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Joe Walnes

@waln.es
2K followers 1.7K following 176 posts

Building new stuff at Stripe. Previously: Apple, Google, Thoughtworks, trading, founder. Open source: websocketd, xstream, hamcrest, and others… github.com/joewalnes linkedin.com/in/joewalnes x.com/joewalnes

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Joe Walnes @waln.es · 04/02/2026
I've cracked it! A foolproof unbreakable human vs AI captcha test. --- Are you human? ◯ Yes - I'm definitely human ◯ Yes — I'm definitely human
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Joe Walnes @waln.es · 13/09/2025
Cute LEGO eyeball creature thingy www.reddit.com/r/LV426/comm...
reddit.com
From the LV426 community on Reddit: Build your own LEGO Eyeball Alien! (Cat sold separately)
Explore this post and more from the LV426 community
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Joe Walnes @waln.es · 20/08/2025
What web analytics tools y’all using these days? Looking for: - lightweight (fast loading) - privacy centric: no creepiness, no ad tracking, just give me high level insights, - GDPR friendly - simple dashboards - alerts of spikes - not too expensive to run on many sites (doesn’t have to be free)
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Joe Walnes @waln.es · 19/08/2025
teenytiny.ai Its retro
teenytiny.ai
TeenyTiny AI
Replace your slow, expensive, large language models with instantaneous, free, tiny language models. OpenAI API compatible. Probably no down side.
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Joe Walnes @waln.es · 13/07/2025
SaaS builders: which libraries/frameworks are you using to interact with LLMs? How are you dealing with LLM costs? Is it a problem?
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Joe Walnes @waln.es · 13/07/2025
The Commodore 64 is back! commodore.net
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Joe Walnes @waln.es · 30/06/2025
A car commute is the perfect amount of time to build and ship ideas. I just gotta keep my eyes on the road. Looking for a fully voice controlled AI coding tool, ideally works on phone. What tools can help me do this? Or do I need to vibe code it myself (while not driving!)
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Joe Walnes @waln.es · 27/06/2025
Like talking about AI and the future of business? Like creating content and building community? Come help us! stripe.com/jobs/listing...
stripe.com
Community Communications, Product/Developer
Help increase the GDP of the internet as part of our Communications team.
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Joe Walnes @waln.es · 24/06/2025
The best line I've ever added to CLAUDE.md: "Before each commit, reflect on the lessons we've learned together and update CLAUDE.md for future use. Focus on generic patterns and techniques, not specifics of a single feature."
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Matt Godbolt @matt.godbolt.org · 23/05/2025
Experimenting with something like this for @compiler-explorer.com - wondering what your thoughts are? AI is getting everywhere, and can be divisive. I'm hoping something like this - so long as I can get the output quality high enough - is a net benefit to help folks learn more about their code.
A screenshot of Compiler Explorer showing an "AI Explain this" view. The source code is: 

bool isspc(char c) { 
    return c == '\n' || c == '\r' || c == '\t' || c == ' ';
}

The asm is:
isspc(char):
        mov     ecx, edi
        cmp     cl, 33
        setb    dl
        movabs  rax, 4294977024
        shr     rax, cl
        and     al, dl
        ret

Below is a "Claude Explain" window with:

The function isspc(char) is compiled to an efficient bit manipulation technique to check for whitespace characters. Let's break down the assembly instructions:

mov ecx, edi

Copies the input character from the edi register (first function argument) to ecx
cl will contain the lowest 8 bits (the character)
cmp cl, 33

Compares the character against decimal 33
This is a preliminary check to quickly filter out non-whitespace characters
setb dl

Sets the dl register to 1 if the character is below 33 (space, tab, newline, etc.)
Uses a conditional set instruction
movabs rax, 4294977024

Loads a pre-computed 64-bit constant
This constant represents a bit mask for whitespace detection
shr rax, cl

Shifts the bit mask right by the character's value
This dynamically positions the mask based on the input character
and al, dl

Performs a bitwise AND between the shifted mask and the previous condition
Produces the final boolean result in al
ret

Returns the result (0 or 1) in al
This implementation is a highly optimized branchless method for checking whitespace characters, using bit manipulation instead of multiple comparisons. It avoids conditional jumps, which can be slower on modern CPUs.

The code checks for space (' '), newline ('\n'), carriage return ('\r'), and tab ('\t') in a single, efficient operation.
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Joe Walnes @waln.es · 07/05/2025
We’ve been busy. Starting now… www.youtube.com/live/AWXAd2G...
youtube.com
Stripe Sessions 2025 | Product keynote
YouTube video by Stripe
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Joe Walnes @waln.es · 17/04/2025
New font from Microsoft. I like it. It’s not Comic Sans. microsoft.design/articles/int...
microsoft.design
Introducing Kermit: A typeface for kids - Microsoft Design
Using design to empower children by making reading easier, improving comprehension, and helping dyslexics.
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Joe Walnes @waln.es · 15/04/2025
Ergo mech portable setup… 3 modes: 1. Full: best ergonomics. Takes about 20 seconds to setup. 2: Quick: busting out laptop quickly. Takes about 5 seconds. 3: Tiny: works on lap, plane tray, etc.
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Joe Walnes @waln.es · 06/04/2025
The Studio S1E2 is an incredible piece of self-referential cinematography
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Joe Walnes @waln.es · 06/03/2025
March 19, Stripe's hosting a live office hours on Stripe's open source Agent Toolkit. (Our team is hiring btw) www.youtube.com/watch?v=vdXP...
youtube.com
Introducing the Stripe Agent Toolkit
YouTube video by Stripe Developers
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Joe Walnes @waln.es · 05/02/2025
We’ll know we’ve reached AGI when we see models that can figure out the naming convention of models.
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Red Blob Games @redblobgames.com · 04/02/2025
What happens when LLMs train on code that's popular but wrong? zdimension.fr/everyone-get... explores this, with interactive diagrams exploring the error
zdimension.fr
Everyone gets bidirectional BFS wrong
People really need to stop blindly copying code from the Internet.
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Joe Walnes @waln.es · 05/02/2025
httptap. How this tool decrypts https traffic is fascinating and elegant. How the tool was made is even more so. github.com/monasticacad...
github.com
GitHub - monasticacademy/httptap: View HTTP/HTTPS requests made by any Linux program
View HTTP/HTTPS requests made by any Linux program - monasticacademy/httptap
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Joe Walnes @waln.es · 01/02/2025
Looking at a decade of GitHub stars on one of my projects. It hit Hacker News front page twice. Pretty obvious when. But aside from that, it shows steady and remarkably constant organic growth. I have no idea how, and I'd like to learn more. How do you discover new projects?
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Robert Sundling @robertsundling.bsky.social · 22/01/2025
I just built a hybrid 16-bit MS-DOS/32-bit Windows executable by hand in NASM so that both parts could share common data sections. To fully conform to the PE specs (which I prefer, for long-term compatibility), the file size must be rounded up to the nearest 512 bytes. So I had some space left over…
Hex dump of an executable program, with ASCII art of spiders and a text warning about them.
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Joe Walnes @waln.es · 22/01/2025
Come work with me stripe.com/jobs/listing...
stripe.com
Software Engineer, Experimental Projects
Help increase the GDP of the internet as part of our Data & Data Science team.
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Joe Walnes @waln.es · 17/01/2025
The Imperial March. The most iconic Star Wars theme. But it was never in the original Star Wars! (Introduced in Empire Strike Back)
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Joe Walnes @waln.es · 01/01/2025
Oh wow… I just stumbled across @hofferth.net, who’s designed many many many many exciting Mac Mini enclosures!
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Joe Walnes @waln.es · 01/01/2025
A great summary of LLMs in 2024 by @simonwillison.net simonwillison.net/2024/Dec/31/...
simonwillison.net
Things we learned about LLMs in 2024
A lot has happened in the world of Large Language Models over the course of 2024. Here’s a review of things we figured out about the field in the past …
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Joe Walnes @waln.es · 24/12/2024
What are you sneakily building in those days off work?
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Joe Walnes @waln.es · 24/12/2024
December is Advent of Code. Next up: DRY January. In January.
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luokai @luok.ai · 23/12/2024
Following WonderJourney, WonderWorld has arrived as an innovative framework that allows users to generate interactive 3D scenes from a single image and view the created scenes with low latency, including examples of different camera path styles: rotational, curvy, and straight.
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Joe Walnes @waln.es · 20/12/2024
sometimes you only have terminal access to sql but still want to visualize data...
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Joe Walnes @waln.es · 20/12/2024
favorite starter packs for saas founders, solo builders, etc?
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Justin Jackson @justinjackson.ca · 18/12/2024
I wrote a blog post titled "What's happening with founders over 40?" that ended up on Hacker News. I got a lot of comments and reactions to the piece, so I thought I'd respond to those in this podcast: justin.transistor.fm/episodes/too... Here's a little video sample:
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Joe Walnes @waln.es · 18/12/2024
I’ve totally got the hang of AI assisted code generation.
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Joe Walnes @waln.es · 18/12/2024
What are you building right now?
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Joe Walnes @waln.es · 17/12/2024
One day, I’ll get the syntax of a markdown link correct. But today is not that day.
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Joe Walnes @waln.es · 17/12/2024
Hello @jeff-weinstein.bsky.social! Welcome to this one.
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Joe Walnes @waln.es · 17/12/2024
Moved to the mountains in California for the weather. December (so far): ☑️ Rain floods ☑️ Earthquake ☑️ Tsunami ☑️ Tornado 🌪️ ⬛️ Godzilla
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Joe Walnes @waln.es · 16/12/2024
Wish I could repost things from X here. Oh I can, with links. Anyway... we're interested in hearing if you have a case for this? x.com/jeff_weinste...
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Joe Walnes @waln.es · 16/12/2024
Been reading up on ATProto. Feeds, hierarchies, decentralized servers, propagation, attachments, crossposting, subscriptions… This all seems eerily familiar. Is it just a modernized NNTP?
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Joe Walnes @waln.es · 16/12/2024
Who went to NeurIPS? Highlights?
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Reposted by Joe Walnes
Hank Green @hankgreen.bsky.social · 14/12/2024
I don’t know why I’m still so pissed off that the answers to “what, where, and when” are “that, there, and then.”
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Joe Walnes @waln.es · 15/12/2024
My fav programming podcast with Ben & Matt…
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Joe Walnes @waln.es · 14/12/2024
Rust C bindings often appear at the edge of a library. These should be called crusts.
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Joe Walnes @waln.es · 13/12/2024
Very much looking forward to OpenAI rolling out Sora in California.
Screenshot of sora.com with error message “sora is not available in your country yet”
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Reposted by Joe Walnes
Ken Milne MD @thesgem.bsky.social · 12/12/2024
Holiday + Dad + Nerd = Stats Joke #MedSky
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Joe Walnes @waln.es · 11/12/2024
How did your day go? Mine was somewhat fun.
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Joe Walnes @waln.es · 10/12/2024
I… I had no idea this was a thing…
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Joe Walnes @waln.es · 10/12/2024
Favorite (non software based) productivity technique?
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kepano @stephango.com · 04/12/2024
Each year I ask myself these 40 questions. This will be my eleventh year. It's still one of my favorite rituals. It helps me see how phases of my life wax and wane. Each year new translations come in. We're up to 30 languages! Thank you to all the contributors 🥰 stephango.com/40-questions
1.  What did you do this year that you’d never done before?
2.  Did you keep your new year’s resolutions?
3.  Did anyone close to you give birth?
4.  Did anyone close to you die?
5.  What cities/states/countries did you visit?
6.  What would you like to have next year that you lacked this year?
7.  What date(s) from this year will remain etched upon your memory, and why?
8.  What was your biggest achievement of the year?
9.  What was your biggest failure?
10.  What other hardships did you face?
11.  Did you suffer illness or injury?
12.  What was the best thing you bought?
13.  Whose behavior merited celebration?
14.  Whose behavior made you appalled?
15.  Where did most of your money go?
16.  What did you get really, really, really excited about?
17.  What song will always remind you of this year?
18.  Compared to this time last year, are you: happier or sadder? Thinner or fatter? Richer or poorer?
19.  What do you wish you’d done more of?
20.  What do you wish you’d done less of?21.  How are you spending the holidays?
22.  Did you fall in love this year?
23.  Do you hate anyone now that you didn’t hate this time last year?
24.  What was your favorite show?
25.  What was the best book you read?
26.  What was your greatest musical discovery of the year?
27.  What was your favorite film?
28.  What was your favorite meal?
29.  What did you want and get?
30.  What did you want and not get?
31.  What did you do on your birthday?
32.  What one thing would have made your year immeasurably more satisfying?
33.  How would you describe your personal fashion this year?
34.  What kept you sane?
35.  Which celebrity/public figure did you admire the most?
36.  What political issue stirred you the most?
37.  Who did you miss?
38.  Who was the best new person you met?
39.  What valuable life lesson did you learn this year?
40.  What is a quote that sums up your year?
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Joe Walnes @waln.es · 08/12/2024
Answer: both
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mary🐇 @mary.my.id · 19/10/2024
introducing atcute, a collection of lightweight TypeScript packages for AT Protocol API client, OAuth client, utility packages for various data formats, Bluesky-specific utility packages for rich text and posting they're all covered!
screenshot of the project's readme file
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Joe Walnes @waln.es · 07/12/2024
Let's play.... C ✨ or 🌟 CSS ?
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