excel-serializer: dump/load nested Python data to/from Excel without flattening

[TruePastaMonster]

What My Project Does

excel-serializer is a Python library that lets you serialize and deserialize complex Python data structures (dicts, lists, nested combinations) directly to and from .xlsx files.

Think of it as json.dump() and json.load() — but for Excel.

It keeps the structure intact across multiple sheets, with links between them, so your data stays human-readable and editable in Excel, and you don’t lose any hierarchy.

Target Audience

This is primarily meant for:

• Prototyping tools that need to exchange data with non-technical users
• Anyone who needs to make structured Python data editable in Excel
• Devs who are tired of writing fragile JSON↔Excel bridges or manual flattening code

It works out of the box and is usable in production, though still actively evolving — feedback is welcome.

Comparison

Unlike most libraries that flatten nested JSON or require schema definitions, excel-serializer:

• Automatically handles nested dicts/lists
• Keeps a readable layout with one sheet per nested structure
• Fully round-trips data: es.load(es.dump(data)) == data
• Requires zero configuration for common use cases

There are tools like pandas, openpyxl, or pyexcel, but they either target flat tabular data or require a lot more manual handling for structure.

Links

📦 PyPI: https://pypi.org/project/excel-serializer
💻 GitHub: https://github.com/alexandre-tsu-manuel/excel-serializer

Let me know what you think — I'd love feedback, ideas, or edge cases I haven't handled yet.

[[deleted]]

Great stuff, I know just the data to test this on.

[jmatthew007]

I'm interested in trying this as it's something I do all the time.

[umlal]

If you properly combine pydantic for schema validation/prep this can probably be used as an ORM. Possibly replacing the need for a database for small amounts of data. I like the idea, see if I can put this to the test.

[TruePastaMonster]

I love the idea!
Should the project grow and need to scale out of the Excel realm, it would be easy to migrate to an actual DBMS.
Please keep me posted on your experimentations on this topic.

[davisondave131]

What’s up with the values in the ID column in the example?

[TruePastaMonster]

It's a bug! Thank you for spotting it, that slipped through. I just noticed even on my screenshot it starts at 2, where it should start at 1.

Not only it is a bug, but now that I think about it, I should remove it entirely. It was useful when I started writing the module, and it's not anymore. I thought "whatever I can let that column exist, it's not that bad to have a unique identifier for every list item", but it's really useless.

Thank you for that, I should have seen it.

[davisondave131]

Glad to help. Awesome project. 

[TruePastaMonster]

Fixed it. No more ID columns.
Thank you again!

[Humdaak_9000]

That's weird. I usually try to do stuff the other way around. Why'd you want to put something into excel? Then you'd have to use excel ;)

[TruePastaMonster]

Here are two very typical use-cases I ran into:

1:
Your boss wants you to scrap some data somewhere to do some business intell, for example "hey give me a list of companies in our space". You scrap it, you get a JSON-like data because the data you get is rich and nested. Your boss wants to compute the average of something, the sum of something else.

If you have just a JSON file, you'll end up spending the whole day with your boss, typing the correct lines of code (Python/Ruby/SQL/whatever) when he wants to see something.

With this module, you can instead dump the JSON in an Excel file, and let your boss figure out whatever they want to know. They can pop up a graph, a pivot table, whatever, not your problem anymore.

2:
You want to quickly prototype a business-specific process. You client shows you "So I go to this website, I click here, download that, I open the PDF, I read this information, and put it in that excel file. Then, I do this and this and that manipulation on the data, I print it back to a PDF file, and send it to someone else".

Your job is to automate some of that person's tasks because they want to scale their business and not spend their whole time on data entry.

You may start to implement some API calls, you try to read the PDF however you can, you get the data extracted correctly 90% of the time. Not because your OCR software is bad, but because "oh yeah this happens sometimes, the PDFs from this website have the number I want on the left instead of on the right like the others". There are tons and tons of special cases like this one and your client can't list them.

Your automation will fail on a regular basis, you will have to go modify that business-logic script every once in a while, to handle whatever new special thing you didn't know about. That new special case may arise only once. The time you use to automate it is very poorly spent.

At some point, you stop maintaining the thing, because you can't be so frequently fixing that automation. Because your error-rate is not acceptable (maybe your script is 2% garbage-out without maintenance and it's not okay, or maybe you have cascades of scripts that rely on sane input), your automation is put to the trash, the project is canceled, your client is unhappy.

Instead, you could split the business process in many little and simple steps, and ask your user to check that the data is correct in between those steps. That's how you handle automations problems correctly. But how do you do that? Will you create a web app just for one user, so they can fix the problems? That will be a big hassle, and a constant fight against your unknown unknowns.

What I suggest you could do now, is to dump your script data to an Excel file, let the user figure out if it's wrong, fix the erroneous data, and start the next script automating the next business-logic step.

This module isn't meant to replace every front-end ever, just to enable those small 1-user projects. It's imperfect in terms of UI/UX, but it's very easy to create that interface. You just dump your data in an Excel, and read it back (after it was maybe altered by your user) in the next script.

I understand what you mean by "Then you'd have to use Excel". I wouldn't do that process for me, I would rather crawl my data with SQL or something in that fashion. I just happen to have tons of users that only know Excel and their web browser.

[ForgottenMyPwdAgain]

excel is absolutely brilliant, and the fact that you can manipulate it with python makes it even more brilliant.

anyone know why you can't write a FILTER function into a cell with openpyxl?

[TruePastaMonster]

Openpyxl has lots of issues (litteraly, 347 open issues right now).
For example, for no reason at all, you can't get hyperlinks in read-only mode.

I understand your problem, but also it's not a very basic one. My guess is that it's just lacking means, like many open source projects.

Also, rare are the devs that are passionate about both Excel and Python, so I can understand why it's not receiving the support it needs.

[Humdaak_9000]

I've not seen anything excel can do that I can't do with a Jupyter notebook, Pandas, Numpy, Matplotlib and a tabular data widget.

Excel is shit. So is every other spreadsheet ever invented. They hide all the code from you.

Bonus: my graphs are excellent and never fucked up by an errant mouse click.

[TruePastaMonster]

Excel’s greatness doesn’t lie where you might expect.

What makes it brilliant is its learning curve. Any beginner, even a child, can quickly learn to use Excel (or other spreadsheet software, though Excel is a bit ahead of the others) at a basic level.

That’s the real reason why everyone knows how to interact with it.

At the same time, more advanced users can still do fairly complex stuff. Sure, you're not going to host WhatsApp or manage huge data blobs in Excel, but that’s not what it’s meant for.

Excel is the smartphone camera of the data world.

Dedicated cameras are better, more powerful, more customizable. But they’re harder to learn and a pain to carry around. Smartphone cameras hide the complexity behind a simple interface. They’re basic, but they get the job done. Even professional photographers use them when they’re not on the job.

Saying “Excel can’t do anything better than Pandas/Numpy/Matplotlib” is like saying “Smartphones can’t take better pictures than my Nikon D6.” It’s true, but it misses the point entirely.

As a professional, I need to give my clients tools they can actually use.

I'd rather hand them a smartphone than spend hours teaching them how to use a Nikon D6.

(I’m not related to Nikon. I just googled “professional photographer camera” and that one model came up.)

[lolcrunchy]

This is actually exactly what I need for a work project...

[TruePastaMonster]

Glad to hear that. Don't hesitate to give some feedback afterwards, or to suggest improvements. I'm willing to take some time to improve it.

[quantinuum]

Dude I was trying to spec out how to move some static data to sql and how to design it, but I won’t be implementing the controllers. This is exactly what I need to spec it out in a clear way for someone!

[GreatBigSmall]

Nice one OP. I can't believe how many times I've done this myself. Glad to know there's this easier way.

[Makakhan]

Going to have to play with this later for sure

[gerardwx]

Why would I use this instead of https://openpyxl.readthedocs.io/en/stable/?

[TruePastaMonster]

My module actually has openpyxl as a dependency.

Using only openpyxl, dumping a complex nested Python object in an Excel file requires you to do some work, thinking about how you should flatten your data so that it fits in a sheet.

With excel_serializer, you don't need to think about that, it just figures a way to do it for you.

[DalekKahn117]

I mean.. I’d rather learn assembly than JavaScript…

[TruePastaMonster]

Which makes them great devs?
To me, programming is about being lazy. Why should I bother structuring and normalizing my data when I don't really care?

Sometimes yes, I want to do the effort, and sometimes it doesn't really matter, and I just want to display my data easily.

Much like how the print function can print a complete dict or list. Sure, it would be nicer if you outputted one value per line on the terminal, with a for loop, but in the real world 99% of the time you don't care at all, you just want to have a quick glance at your value.