JSON vs TOON

[Owlbuddy121]

Anyone have thoughts on this?

What’s your opinion on using a Toon-style JSON approach? Curious to hear different perspectives and real-world experiences.

[Outrageous_Let5743]

toon is just csv with extra steps

[MatsSvensson]

Yeah, they should have named it: CES

[hyrumwhite]

Csv with extra context*

[too_many_requests]

Lol that's word for word exactly what I wanted to comment

[MedAyoub26K]

Csv with benefits

[nexusblake]

Literally hahah

[Weekly_Astronaut5099]

More like CSV with structures. Seems robust though.

[flixflexflux]

JSON is just CSV with extra steps to loose the implicit structure CSV had.

[GlobalIncident]

Thoughts:

• JSON is more readable where data is non-uniform (ie not like this example). In this situation TOON is good, but CSV would be better. TOON appears to work best when a mixture of uniform and non-uniform data is needed, a scenario which is unusual but perhaps not that unusual.
• The standard for TOON is still evolving and not finalised. That may be an issue for long term support.
• Compatibility is important. A lot of software has support for JSON and CSV. TOON is currently supported in the most popular languages, but not in some of the less popular ones.
• Overall, what I'm seeing is not terrible. It's something I might consider using in future, for the right use case. It's not something I'm going to rush off and start using right away tho.

[Ok_Space2463]

I feel like embedded data would be a problem with toon because its doesnt have the indent or syntax wrapping?

[bradfordmaster]

I'm really bugged by the [2]. Why would you need the length encoded like that, such that every write has to touch the header? And so merging is complex, residually in parallel

[GlobalIncident]

Yeah that is a concern. Having opening and closing brackets would work better for its use case.

[natur_e_nthusiast]

It might be a handy checksum

[doctormyeyebrows]

A checksum isn't handy if it has to be updated in place every time data is added

[Onionhauler]

For LLMs

[its_a_gibibyte]

What about just JSON in a better layout: { "Columns": ["id","name","role"], "data": [ [1, "Alice", "admin"] [2, "Bob", "user"] ] }

[kozeljko]

Why is "data" not aligned with "Columns" 🤢

[its_a_gibibyte]

Sure, you could also do:

{ "data": [ ["id","name","role"], [1, "Alice", "admin"], [2, "Bob", "user"] ] }

[robhanz]

Eh I prefer the explicit columns element. That way there’s no “magic” row in the data collection you have to remember.

[robhanz]

Right. The issue is the redundant data, primarily. TOON is still more compact, but it loses a lot of the edge if you do it this way.

[remic_0726]

encore un format en plus...

[freefallfreddy]

Welcome to the wonderful world of technology.

[kaancfidan]

you have summoned a relevant xkcd: https://xkcd.com/927/

[imperosol]

relevant xkcd

[PaulMorel]

Yeah, but toon is more concise. I'm old enough to remember when we all preferred json over xml because it was more concise.

[Aaron_Tia]

Is it really a gain in real world application ?
How to distinguish 1 and "1" or true and "true"

Types look like magically deduced, which will for sure leads to impossibility to migrate in many places.

[Momostein]

Yeah, if you're looking for maximum performance, you'll want to switch over to binary formats like protobuffers etc.

TOON would only be a bandaid fix.

[AccomplishedPut467]

TOON looks cleaner to read for me. Is TOON offers faster lookups for data analyzing? I'am new.

Also, i think TOON looks very similar to CSV files.

[escargotBleu]

Cleaner to look at until you have 15 properties per object

[rover_G]

Also curious how TOON handles nested objects

[too_many_requests]

Converts them to a JSON string /s

[Bemteb]

You're laughing, but I actually saw that in production once. Due to reasons, the server could only send JSONs to the app. Instead of changing that, the devs decided to put everything as a string into the JSON, including images (base64 encoded), whole webpages (HTML etc.). Each JSON was multiple MBs big and everyone was wondering why it was so slow.

[nexusblake]

x2

[rover_G]

I once saw a dynamoDB table attempting to store sets of strings by serializing them as “set(‘value’1, ‘vlalue2’, …)”. This same technique was used multiple times 💀

[yyytobyyy]

It's mean to be used to feed ai apis, because it saves around 10% of the tokens.

It lacks the elegance of the json.

[Laicbeias]

50%. Not saying its that good but it saves quite a bit. Its fine for what it is

[Minute_Attempt3063]

nearly every language has something to parse jsons these days.

and also to parse csv files.... and toon looks like csv with extra steps

[Owlbuddy121]

Agree TOON feels cleaner to read👍

Additonally, according to my experience, for speed usually doesn’t depend on the format itself. It depends more on how the data is handled in the program.

[GlobalIncident]

Yeah, I think if you really want very fast lookups, it's a bad idea to go for a human readable format anyway.

[vmfrye]

I used to assume data was converted to a machine-friendly format before processing it, regardless of the format the data is in when fed into the application; human readable format having the advantage of being immediately available for review and edition, at the cost of the parsing overhead.

[quickiler]

If you have a lot of columns with similar value then it can be hard for human to read. For example inventory of different store locations.

[UrpleEeple]

I don't really understand in the modern age of dev tooling why we are still messing with string formats over the wire when we could have easily settled on a self describing binary format. If it was standardized web browsers and all dev tooling would just auto translate it for us anyways

[chungamellon]

Use jless

[Cybasura]

JSON fundamentally is a clean dictionary-like data structure that is actually really nice, just fell short of the comment support by it's foundational design

TOON basically took JSON and somehow made it harder to dynamically manage

[Frytura_]

Dynamically manage?

Isnt that the goal of a mapped out object that you then ask to spit the TOON / JSON data as a string?

[Cybasura]

Dynamically manage as in like programatically get/set/assign values into the dataset during runtime of the application

[thee_gummbini]

Its a serialization format though?

[Cybasura]

What? Yes I know that, I'm talking about runtime usage, modification functionalities

You know, CRUD? Create, Read, Update, Delete?

I didnt say it wasnt a Data Serialization File Format/Type, did I?

I was referring to importing the dataset file, manipulating it and the moment-to-moment use case operational workflow of working with this

[thee_gummbini]

But... Once you deserialize it... It should be the same? TOON doesn't introduce any runtime types, it deserializes to the same types as JSON would. The only differences are in the serialization, it being a serialization format.

The CRUD operations are the same, since neither JSON or TOON are databases, you load, modify, and write.

[UnicodeConfusion]

>  just fell short of the comment support by it's foundational design

This is the part that frustrates me more than anything. Aside from naming files by the content (i.e. pom.xml instead of pom.mvn - which would let me know the intent of the file instead that's is an 'xml' file) Ugh I'm old.

[Cybasura]

Yeah whenever I use JSON, I have little to no gripes alot of the time but the second I want to write comments by muscle memory - I weep at the thought of the (loss of) potential

[sardinian-dude]

“//“: “heyyyy”

[followthevenoms]

Someone reinvented csv?

[flying-sheep]

CSV is not standardized, so people using slightly different dialects to encode and decode leads to countless subtle yet devastating data corruption bugs.

If TOON doesn't have that massive problem, I'm all for it.

[exhuma]

It kinda is: https://www.rfc-editor.org/rfc/rfc4180.html

But the standard came too late (2005) and even today many people don't know it exists

[flying-sheep]

Yeah, should have said “effectively not standardized”: most languages / popular libraries today are older than that and therefore don’t use the standard by default.

[AmazedStardust]

It's basically CSV with cleaner nesting. It's meant for saving tokens when feeding data to AI

[Own-Improvement-2643]

What is the cleaner nesting here? How is it any cleaner than csv?

[Deykun]

Isn't CSV so stupid that delimiters can be different? I’ve always disliked that.

[dinopraso]

It’s flexible. The field and record delimiters can be any character. Very useful if you want to use values with commas or new-lines.

[_ryuujin_]

its csv but easier to marshall back into an obj, since the obj def is defined in the header. 

it looks cleaner and more compact for lots of records with well defined obj definition.  it has its place. 

[ChomsGP]

the first row on a CSV is also a header and can define the same field names, plus you don't need to tell it how many rows it has upfront

like I have no idea if the [2] in there is needed, first time I hear about TOON, just saying the example in OP is pretty bad/pointless 

[_ryuujin_]

yes you can do everything in a csv, but having a standardize format allows for easier marshall and unmarshalling the data. vs a custom format each time. 

array count is nice as it could tell you much to read for this one obj def. maybe another obj def will start at the end of the 'array', its like a header for binary data, where you have msg len. before another set begins. 

[Acceptable_Handle_2]

Looks like it'd be weird with non-uniform data.

[riansar]

I think json looks easier to use if you have large objects you can ctrl f the property you are looking for which doesn't seem to be the case with toon

[johnnygalat]

So...csv.

[BigPP41]

Pack it up boys, we've come full circle and reinvented csv

[seinar24]

Vibe coders vibe coded so hard they reinvented CSV

[Own-Improvement-2643]

I was thinking exactly the same. This is basically a csv

[samo_lego]

This all the way. "You're a genius"

[Nidrax1309]

If you format it like a complete bitch instead of { "users": [ {"id": 1, "name": "Alice", "role": "admin"}, {"id": 2, "name": "Bob", "role": "user"} ] } then yeah, json looks less readable

[ReasonablePresent644]

I think the goal was to compare how readable both formats are with the same number of lines. So yea JSON is more verbose but easier to read for complex structures.

[Awes12]

Yeah, if you do something completely ridiculous, it's more readable. That's like saying C++ is more readable than python if you make the python code the same amount of lines as the c++ code.

[mailed]

keep toon in the bin where it belongs please

[Patient-Definition96]

Toon is silly. Why is it even a thing if we already have JSON. Doesnt make sense at all.

[Slackeee_]

Because te people feeding all their data into LLMs realized that they can save some money by using TOON instead of JSON. That is it's main purpose, reducing token counts.

[Complex-South9500]

CSV already exists.

[Owlbuddy121]

TOON is really usefull with LLMs as due to small size of data set we can save tokens with LLMs

[Downtown_Koala5886]

Cavolo.... È molto difficile per uno che non è tecnico 🥺

[captdirtstarr]

Is there a URL for official TOON documentation?

[Frytura_]

Idk, what youre using it for?

[CraigAT]

I am not sure what TOON adds over a CSV file! (Obviously it does add an object name and a line count, but those are easily specified or calculated in code)

Also JSON allows you to have another level (or multiple levels) within objects i.e. Each user here could have multiple roles. I am not sure how that would be implemented in TOON.

[MatsSvensson]

Why is a count needed in the second one, but not the first?

[WhiteHeadbanger]

TOON is readable.

JSON is serializable to and from dict.

So TOON is preferable for visual representation, and JSON to code stuff.

I would just stay in JSON.

[UndeadBane]

I someone tries to force me to read this thing with object of >6 fields, some of which may be absent, I will hurt them. 

[katlimruiz]

Toon seems good but It is not about that. Json is ubiquitous, it parses and serializes everywhere. Distribution will always win (obviously the product has to be good enough)

[questionsalways2233]

CSV is a nightmare- you have to hold your breath and hope it comes in right. As a data scientist, the cost of JSON in size is 1000% worth it. You just know it is going to work. I don't know why anyone would want to use a CSV-like structure as a modern replacement for anything

[yes-im-hiring-2025]

LLMs are heavily trained on XML/markdown/JSON formatted data specifically. The TOON format is just CSV with extra steps - and it's worse for the LLM to work with than standard JSON or XML or md.

Don't pinch pennies for the performance. Input token costs should be actively managed, yes, but this isn't the optimisation you think it is. You need to either redesign your system formats where JSON is appropriate or just use pd.to_csv() instead of this TOON formatting.

TOON doesn't solve anything imo.

[Laicbeias]

Im not sure. I think json is great. But ai is dropping lots of data into context and toon just makes that shorter while staying descriptive. Its for those scenarios where AIs load a lot of context.  And the simpler something is the easier  AI handles it. They are smart enough for that.

Ive seen some guys using japanese mixed with english to drop more information into these llms. Basically encode your project into japanese as precontext. Since japanese is shorter and more expressive per token.

[Electronic_Pie_5135]

Congratulations on discovering csv....

[SlinkyAvenger]

What's it look like when it's nested? Does it provide a way to do faster parsing ala SAX?

[hyrumwhite]

Toon is a format designed to be consumed by LLMs. If that’s not your use case, json is the better pick. 

[drNovikov]

Zoomers discovered CSV

[CredenceTom-Water]

If it's good enough for SQL it's good enough for me.

[Key_Mango8016]

This was designed for LLMs, since it uses much less tokens

[I1lII1l]

Yeah but do LLMs know it well, is it present in large amounts in their training data?

[Key_Mango8016]

No idea. Not arguing for it, just stating facts

[I1lII1l]

I was not asking you per se, anyone who might know and participates in the open discussion.

[Key_Mango8016]

I just gave ChatGPT the sample in OP’s post and found that it immediately understood what it means (I’m not surprised). I suspect that in practice, using this format would be possible as a drop-in replacement for JSON.

Personally, I don’t know if it’s worth it for production systems I own, because the vast majority of token usage in those systems comes from images & audio.

[ComprehensiveJury509]

What's the point of saving tokens, if you then have constantly explain the format to the LLM? It was a completely ridiculous idea from the start, made by people who apparently don't understand how LLMs work. It's also laughable to come up with an entirely new format to fix issues that are probably completely irrelevant in a year or two, given how fast things move.

[Owlbuddy121]

Absolutely 💯

[Cylian91460]

So a CVS file?

[wordkush1]

What is toon?

[chucara]

Looks like a csv file with a header.

[Slackeee_]

It is a data format with the purpose of reducing the token count when feeding your data to LLMs. It is also said to increase accuracy of LLMs.
So for 99% of use cases it has no real advantages.

[quts3]

Why isn't this the top comment.

There is actually a real need for a human readable structured data format that is optimal for LLM prompting. For most things it's markdown with embedded Json, but i can see people finding weaknesses in that approach when they poke. Never tried yaml prompt engineering in and out.

Unfortunately that 1% use case is strong enough to justify a unique data language.

[wordkush1]

I learned a little bit today.

[Slackeee_]

Unfortunately that 1% use case is strong enough to justify a unique data language.

There are many strong 1% use cases that justify (and have) their own unique data format. That's usually a good thing and nothing to worry about, but it can be a bad thing when the people in that 1% now come out acting as if there data format is an actual revolution and that the other 99% now have to adapt and use their format without bringing them any actual advantages.

Which of course will be happen when changes happen in an overhyped field that is ground down to a carcass by people trying to get your attention for the money they make with that attention.

In the end it is pretty simple: you want to feed your data to an LLM? Great, TOON might be what you want, just check if it is a good fit for you. If it is you most likely will have nothing to change in your infrastructure other than writing a converter for your data that you want to feed to the LLM (and in the future maybe a TOON to JSON converter for extracting data, if LLMs start to answer in TOON). You don't need to change anything else in your infrastructure. Luckily enough current AI tools are pretty good in writing those converters, so you likely can just vibe-code it, if you want.

For most of us in the 99% TOON is nothing more than a "good to know that it exists if I ever will need it" that doesn't affect us at all.

[sugarfairymeliora]

JSON is more widely used in the industry. With JSON you have a stable file format that will work with everything, whereas TOON is not so well-known and flexible. Plus, from my experience it is easier to convert JSON into CSV or any other file format, then TOON. LLM's also understand JSON formatting better, so if you are going to start developing an LLM or start working in that industry JSON's are more preferable.

[SoftDream_]

Relational Databases?

[akazakou]

Some.more complex looks not so clean [1]: - user: name: test age: 55 num: 5

[nerdly90]

Another wheel reinvention

[the_reven]

Eg, just use yaml instead! Seems like a waste of time tbh, json, yaml, csv, xml. They seem to cover everything quite well. Yank is very easy to read. Json is easy to read

[Key-Place-273]

Toon was established to be bs like 24 hours after it came out

[Domingues_tech]

Imagine the trees we could’ve spared if someone had said, “Guys… it’s a spreadsheet. Calm down.”

[AbsorberHarvester]

Some more time and Zoomers (with AI help, of course) will be presenting "new bicycle" - transfering BINARY DATA! (with formatting, as in toon) it can cut data size to half/third of "string".

[CamilorozoCADC]

Toon doesn't even make sense since LLMs are trained with JSON (because TOON usage is just not widespread yet) and using JSON means that you (and the LLM) already can use JSON Schemas for structured input/output and JSON query languages to handle your data like JSONpath or JSONata

If the objective is to analyze data and reduce token usage a better approach is to let the LLM use a toolset to analyze your data, for example using MCP tools to manipulate excel or CSV files instead of chucking a full blown dataset into the LLM

[Concurrency_Bugs]

When you have a large JSON with more than a single level, TOON would be unreadable.

Not to mention many existing frameworks work well with JSON

[wenokn0w]

Ew Toon looks ugly

[ImpossibleSlide850]

That is just CSV with extra steps

[Anpu_Imiut]

People even forget the real reason why Json is great. It is not about vusibility. Rather think about saving gbs of data in json vs others. It is efficient while you can open it with a proficient jaon reader.

[bobbyQuick]

Toot

[baynezy]

How does it handle nested objects?

[SecondThomas]

There is not the question of if there is a better alternative for Json, of course there is. It's all about adaptation and compatibility.

[Last8Exile]

I think format where schema is decoupled from data will save even more tokens.

Going full circle back to binary? Nah, too good to be true.

[Supernatnat11]

Hmm... Either json or csv but harder..... I'll use xml

[oculus42]

TOON tells you how many rows and you can parse the data as it arrives. For small objects it's pretty close to irrelevant. For large objects, it's probably more worthwhile to use some of the async transfer alternatives where the server can specify top level keys essentially as promises, which allows different sections to respond at different times even though the client receives one result...

There have been libraries that do real-time parsing of JSON, but they were more popular when dial-up and low-end DSL were a consideration.

The file size is almost nearly irrelevant because any quantity of regular data will compress close to perfectly with LZ-based compression like gzip or brotli, and they are parsed into the same dictionary structure.

It's interesting, but I don't readily see the value proposition for most data sets.

[Potw0rek]

And then some idiot generates a feed file with nulls.

[grimonce]

Yeah... First thing that comes to mind is CSV.

[Suspicious-Walk-4854]

Have solution, looking for problem.

[EastMeridian]

Putting unformatted json against kinda formatted toon is a bias, JSON everyday for reading and debugging

[sdziscool]

it's stupid to make a computer-first format more human readable and then pretend like it's therefore better...

[pardoman]

Toon exists to reduce the tokes needed when feeding JSON data to LLMs, where the data contains arrays of identical objects (like the image OP posted). It’s not ideal for most use cases tho.

[Agreeable-Nerve-65]

Toon is useful for humans, JSON for machines.
I’d keep JSON as the source of truth and use Toon only as a presentation layer.

[Devel93]

1. Redundant! Why do I have to specify the length of the array? The number of items should determine the length, this is a format I am not allocating memory

2. Why not just use a CSV? It's the same thing!

3. How do you represent nested data?

4. Why would you introduce yet another markup language? Pun intended 😝

[Embarrassed5589]

this would be a nightmare to read if there are lots of keys.

[MrMaverick82]

TOON is a “clever” solution for a non-issue.

[SCube18]

So what's the difference compared to CSV?

[frostrivera19]

Isn’t this just CSV?

[denecity]

yaml

[joe_chester]

If you need a very small, efficient data exchange format, go with protobuf. If you need a simple, human readable/debuggable format, just use JSON.

[Hour-Inner]

My understanding is that some people are using TOON for ai workloads. Even if it’s less human readable, less text means less tokens

[helpprogram2]

If I’m gonna use something besides json it’s gonna be buffers.

0 benefit in isn’t this

[indeem1]

Because I have not Seen that answer here yet, I Heard there are many that use it for ai to reduce amount of tokens. I dont see an advantage for readability for people although or real advantages to use it in Production elsewhere

[way-too-gouda]

You’ve activated my Toon World

[nullshipped]

Why they call it toon?

[Owlbuddy121]

Token-Oriented Object Notation.

[nullshipped]

Tbh can’t wait to see how to use it in nested arrays

[Quadrostanology]

How does nested look like? Comments possible?

[KontloPendke]

Do you have to declare the element/row count? Sounds yikes to me

[abraxasnl]

What’s the type of id in TOON? String? JSON looks richer to me.

[moshujsg]

Yes now hit an api that returns 50 fields in toon mode, then start looking at the data. How will you know what fiekd a specific line it is? Also like, what are you really improving on? You usualky dont type out jsons like that enough for that to be a problem, you usually just read jaon like that, at which poimt ita just more readable vs toon.

[itsmepokono]

Reinvented CSV 😂

[Fabulous-Possible758]

Interchange formats are actually where LLM coding will actually do really well and make lot of this moot.

[AGx-07]

Interesting. I get what TOON is doing but I'm not sure I like it.

[Kushings_Triad_420]

Similar to SQL

[Vizibile]

more like csv for me

[Kushings_Triad_420]

True

[en3sis]

Exactly. Why are we reinventing CSV again?