Juan Castillo
@0x5d.bsky.social
Software engineer. Go, Rust, infra. SWE @ attention.com. Prev. Platform @ Mercado Libre, Cloud @ Redpanda.
Tears for Fears already invented every type of music back in the 80s.
October 25, 2025 at 1:33 PM
Tears for Fears already invented every type of music back in the 80s.
Reposted by Juan Castillo
Folks, we have the best π: lcamtuf.substack.com/p/folks-we-h...
Folks, we have the best π
In the past couple of months, I published a number of articles on recreational math.
lcamtuf.substack.com
September 15, 2025 at 6:44 AM
Folks, we have the best π: lcamtuf.substack.com/p/folks-we-h...
YONTBAQOO
You only need to build a query optimizer once
You only need to build a query optimizer once
September 1, 2025 at 10:46 PM
YONTBAQOO
You only need to build a query optimizer once
You only need to build a query optimizer once
I've been using Pulumi for >1 mo, and have spent the weekend doing a small project with it. So far I can't shake the feeling that I shouldn't have so much power while defining company-critical infra.
Give me my TF, where even the most inoffensive local-exec will rise eyebrows.
Give me my TF, where even the most inoffensive local-exec will rise eyebrows.
August 31, 2025 at 10:06 PM
I've been using Pulumi for >1 mo, and have spent the weekend doing a small project with it. So far I can't shake the feeling that I shouldn't have so much power while defining company-critical infra.
Give me my TF, where even the most inoffensive local-exec will rise eyebrows.
Give me my TF, where even the most inoffensive local-exec will rise eyebrows.
I almost became the first victim of “LLM word choice-induced cardiac arrest” today.
August 19, 2025 at 12:55 AM
I almost became the first victim of “LLM word choice-induced cardiac arrest” today.
This post makes me feel like it’s 2015 and I love it.
August 11, 2025 at 12:36 AM
This post makes me feel like it’s 2015 and I love it.
Reposted by Juan Castillo
Beautiful essay by @henrikkarlsson.bsky.social on learning to realise that what you want to do is, in fact, possible www.henrikkarlsson.xyz/p/agency
On agency
Or, how to handle being sentenced to freedom, and handle it effectively, and authentically, and responsibly
www.henrikkarlsson.xyz
July 7, 2025 at 12:33 PM
Beautiful essay by @henrikkarlsson.bsky.social on learning to realise that what you want to do is, in fact, possible www.henrikkarlsson.xyz/p/agency
Blindsight
July 4, 2025 at 6:52 PM
Blindsight
This applies to life in general, now that I think about it.
The game is more fun if you commit to the bit. But also: sometimes the “wrong” option turns out to be the best choice.
June 14, 2025 at 7:20 PM
This applies to life in general, now that I think about it.
Copilot adds “nitpick” comments on PR reviews, therefore confirming my hunch that we have reached AGI (it is now indistinguishable from an unengaged engineer with bad communication skills).
June 3, 2025 at 1:57 PM
Copilot adds “nitpick” comments on PR reviews, therefore confirming my hunch that we have reached AGI (it is now indistinguishable from an unengaged engineer with bad communication skills).
Reposted by Juan Castillo
I agree with Mehdi that I think we’re moving into a world that incentivizes smaller orgs and teams. You can do so much with very few engineers today
I don’t think I buy the argument that mid-sized companies are dying though. You’ll still need to scale up eventually, just later
I don’t think I buy the argument that mid-sized companies are dying though. You’ll still need to scale up eventually, just later
What if medium-sized software companies are slowly dying?
I’ve seen more and more solo-preneurs and small teams shipping fast, staying lean — and still landing enterprise customers.
So what if scaling headcount… wasn’t actually necessary?
blog.mehdio.com/p/the-slow-d...
I’ve seen more and more solo-preneurs and small teams shipping fast, staying lean — and still landing enterprise customers.
So what if scaling headcount… wasn’t actually necessary?
blog.mehdio.com/p/the-slow-d...
The Slow Death of Medium-Sized Software Companies
What if scaling was no longer the goal? And what would that mean for software engineers?
blog.mehdio.com
June 1, 2025 at 6:45 PM
I agree with Mehdi that I think we’re moving into a world that incentivizes smaller orgs and teams. You can do so much with very few engineers today
I don’t think I buy the argument that mid-sized companies are dying though. You’ll still need to scale up eventually, just later
I don’t think I buy the argument that mid-sized companies are dying though. You’ll still need to scale up eventually, just later
10 pages a day, ~1 book a month. By the end of the year you’ll be 12 books ahead of the average.
May 18, 2025 at 11:59 PM
10 pages a day, ~1 book a month. By the end of the year you’ll be 12 books ahead of the average.
Reposted by Juan Castillo
This is the official account for Matt Stikker, illustrator based in Portland, OR. Horror, fantasy & heavy metal art in ink & paint, and sometimes pixels. Past & present clients include Magic: the Gathering, Lurking Class, Metallica, Santa Cruz, more. I’m on IG @bargainbinblasphemy, but call me Matt
November 30, 2024 at 7:27 PM
This is the official account for Matt Stikker, illustrator based in Portland, OR. Horror, fantasy & heavy metal art in ink & paint, and sometimes pixels. Past & present clients include Magic: the Gathering, Lurking Class, Metallica, Santa Cruz, more. I’m on IG @bargainbinblasphemy, but call me Matt
The world is going through some shitty stuff, but it’s so weird to see US people post about it on here all the time.
As far as I can see, everyone who sees your posts agrees with them, so what’s the point?
And even if they didn’t - I’ve never seen anyone change their minds because they read a tweet.
As far as I can see, everyone who sees your posts agrees with them, so what’s the point?
And even if they didn’t - I’ve never seen anyone change their minds because they read a tweet.
March 12, 2025 at 4:03 PM
The world is going through some shitty stuff, but it’s so weird to see US people post about it on here all the time.
As far as I can see, everyone who sees your posts agrees with them, so what’s the point?
And even if they didn’t - I’ve never seen anyone change their minds because they read a tweet.
As far as I can see, everyone who sees your posts agrees with them, so what’s the point?
And even if they didn’t - I’ve never seen anyone change their minds because they read a tweet.
❤️
It's spring! The beast lumbers, the mind moves, art demands doing but instead I write frivolities.
I have made a substack. It will contain simple thoughts, texts on art, and pictures.
It begins with a tutorial of sorts
rostovjanka.substack.com/p/how-to-age...
I have made a substack. It will contain simple thoughts, texts on art, and pictures.
It begins with a tutorial of sorts
rostovjanka.substack.com/p/how-to-age...
How to age faster
A tutorial.
rostovjanka.substack.com
March 9, 2025 at 12:18 PM
❤️
See y’all at @hytradboi.bsky.social ! Get your tix at www.hytradboi.com/2025
HYTRADBOI 2025
HYTRADBOI is a fun online conference about databases, programming languages, and everything in between.
www.hytradboi.com
February 28, 2025 at 3:24 AM
See y’all at @hytradboi.bsky.social ! Get your tix at www.hytradboi.com/2025
I was reading and annotating the Viewstamped Replication Revisited paper, and all of a sudden, Preview (on Mac) seems to have flushed all my notes down the toilet.
What are some good apps to read papers on? #pwl #ismacosthenewwindows #distsys
What are some good apps to read papers on? #pwl #ismacosthenewwindows #distsys
February 25, 2025 at 11:25 PM
I was reading and annotating the Viewstamped Replication Revisited paper, and all of a sudden, Preview (on Mac) seems to have flushed all my notes down the toilet.
What are some good apps to read papers on? #pwl #ismacosthenewwindows #distsys
What are some good apps to read papers on? #pwl #ismacosthenewwindows #distsys
It’s hard to make a pretty diagram of a complex system.
February 24, 2025 at 9:12 PM
It’s hard to make a pretty diagram of a complex system.
People focus a lot on the law of diminishing returns, and not enough in the law of noob gains: when you have nothing (incl. knowledge), gaining anything is a ∞% delta.
February 24, 2025 at 1:48 AM
People focus a lot on the law of diminishing returns, and not enough in the law of noob gains: when you have nothing (incl. knowledge), gaining anything is a ∞% delta.
Gut feeling: if you have a big enough distributed system, and you aren’t using Kafka, you’re reinventing it.
February 17, 2025 at 6:30 PM
Gut feeling: if you have a big enough distributed system, and you aren’t using Kafka, you’re reinventing it.
Going through my private repos and apparently I tried to write a book about DevOps 9 yrs ago.
Yikes.
Yikes.
February 16, 2025 at 2:24 AM
Going through my private repos and apparently I tried to write a book about DevOps 9 yrs ago.
Yikes.
Yikes.
If you can estimate accurately how long it would take you to make something, leave it to an LLM and find something valuable to focus on instead.
February 15, 2025 at 2:45 AM
If you can estimate accurately how long it would take you to make something, leave it to an LLM and find something valuable to focus on instead.
The thing about software eng is that, unlike some other professions, many people get into this for fun. It's all about play and curiosity.
If you're just "working", people that are playing are gonna leave you behind in the time it takes to flip a bit.
If you're just "working", people that are playing are gonna leave you behind in the time it takes to flip a bit.
February 2, 2025 at 11:24 PM
The thing about software eng is that, unlike some other professions, many people get into this for fun. It's all about play and curiosity.
If you're just "working", people that are playing are gonna leave you behind in the time it takes to flip a bit.
If you're just "working", people that are playing are gonna leave you behind in the time it takes to flip a bit.