Show HN: Sosumi.ai – Convert Apple Developer docs to AI-readable Markdown

53 _mattt 32 8/29/2025, 1:30:16 PM sosumi.ai ↗
I got tired of Claude hallucinating Swift APIs. It does a good job at Python and TypeScript, but ask it about SwiftUI and it's basically guessing.

The problem? Apple's docs are JavaScript-rendered, so when you paste URLs into AI tools, they just see a blank page. Copy-pasting works but... c'mon.

So I built something that converts Apple Developer docs to clean markdown. Just swap developer.apple.com with sosumi.ai in any Apple docs URL and you get AI-readable content.

For example:

- Before: https://developer.apple.com/documentation/swift/double

- After: https://sosumi.ai/documentation/swift/double

The site itself is a small Hono app running on Cloudflare Workers. Apple's docs are actually available as structured data, but Apple doesn't make it obvious how to get it. So what this does is map the URLs, fetch the original JSON, and render as Markdown.

It also provides an MCP interface that includes a tool to search the Apple developer website, which is helpful.

Anyway, please give this a try and let me know what you think!

Comments (32)

dewey · 2h ago
For those wondering about the name, it has a fun story behind it: https://en.wikipedia.org/wiki/Sosumi
oneeyedpigeon · 1h ago
"AI-readable Markdown" — can't we just say "Markdown"? I'm serious about this, why are we focussing on making things accessible to AI when they should just be machine-readable and accessible to human beings in the first place? No need to taint this by bringing AI into it.
forrestthewoods · 1h ago
> why are we focussing on making things accessible to AI

Because that’s the authors actual goal? To take a web page that looks fine to human eyes but is unintuitively not accessible to AI. That’s genuinely useful and valuable.

Sure it’s no different than converting it to markdown for human eyes. But it’s important to be clear about not just WHAT but also WHY.

C’mon now. This isn’t controversial or even bad.

danielfalbo · 37m ago
How to reliably HTML to MD for any page on the internet? I remember struggling with this in the past

How hard would it be to build an MCP that's basically a proxy for web search except it always tries to build the markdown version of the web pages instead of passing HTML?

Basically Sosumi.ai but instead of working on only for Apple docs it works for any web page (including every doc on the internet)

tiahura · 39s ago
jcoletti · 1h ago
This is awesome and timely for me...going to give it a whirl. Thanks for building. Also, there should totally be an easter egg where clicking something somewhere plays the sound!
_mattt · 49m ago
Great idea! I just added that. Try clicking the icon in the header.
fabiensanglard · 41m ago
It is for the same reasons LLM are struggling to produce something that compile in Rust? I was under the impression that most of Rust documentation was plain HTML.
tempodox · 1h ago
An “AI” that makes text “AI”-readable. How does that make any sense?
h1fra · 1h ago
I think it's safe to assume most big players have browser rendering enabled (I hope so). imo AI is struggling with a lot of languages that are not as popular as javascript, mostly because it's more niche and you don't get a lot of good examples on the web.
_mattt · 1h ago
In my experience, coding agents seem to do a normal fetch when provided links. Which makes sense — headless browser automation is expensive, and only really necessary for interacting with a webpage.

But with these RLHF'd AIs, being confident and helpful as they are, it took me a while to realize that they couldn't actually read the Apple developer links I was giving them. Like a kid who can't read the chalkboard, but doesn't realize they need glasses.

h1fra · 54s ago
It's expensive for sure, but probably a drop in the water compared to the cost of renting H100. Plus, it would be a massive boost in terms of data quality/quantity for them. But maybe you are right, I'm just surprised it's not the case
hirvi74 · 1h ago
> "Ever notice Claude struggling to write Swift code?"

Yes, that is why I quit using Claude and swapped to ChatGPT about a year ago. I've had substantially less issues with GPT.

asimovDev · 1m ago
I remember copilot with GPT helping me export Swift to C for interop. Something I could hardly find good examples and info on in my google searches.
guestbest · 57m ago
ChatGPT does swift and objc remarkably well including UIKit and core data. Its gotten much better for project files with gpt5-mini
ChrisMarshallNY · 1h ago
I don't even bother trying to render docc catalogs into JS. It's a royal pain that breaks easily.

If GitHub could support .docc files, that would be great. Otherwise, I still use Jazzy Docs.

_mattt · 58m ago
Once upon a time, I built a project called `swift-doc`, which eventually got Sherlocked. I think what I was most upset about was their decision to call their thing "DocC". Like, adding redundant consonants to avoid name collisions is my shtick.

Long live Jazzy.

ChrisMarshallNY · 57m ago
I love your stuff!

Thanks!

smerrill25 · 2h ago
As someone who is currently building my first iOS app, I am extremely happy to have this. This will be much nicer doing my animation documentation.
croes · 38m ago
Wasn’t one of the benefits of AI that we don’t need special documents for AI to understand the data?
thomask1995 · 2h ago
Very interesting. You have any before and after examples?

Curious how it handles some of the concurrency stuff. Actors, async/await etc..

_mattt · 2h ago
Sure, here are a few more examples:

- https://developer.apple.com/documentation/swift/tasklocal

- https://sosumi.ai/documentation/swiftui/button

- https://sosumi.ai/documentation/foundation/measurement

Most of the docs about the language itself live on swift.org (e.g. https://docs.swift.org/swift-book/documentation/the-swift-pr...). I've had pretty good luck getting Claude to write modern Swift code by saying things like "Use Swift 6 structured concurrency instead of GCD". But I could totally see expanding sosumi to include swift.org content, too.

Edit: Another Swift developer life hack: for new language features, copy-pasting the Swift Evolution proposal works pretty well! https://github.com/swiftlang/swift-evolution/tree/main/propo...

wahnfrieden · 1h ago
Are you making use of the new markdown files Apple started shipping inside Xcode? They’re probably copyrighted though
edomyrots · 1h ago
Do you have a public repo? Would love to see how it's working.
_mattt · 1h ago
Not yet, but I plan to open source it soon. Just gotta tidy up a little bit, you know?
sneak · 1h ago
Why do people always say this?

It’s ok to just start coding with a public repo. Code isn’t a secret.

oneeyedpigeon · 1h ago
I think it's because, in the world of programming, people are incredibly critical. Just try putting absolutely anything out there, and you'll get certain types of people picking it apart.

I remember an early experience in my working career, when someone was sharing their sample code with a group, to demonstrate a particular concept. And one of those present picked them up on their use of magic numbers, as if that was at all relevant in the context.

I don't blame anyone for being wary of showing their work in progress. Painters often don't like their subjects trying to take a sneek peak at their work in progress, as another example.

joshstrange · 1h ago
- Keys/tokens in the code. Yes, it’s bad practice but for a hobby/personal project it’s not the end of the world

- Not wanting to get roasted

- Open source = dealing with a lot of entitlement

And the list goes on. Putting code out into the world (publicly) often sets you up for future obligation of some kind (even if it’s just saying “no”).

None of this is a stance against open source, but I understand where people are coming from.

miki123211 · 1h ago
Just saying, sites like these are also pretty great for accessibility, screen reader users in particular.

I think this one would be slightly better if it rendered that Markdown as simple HTML if accessed through a real browser, but I can imagine even this version being pretty useful.

I think it could also make the "Small web" crowd pretty happy too.

diimdeep · 1h ago
Could you share what is your motivation behind doing whole domain and web hosting ?

Personally I feel that this whole AI induced problem should even exist in the first place, but even then it is ridiculous, that you have to query some web api to solve this problem, why not just publish parsed and converted to .md set of local files and be done with it.

_mattt · 1h ago
I agree, it'd be great if Apple provided accessible documentation in the first place. Time was, Apple published self-contained docsets that you could download and read offline.

Apple's ToS pretty explicitly forbid the kind of automation required to download everything. But even if someone did that, it'd only be a snapshot in time. And a lot can can change between OS releases.

As for the hosted web app, I wanted to provide this as a public service. I plan to open source it, so anyone can self-host instead, if they're inclined.

diimdeep · 28m ago
Yeah, pre Swift documentation was very sufficient, dense and locally explorable, since then documentation started to resemble .h copy pasta without comments.