David Sancho
@david.sancho.dev
Open Source UI infra at @ahrefs.bsky.social with OCaml
Made styled-ppx and server-reason-react
Working on reason-react / Melange / Reason
Made styled-ppx and server-reason-react
Working on reason-react / Melange / Reason
Pinned
David Sancho
@david.sancho.dev
· Oct 25
I'm david. Software dev. Can't shut up. I have problems writing in English and didn't get a proper education. I speak to fast, in spanish probably faster.
Love OCaml, prefer Reason. enjoy React, CSS, and the frontend part of my job. Wrote a CSS parser and a CSS type-checker.
Love OCaml, prefer Reason. enjoy React, CSS, and the frontend part of my job. Wrote a CSS parser and a CSS type-checker.
The future of programming: same as poker players with 24 tables at the same time, but with agents
November 12, 2025 at 11:00 AM
The future of programming: same as poker players with 24 tables at the same time, but with agents
que mierda?
November 9, 2025 at 10:37 AM
que mierda?
Reposted by David Sancho
exciting updates in the OCaml platform this month! OCaml 5.4.0 released with labelled tuples, immutable arrays, and atomic record fields 🔥 plus a new security team was established. what features are you most excited to try? 🐫
November 6, 2025 at 9:26 PM
exciting updates in the OCaml platform this month! OCaml 5.4.0 released with labelled tuples, immutable arrays, and atomic record fields 🔥 plus a new security team was established. what features are you most excited to try? 🐫
learn OCaml, go into debt if you have to
(debt here is to suffer with a package manager and build system issues. LSP is the goat)
(debt here is to suffer with a package manager and build system issues. LSP is the goat)
November 5, 2025 at 4:59 PM
learn OCaml, go into debt if you have to
(debt here is to suffer with a package manager and build system issues. LSP is the goat)
(debt here is to suffer with a package manager and build system issues. LSP is the goat)
I have only 2 ways of working with AI now
- non-stop 15 hours, 6 projects at the time, while watching LoL worlds and being x10 productive and forgetting to eat/rest/everything
- constantly getting distracted because llms made programming no fun
- non-stop 15 hours, 6 projects at the time, while watching LoL worlds and being x10 productive and forgetting to eat/rest/everything
- constantly getting distracted because llms made programming no fun
November 4, 2025 at 11:43 AM
I have only 2 ways of working with AI now
- non-stop 15 hours, 6 projects at the time, while watching LoL worlds and being x10 productive and forgetting to eat/rest/everything
- constantly getting distracted because llms made programming no fun
- non-stop 15 hours, 6 projects at the time, while watching LoL worlds and being x10 productive and forgetting to eat/rest/everything
- constantly getting distracted because llms made programming no fun
Looking forward to next days for the OCaml and ML workshop @icfp_conference
October 15, 2025 at 5:57 PM
Looking forward to next days for the OCaml and ML workshop @icfp_conference
every great product has a gambling system, which is why I feel the endorphins from CI yoloing
October 15, 2025 at 12:46 PM
every great product has a gambling system, which is why I feel the endorphins from CI yoloing
Day 2 of hacking before ICFP
Finally finished odoc markdown backend support in dune, it should make release nicer documentation sites (docusaurus, vitepress, etc) or even github itself
Before (odoc html) After (odoc to markdown |> vitepress)
Finally finished odoc markdown backend support in dune, it should make release nicer documentation sites (docusaurus, vitepress, etc) or even github itself
Before (odoc html) After (odoc to markdown |> vitepress)
October 15, 2025 at 12:07 PM
Day 2 of hacking before ICFP
Finally finished odoc markdown backend support in dune, it should make release nicer documentation sites (docusaurus, vitepress, etc) or even github itself
Before (odoc html) After (odoc to markdown |> vitepress)
Finally finished odoc markdown backend support in dune, it should make release nicer documentation sites (docusaurus, vitepress, etc) or even github itself
Before (odoc html) After (odoc to markdown |> vitepress)
Day 1 of hacking before ICFP! 🐫
Releasing opam packages used to take me ~1 hour each time. So I automated it.
Now? On each new git tag → dune-release-action does everything (GitHub release + opam-repository PR).
Please use it and report issues github.com/davesnx/dun...
Releasing opam packages used to take me ~1 hour each time. So I automated it.
Now? On each new git tag → dune-release-action does everything (GitHub release + opam-repository PR).
Please use it and report issues github.com/davesnx/dun...
October 14, 2025 at 4:03 PM
Day 1 of hacking before ICFP! 🐫
Releasing opam packages used to take me ~1 hour each time. So I automated it.
Now? On each new git tag → dune-release-action does everything (GitHub release + opam-repository PR).
Please use it and report issues github.com/davesnx/dun...
Releasing opam packages used to take me ~1 hour each time. So I automated it.
Now? On each new git tag → dune-release-action does everything (GitHub release + opam-repository PR).
Please use it and report issues github.com/davesnx/dun...
just landed in Singapore after 16h on a plane
second time here, this week is @icfp_conference. If you see me, come say hi.
also, any coffee recommendations?
second time here, this week is @icfp_conference. If you see me, come say hi.
also, any coffee recommendations?
October 12, 2025 at 1:40 PM
just landed in Singapore after 16h on a plane
second time here, this week is @icfp_conference. If you see me, come say hi.
also, any coffee recommendations?
second time here, this week is @icfp_conference. If you see me, come say hi.
also, any coffee recommendations?
react compiler is the same as flambda in ocaml
wowzers
wowzers
i think the @react.dev Compiler team could include more of this type of messaging. i'm being a bit inflammatory here (and Haskell may not the best analogy), but the principle of "pure things are safe to move around" is fundamentally simple and has been known for decades. teach it to new generation!
October 11, 2025 at 5:01 PM
react compiler is the same as flambda in ocaml
wowzers
wowzers
github needs a spam PR filter right now. This is beyond ridiculous (and happens every month)
October 11, 2025 at 1:41 PM
github needs a spam PR filter right now. This is beyond ridiculous (and happens every month)
when Ruby devs are interested in OCaml, it's over, we are mainstream af
October 10, 2025 at 10:01 AM
when Ruby devs are interested in OCaml, it's over, we are mainstream af
Singularity, please don't take over yet, I'm finishing CSS extraction.
The css output is still not atomic, which is essential for composition and it matters a lot for big sites!
The css output is still not atomic, which is essential for composition and it matters a lot for big sites!
October 9, 2025 at 4:03 PM
Singularity, please don't take over yet, I'm finishing CSS extraction.
The css output is still not atomic, which is essential for composition and it matters a lot for big sites!
The css output is still not atomic, which is essential for composition and it matters a lot for big sites!
reason-react mentioned lets gooo
oh wait, no
oh wait, no
the main reason react got open sourced at all, and then stayed maintained (not just “throw code over the wall” style) is because everybody working on it knew they don’t want to reinvent it from scratch at their next job
October 8, 2025 at 9:43 PM
reason-react mentioned lets gooo
oh wait, no
oh wait, no
CSS extraction is the last feature I want to implement into styled-ppx. Aside from CSS support enhancements and small refactors.
I would consider it done, or at least 1.0.0
I would consider it done, or at least 1.0.0
October 8, 2025 at 4:04 PM
CSS extraction is the last feature I want to implement into styled-ppx. Aside from CSS support enhancements and small refactors.
I would consider it done, or at least 1.0.0
I would consider it done, or at least 1.0.0
` tech debt ´ is the best-described concept in software engineering
You’re literally creating debt with every keystroke. Sometimes it accelerates delivery, sometimes it mortgages your future.
You’re literally creating debt with every keystroke. Sometimes it accelerates delivery, sometimes it mortgages your future.
October 7, 2025 at 9:56 AM
` tech debt ´ is the best-described concept in software engineering
You’re literally creating debt with every keystroke. Sometimes it accelerates delivery, sometimes it mortgages your future.
You’re literally creating debt with every keystroke. Sometimes it accelerates delivery, sometimes it mortgages your future.
writing CSS syntax is the best feature of styled-ppx, by far.
October 6, 2025 at 3:58 PM
writing CSS syntax is the best feature of styled-ppx, by far.
I'm a big fan of React. Nearly a decade of frontend dominance. Amazing patterns, backward compatibility, and measured development pace.
Nobody gets fired for picking React; it feels mature, yet it still feels experimental. I love that.
Nobody gets fired for picking React; it feels mature, yet it still feels experimental. I love that.
October 5, 2025 at 6:05 PM
I'm a big fan of React. Nearly a decade of frontend dominance. Amazing patterns, backward compatibility, and measured development pace.
Nobody gets fired for picking React; it feels mature, yet it still feels experimental. I love that.
Nobody gets fired for picking React; it feels mature, yet it still feels experimental. I love that.
One week until ICFP ✨ (in Singapore this year, btw)
Super excited. My 4th time attending (and a bunch of the ahrefs crew will be there too)
Should I organize a chill-run through the city?
Super excited. My 4th time attending (and a bunch of the ahrefs crew will be there too)
Should I organize a chill-run through the city?
October 5, 2025 at 9:39 AM
One week until ICFP ✨ (in Singapore this year, btw)
Super excited. My 4th time attending (and a bunch of the ahrefs crew will be there too)
Should I organize a chill-run through the city?
Super excited. My 4th time attending (and a bunch of the ahrefs crew will be there too)
Should I organize a chill-run through the city?
I'm discussing with LLMs about styled-ppx's type-checker and the mf it's telling me that I need to implement type synthesis from bidirectional type-checking
```
Γ ⊢ e₁ ⇒ τ₁ → τ₂ Γ ⊢ e₂ ⇐ τ₁
─────────────
Γ ⊢ e₁ e₂ ⇒ τ₂
```
tbh, it doesn't sound alien to me. Let me get my thoughts out
```
Γ ⊢ e₁ ⇒ τ₁ → τ₂ Γ ⊢ e₂ ⇐ τ₁
─────────────
Γ ⊢ e₁ e₂ ⇒ τ₂
```
tbh, it doesn't sound alien to me. Let me get my thoughts out
October 2, 2025 at 1:16 PM
I'm discussing with LLMs about styled-ppx's type-checker and the mf it's telling me that I need to implement type synthesis from bidirectional type-checking
```
Γ ⊢ e₁ ⇒ τ₁ → τ₂ Γ ⊢ e₂ ⇐ τ₁
─────────────
Γ ⊢ e₁ e₂ ⇒ τ₂
```
tbh, it doesn't sound alien to me. Let me get my thoughts out
```
Γ ⊢ e₁ ⇒ τ₁ → τ₂ Γ ⊢ e₂ ⇐ τ₁
─────────────
Γ ⊢ e₁ e₂ ⇒ τ₂
```
tbh, it doesn't sound alien to me. Let me get my thoughts out
Reposted by David Sancho
We have done an update on the Ahrefs industrial success story here:
ocaml.org/success-stor... 🧡🐫
now there's a little more context
ocaml.org/success-stor... 🧡🐫
now there's a little more context
Petabyte-Scale Web Crawling and Data Processing · Success Stories
Ahrefs built the world's third-largest web crawler using OCaml, indexing petabytes of web data with a lean, efficient team.
ocaml.org
October 2, 2025 at 11:15 AM
We have done an update on the Ahrefs industrial success story here:
ocaml.org/success-stor... 🧡🐫
now there's a little more context
ocaml.org/success-stor... 🧡🐫
now there's a little more context
Reposted by David Sancho
Nobody even works here. It's just me and 29 advanced AIs.
October 1, 2025 at 7:22 AM
Nobody even works here. It's just me and 29 advanced AIs.