Paulus Esterhazy
@pesterhazy.bsky.social
Startup tech lead based in Berlin. Cur: Founding Engineer at telli (YC F24); Prev: Pitch
@mattpocock.com in your capacity as typescript whisperer, have you blogged about "function parameter bivariance"? I'd be curious if you have practical advice how to avoid the problem I describe in this gist gist.github.com/pesterhazy/4...
typescript interface wat
typescript interface wat. GitHub Gist: instantly share code, notes, and snippets.
gist.github.com
August 9, 2025 at 2:34 PM
@mattpocock.com in your capacity as typescript whisperer, have you blogged about "function parameter bivariance"? I'd be curious if you have practical advice how to avoid the problem I describe in this gist gist.github.com/pesterhazy/4...
Vibecode, not too much, mostly UI
June 18, 2025 at 2:01 PM
Vibecode, not too much, mostly UI
Reposted by Paulus Esterhazy
I could use a nice trip to somewhere in Europe or the UK.
I'd like to sponsor my trip by doing useful work with your company. I have a lot of skill and experience in software delivery, code craft, and team management.
Consider contracting me for a few days. I would love to help.
I'd like to sponsor my trip by doing useful work with your company. I have a lot of skill and experience in software delivery, code craft, and team management.
Consider contracting me for a few days. I would love to help.
May 22, 2025 at 10:49 AM
I could use a nice trip to somewhere in Europe or the UK.
I'd like to sponsor my trip by doing useful work with your company. I have a lot of skill and experience in software delivery, code craft, and team management.
Consider contracting me for a few days. I would love to help.
I'd like to sponsor my trip by doing useful work with your company. I have a lot of skill and experience in software delivery, code craft, and team management.
Consider contracting me for a few days. I would love to help.
What's a good folder structure to adopt in a #typescript backend app? gist.github.com/pesterhazy/0...
What's a good folder structure to use for a Typescript backend app?
What's a good folder structure to use for a Typescript backend app? - typescript-folder-structure.md
gist.github.com
May 16, 2025 at 12:22 PM
What's a good folder structure to adopt in a #typescript backend app? gist.github.com/pesterhazy/0...
My team is hiring a Founding Engineer in Berlin (no remote) hi.telli.com/eng
founding engineer - telli
hi.telli.com
April 15, 2025 at 6:16 PM
My team is hiring a Founding Engineer in Berlin (no remote) hi.telli.com/eng
Today should a node project use ESM (rather than commonjs) and {"type": "module"}?
Just spent half a day fighting with node's module resolution and --experimental-strip-types
Just spent half a day fighting with node's module resolution and --experimental-strip-types
April 14, 2025 at 12:00 PM
Today should a node project use ESM (rather than commonjs) and {"type": "module"}?
Just spent half a day fighting with node's module resolution and --experimental-strip-types
Just spent half a day fighting with node's module resolution and --experimental-strip-types
Zod v4 is marketed as having 20x fewer instantiations of tsc...
While it's great to see progress, this news makes me hesitant to use it. Why was it doing so much in the first place? All that type-level complexity must have a cost
While it's great to see progress, this news makes me hesitant to use it. Why was it doing so much in the first place? All that type-level complexity must have a cost
April 13, 2025 at 3:04 PM
Zod v4 is marketed as having 20x fewer instantiations of tsc...
While it's great to see progress, this news makes me hesitant to use it. Why was it doing so much in the first place? All that type-level complexity must have a cost
While it's great to see progress, this news makes me hesitant to use it. Why was it doing so much in the first place? All that type-level complexity must have a cost
Logged in to Twitter, the first thing I see is this
Pathetic
Pathetic
April 13, 2025 at 2:10 PM
Logged in to Twitter, the first thing I see is this
Pathetic
Pathetic
published beep-boop 0.1.2 - audiovisual feedback for test runs
now easy to install via npm
github.com/pesterhazy/b...
now easy to install via npm
github.com/pesterhazy/b...
GitHub - pesterhazy/beep-boop: Audible and visual feedback for test runs
Audible and visual feedback for test runs. Contribute to pesterhazy/beep-boop development by creating an account on GitHub.
github.com
April 13, 2025 at 1:51 PM
published beep-boop 0.1.2 - audiovisual feedback for test runs
now easy to install via npm
github.com/pesterhazy/b...
now easy to install via npm
github.com/pesterhazy/b...
Map#getOrInsert seems useful
ECMAScript excitement 😉
TC39 will consider these JS proposals for stage movement at this week's meeting 🎉
2️⃣.7️⃣ Immutable ArrayBuffer
2️⃣ Upsert
🗑️ Record & Tuple
0️⃣ Compare strings by codepoint
0️⃣ Composite Keys
0️⃣ Disposable AsyncContext
0️⃣ Enum
0️⃣ Non-extensible applies to private
0️⃣ Object.propertyCount
TC39 will consider these JS proposals for stage movement at this week's meeting 🎉
2️⃣.7️⃣ Immutable ArrayBuffer
2️⃣ Upsert
🗑️ Record & Tuple
0️⃣ Compare strings by codepoint
0️⃣ Composite Keys
0️⃣ Disposable AsyncContext
0️⃣ Enum
0️⃣ Non-extensible applies to private
0️⃣ Object.propertyCount
April 12, 2025 at 4:40 PM
Map#getOrInsert seems useful
Reposted by Paulus Esterhazy
My new book is out: “Exploring TypeScript”. It’s free online!
• About 75% of the content is new or rewritten.
• Most of the new content is about computing at the type level.
exploringjs.com/ts/
#TypeScript
• About 75% of the content is new or rewritten.
• Most of the new content is about computing at the type level.
exploringjs.com/ts/
#TypeScript
April 10, 2025 at 6:22 PM
My new book is out: “Exploring TypeScript”. It’s free online!
• About 75% of the content is new or rewritten.
• Most of the new content is about computing at the type level.
exploringjs.com/ts/
#TypeScript
• About 75% of the content is new or rewritten.
• Most of the new content is about computing at the type level.
exploringjs.com/ts/
#TypeScript
What a wonderful finale, just as cynical as I hoped it would be
April 7, 2025 at 8:43 PM
What a wonderful finale, just as cynical as I hoped it would be
Are US tariffs going to affect digital goods like SaaS software?
April 5, 2025 at 12:40 PM
Are US tariffs going to affect digital goods like SaaS software?
Updating JS dependencies after 6 months. Nothing works
March 28, 2025 at 1:09 PM
Updating JS dependencies after 6 months. Nothing works
Of all the bad APIs I've used, Hubspot takes the crown
March 28, 2025 at 11:08 AM
Of all the bad APIs I've used, Hubspot takes the crown
Reposted by Paulus Esterhazy
Teamwork makes the dream work… Along with good architecture, agility, frequent communication (“Yes chef!”), domain driven thinking, a ton of collective experience, knowledge sharing and a lot of passion. But 10x developers? Nah. That’s just over-reliance on one point of failure.
March 27, 2025 at 11:08 PM
Teamwork makes the dream work… Along with good architecture, agility, frequent communication (“Yes chef!”), domain driven thinking, a ton of collective experience, knowledge sharing and a lot of passion. But 10x developers? Nah. That’s just over-reliance on one point of failure.
Reposted by Paulus Esterhazy
The Boston Public Library is my happy place.
March 16, 2025 at 2:14 PM
The Boston Public Library is my happy place.
In iTerm, Cmd-Shift-a copies the output of the last command executed. Not sure how I survived so long without knowing this
TIL in vim, "gx" opens the URL under your cursor in your default web browser! Also works with local file paths
March 16, 2025 at 1:51 PM
In iTerm, Cmd-Shift-a copies the output of the last command executed. Not sure how I survived so long without knowing this
Truth bomb on HN: "During ZIRP the incentives for employees were completely disconnected from the underlying business, leading to entire careers being built around and rewarded for the wrong outcomes."
March 16, 2025 at 1:37 PM
Truth bomb on HN: "During ZIRP the incentives for employees were completely disconnected from the underlying business, leading to entire careers being built around and rewarded for the wrong outcomes."
"What's the advice you would give you to your younger self?"
I must have watched this a million times. This is my favorite clip in the entire internet www.youtube.com/shorts/NGJu6...
I must have watched this a million times. This is my favorite clip in the entire internet www.youtube.com/shorts/NGJu6...
Don't spend time with your kids??
YouTube video by Business Without Bullsh-t
www.youtube.com
March 10, 2025 at 8:47 PM
"What's the advice you would give you to your younger self?"
I must have watched this a million times. This is my favorite clip in the entire internet www.youtube.com/shorts/NGJu6...
I must have watched this a million times. This is my favorite clip in the entire internet www.youtube.com/shorts/NGJu6...
I'm, *sigh*, going to get better at llm-assisted development. But I want to treat it as a tool to learn, not a short cut. Where should I start? What are the best guides, preferably from people who understand the limitations as well as the upsides?
March 9, 2025 at 12:22 PM
I'm, *sigh*, going to get better at llm-assisted development. But I want to treat it as a tool to learn, not a short cut. Where should I start? What are the best guides, preferably from people who understand the limitations as well as the upsides?
Wow, solving all SICP problems takes 729 hrs! lockywolf.wordpress.com/2021/02/08/s...
Solving SICP
This report is written as a post-mortem of a project that has, perhaps, been the author’s most extensive personal project: creating a complete and comprehensive solution to one of the most fa…
lockywolf.wordpress.com
March 4, 2025 at 9:11 PM
Wow, solving all SICP problems takes 729 hrs! lockywolf.wordpress.com/2021/02/08/s...
Reposted by Paulus Esterhazy
Instead of asking “When is all this going to be done?”, consider asking: “Why can't we release what we have now?”.
February 18, 2025 at 6:20 PM
Instead of asking “When is all this going to be done?”, consider asking: “Why can't we release what we have now?”.
I was tired of slow #Emacs lsp completions, which locked up my editor for up to 5s.
So I switched to lsp-bridge and now I don't know why I didn't try it earlier. It's so fast, so good, I want to scream it from the rooftops!
So I switched to lsp-bridge and now I don't know why I didn't try it earlier. It's so fast, so good, I want to scream it from the rooftops!
January 29, 2025 at 8:44 PM
I was tired of slow #Emacs lsp completions, which locked up my editor for up to 5s.
So I switched to lsp-bridge and now I don't know why I didn't try it earlier. It's so fast, so good, I want to scream it from the rooftops!
So I switched to lsp-bridge and now I don't know why I didn't try it earlier. It's so fast, so good, I want to scream it from the rooftops!
For the second time, in two very different jobs, I'm encountering unexpected HTTP 502 errors in a backend API.
In each case, the symptom is the reverse proxy reporting "Connection closed unexpectedly" or similar. I suspect the problem in each case to be HTTP keep-alive. Is it just me?
In each case, the symptom is the reverse proxy reporting "Connection closed unexpectedly" or similar. I suspect the problem in each case to be HTTP keep-alive. Is it just me?
January 27, 2025 at 5:35 PM
For the second time, in two very different jobs, I'm encountering unexpected HTTP 502 errors in a backend API.
In each case, the symptom is the reverse proxy reporting "Connection closed unexpectedly" or similar. I suspect the problem in each case to be HTTP keep-alive. Is it just me?
In each case, the symptom is the reverse proxy reporting "Connection closed unexpectedly" or similar. I suspect the problem in each case to be HTTP keep-alive. Is it just me?