is written into an Oceanum folder in the file browser and opened from there, so you always edit a copy in your browser; Save to Oceanum sends your changes back to the record it came from.

Cells open untrusted, so JupyterLab does not render stored HTML or Markdown output until you run them yourself. This is deliberate: the browser has no notebook signatures to check, and anyone with write access to a shared notebook can change what it contains.

Sharing a notebook

File → Share on Oceanum… shares the notebook that is open. It has to be saved to Oceanum.io first; if it is not, the dialog offers to save it.

The dialog shows the link that opens the notebook, with a Copy link button, and asks who to share it with:

• A specific person — enter the email address they sign in to Oceanum.io with, and choose can view or can edit.

• Everyone with the link — make the notebook public. Read the warning below first.

• Stop sharing with everyone — withdraw public access. People you shared with individually keep theirs.

Only the owner can share a notebook. If you created it while acting as a different organisation, switch to that organisation and try again.

A share link looks like this:

https://notebook.oceanum.io/lab/index.html?oceanum-notebook=<id>

Opening it loads the notebook into the recipient’s own browser. Someone who cannot read it yet is offered sign-in, and the notebook opens once they have signed in.

Sharing with everyone

The dialog warns you first, and it is worth reading. Anyone with the link can read the notebook, including people without an Oceanum account, and access cannot be limited to your organisation. The notebook’s name also becomes visible to anyone who lists Oceanum notebooks.

Your email address is not exposed by sharing. Oceanum.io returns a record’s creator only to the person who created it, so others see a public notebook without learning who saved it. The dialog’s current wording also mentions your email address; that part is out of date.

Treat a notebook shared this way as published. The link needs no account to open, and public access cannot be narrowed to your organisation. Use Stop sharing with everyone to take it back.

Before you share

• Never share a notebook that contains a credential. A Datamesh token typed into a cell is stored with the notebook. Remove it and sign in instead.

• Outputs are stored too, unless they had to be dropped for size. Anything visible in an output is visible to everyone the notebook is shared with.

• There is no live co-editing. Each save replaces the stored notebook, so when two people with write access save the same notebook, the last save wins.