Show HN: I built a fast RSS reader in Zig
12 comments
·December 16, 2025A1aM0
The 'once a day' fetching limitation is a fascinating idea. It really captures the vibe of reading a physical newspaper in the morning rather than constantly checking for updates. I think many of us could use a tool that enforces a bit of 'digital silence' like this.
mocheeze
In middle school (age 11-13 in the late '90s, USA) I had a hand-me-down Palm Pilot (probably upgraded to Handspring in there). I'd leave it on my serial(?) port cradle and have it download my daily news from sites like IGN and Slashdot over 56K before I woke up. I was also the kid that regularly read the "Time Life for Kids" mags they'd pass out to us in homeroom. That's the outlet I learned about Napster from and hooked my school onto. Your comment reminded me of those days. Now I'm still desperately hooked on RSS since the early days.
ETA: When I was a late teen I ended up managing a bunch of younger teams for a free mod for an indie PC game called Blockland. I had them code up IRC and RSS capabilities into the mod from scratch in the Torque Game Engine's custom TorcueScript. I couldn't believe what those kids were capable of. They all went into programming, engineering, or founding their own companies out of highschool and college. If one of them told me something was impossible I'd just tell them that I saw that a competing mod already figured it out. Magically my dudes had a solution really quick lol. Sometimes when you have limited resources and/or experience the old and proven ways are just as good.
Was great when they had all that XML experience in a weird scripting language and I asked them to implement Jabber in-game from my Dreamhost shared-hosting plan. Crazy what a bunch of teens can do for an online Lego-like game.
Thanks for letting this older dude wax nostalgic off the rails. Hope it reminds others on HN about early hacking days like OP's project.
A1aM0
Love it. It’s funny how we are now building modern tools just to try and get back that simple 'Palm Pilot morning read' vibe.
keyle
Nice work, I did mine in C, using Termbox2, in a very suckless fashion (config.h & make install)
I like the idea of the daily digest.
That gave me a good chuckle:
Starts in milliseconds and parses hundreds of items in seconds.
lknuth
I think its cool that more people are building what I call "calm tech". More technology should try to serve a purpose quickly and then get out of the way instead of trying to artificially stay on your screen as long as possible.
Incidentally, I built my own calm RSS reader some time ago that has many similar ideas to yours: https://github.com/lukasknuth/briefly
superstarryeyes
nice! yeah, i agree. calm tech is a nice way to put it. the current big platforms are highly tuned to keep people engaged and enraged to the max, rss is kind antithesis of that. that's probably why big companies try to bury and hide it. youtube and reddit still give pretty good rss support though, which is nice.
ekjhgkejhgk
Why MIT and not GPL3?
superstarryeyes
why not? isn't mit just objectively a better license for open source? i just hope rss would make a comeback to make the internet a little saner again, and if someone wants to use hys source code as a base for their own rss reader, whether commercial or not, great!
ekjhgkejhgk
Explain what you mean by "objectively better"? Your response makes it sound like you don't know the difference and are doing it because everybody else does it. It also makes it sounds like you don't understand the difference between open source software and free software. Both are free licenses, open source is just one part of it.
The main difference is that GPL3 is a copyleft license, whereas MIT is not. Meaning that legally there is nothing in the license preventing a company from taking your code and using it for their purposes without having to contribute to improve the code.
superstarryeyes
i know the difference. i use gpl3 in my other project lue for example. i meant objectively better for the open source community. the spread of new ideas benefits from the mit license because the ideas in the code can travel farther.
the reason i picked mit is because rss is in a rough spot right now. the tech isn't mainstream, and big companies are trying to squash it since it doesn't drive engagement like the infinite scroll. anything that helps rss move forward is a win, and the mit license makes that easier.
Well, I certainly tried. I had to, because it has a certain quirk inspired by "digital minimalism."
The quirk is that it only allows you to fetch new articles once per day (or X days).
Why? Let me explain...
I want my internet content to be like a boring newspaper. You get it in the morning, and you read the whole thing while sipping your morning coffee, and then you're done! No more new information for today. No pings, no alerts, peace, quiet, zen, etc.
But with that, I needed it to be able to fetch all articles from my hundreds of feeds in one sitting. This is where Zig and curl optimisations come in. I tried to do all the tricks in the book. If I missed something, let me know!
First off, I'm using curl multi for the network layer. The cool thing is it automatically does HTTP/2 multiplexing, which means if your feeds are hosted on the same CDN it reuses the same connection. I've got it configured to handle 50 connections total with up to 6 per host, which seems to be the sweet spot before servers start getting suspicious. Also, conditional GETs. If a feed hasn't changed since last time, the server just says "Not Modified" and we bail immediately.
While curl is downloading feeds, I wouldn't want CPU just being idle so the moment curl finishes downloading a single feed, it fires a callback that immediately throws the XML into a worker thread pool for parsing. The main thread keeps managing all the network stuff while worker threads are chewing through XML in parallel. Zig's memory model is perfect for this. Each feed gets its own ArenaAllocator, which is basically a playground where you can allocate strings during parsing, then when we're done, we just nuke the entire arena in one go.
For parsing itself, I'm using libexpat because it doesn't load the entire XML into memory like a DOM parser would. This matters because some podcast feeds especially are like 10MB+ of XML. So with smart truncation we download the first few X mb's (configurable), scan backwards to find the last complete item tag, cut it there, and parse just that. Keeps memory usage sane even when feed sizes get massive.
And for the UI I just pipe everything to the system's "less" command. You get vim navigation, searching, and paging for free. Plus I'm using OSC 8 hyperlinks, so you can actually click links to open them on your browser. Zero TUI framework needed. I've also included OPML import/export and feed groups as additional features.
The result: content from hundreds of RSS feeds retrieved in matter of seconds, and peace of mind for the rest of the day.
The code is open source and MIT licensed. If you have ideas on how to make it even faster or better, comment below. Feature requests and other suggestions are also welcome, here or GitHub.