Sylvain Wallez
@swallez.com
Software engineer, from big servers to tiny microcontrollers. Principal engineer at @elastic.co, member of @apache.org. Blogging (sometimes) at https://bluxte.net
🌐 Toulouse, France, Europe
🌐 Toulouse, France, Europe
After a short stint in a startup that didn't go as expected, I'm back at @elastic.co, joining Elasticsearch's Analytical Engine team. There's a lot of work, and I bring there — among others — my care for nice APIs and my knowledge of the Arrow ecosystem, the lingua franca of analytics systems.
January 13, 2026 at 1:22 PM
After a short stint in a startup that didn't go as expected, I'm back at @elastic.co, joining Elasticsearch's Analytical Engine team. There's a lot of work, and I bring there — among others — my care for nice APIs and my knowledge of the Arrow ecosystem, the lingua franca of analytics systems.
"Building a good API is not trivial, and focus is required. The Elasticsearch Java SDK caught my attention because it actually gets this stuff right" — I'm pretty stoked to see my work being analyzed and recognized like this 😊 javapro.io/2026/01/13/e...
JAVAPRO International Elasticsearch Java SDK: No Magic, Just Solid Design Choices -
JAVAPRO International Elasticsearch Java SDK: No Magic, Just Solid Design Choices API & Frameworks - Open Source
javapro.io
January 13, 2026 at 10:32 AM
"Building a good API is not trivial, and focus is required. The Elasticsearch Java SDK caught my attention because it actually gets this stuff right" — I'm pretty stoked to see my work being analyzed and recognized like this 😊 javapro.io/2026/01/13/e...
Reposted by Sylvain Wallez
1/3 Il y a 5 ans et demi, j'écrivais cet article. A peine une demi-décennie plus tard, de nombreuses choses sont en train de se réaliser avec l'IA, tel que je l'écrivais ⤵️
www.emaxilde.net/posts/2020/0...
www.emaxilde.net/posts/2020/0...
L'alignement de l'esprit importe plus que celui du code
Dans mon billet précédent, j’ai dressé un constat très personnel concernant l’évolution du marché de l’ingénierie informatique durant ces 25 dernières années, sur ce qu’il me semble être aujourd’hui e...
www.emaxilde.net
January 12, 2026 at 10:44 AM
1/3 Il y a 5 ans et demi, j'écrivais cet article. A peine une demi-décennie plus tard, de nombreuses choses sont en train de se réaliser avec l'IA, tel que je l'écrivais ⤵️
www.emaxilde.net/posts/2020/0...
www.emaxilde.net/posts/2020/0...
Reposted by Sylvain Wallez
Sometimes you just have to let @lopatto.bsky.social say it out loud www.theverge.com/policy/85990...
Tim Cook and Sundar Pichai are cowards
Once you’ve traded your principles for proximity to power, do you even run your own company?
www.theverge.com
January 9, 2026 at 9:29 PM
Sometimes you just have to let @lopatto.bsky.social say it out loud www.theverge.com/policy/85990...
Karateka est un des jeux auxquels j'ai le plus joué sur mon Apple II dans les années 80, et qui m'a donné le plus de sueurs froides. Merci Jordan !
En streaming gratuit sur France Télévisions jusqu’au 10 janvier : "Jordan, itinéraire d’un pionnier du jeu vidéo", documentaire de 52 minutes.📽Il retrace mon parcours de la création de jeux vidéo dans les 1980 à mes BD en France aujourd’hui. www.france.tv/documentaire...
Jordan, itinéraire d'un pionnier du jeu vidéo - Documentaire en replay La France en vrai - Occitanie
Pionnier américain du jeu vidéo, Jordan Mechner est le créateur du cultissime "Prince of Persia". Jordan raconte son parcours de surdoué, excellant dans le j...
www.france.tv
January 10, 2026 at 9:19 AM
Karateka est un des jeux auxquels j'ai le plus joué sur mon Apple II dans les années 80, et qui m'a donné le plus de sueurs froides. Merci Jordan !
Mon utilisation des LLMs pour répondre à un CFP : comme un relecteur, avec le prompt "Que penses-tu du style de cette proposition de conférence ? Suggère des améliorations s'il y a lieu, mais uniquement sur la forme". Une sorte de super correcteur grammatical. Ça reste mon texte et ma voix.
January 9, 2026 at 10:07 AM
Mon utilisation des LLMs pour répondre à un CFP : comme un relecteur, avec le prompt "Que penses-tu du style de cette proposition de conférence ? Suggère des améliorations s'il y a lieu, mais uniquement sur la forme". Une sorte de super correcteur grammatical. Ça reste mon texte et ma voix.
Reposted by Sylvain Wallez
Alan Dye, the "genius" behind Liquid Glass, is leaving Apple for Meta. Stephen Lemay is taking over. Now there's at least a little hope they might fix things.
I can already hear developers and users rejoicing.
I can already hear developers and users rejoicing.
January 9, 2026 at 9:30 AM
Alan Dye, the "genius" behind Liquid Glass, is leaving Apple for Meta. Stephen Lemay is taking over. Now there's at least a little hope they might fix things.
I can already hear developers and users rejoicing.
I can already hear developers and users rejoicing.
Running TensorFlow from Java 25 Without JNI or Python: a nice illustration of the use of FFM (foreign function and memory) in modern Java www.the-main-thread.com/p/java-25-te...
Running TensorFlow from Java 25 Without JNI or Python
How the Foreign Function & Memory API Enables Fast, Local ML Inference on macOS
www.the-main-thread.com
January 9, 2026 at 9:13 AM
Running TensorFlow from Java 25 Without JNI or Python: a nice illustration of the use of FFM (foreign function and memory) in modern Java www.the-main-thread.com/p/java-25-te...
There's most probably a nerdy Easter egg in the tempo of Daft Punk's "Harder, Better, Faster, Stronger"! (via @anaethelion.bsky.social) www.madebywindmill.com/tempi/blog/h...
Was Daft Punk Having a Laugh When They Chose the Tempo of Harder, Better, Faster, Stronger?
Was Daft Punk Having a Laugh When They Chose the Tempo of Harder, Better, Faster, Stronger?
www.madebywindmill.com
January 9, 2026 at 8:57 AM
There's most probably a nerdy Easter egg in the tempo of Daft Punk's "Harder, Better, Faster, Stronger"! (via @anaethelion.bsky.social) www.madebywindmill.com/tempi/blog/h...
Reposted by Sylvain Wallez
On parle souvent des conséquences catastrophiques de la politique sanitaire du gouvernement Trump, portée par son secrétaire à la santé complotiste et antivax Robert Kennedy Jr., à la fois aux US, mais aussi dans le reste du monde.
En voici un exemple terrifiant.
Thread à dérouler ci-dessous
1/16
En voici un exemple terrifiant.
Thread à dérouler ci-dessous
1/16
January 8, 2026 at 5:43 PM
On parle souvent des conséquences catastrophiques de la politique sanitaire du gouvernement Trump, portée par son secrétaire à la santé complotiste et antivax Robert Kennedy Jr., à la fois aux US, mais aussi dans le reste du monde.
En voici un exemple terrifiant.
Thread à dérouler ci-dessous
1/16
En voici un exemple terrifiant.
Thread à dérouler ci-dessous
1/16
My former colleague @iuliaferoli.com is taking us on her journey to learn robotics. And she's having a lot of fun! youtu.be/qnDjWk76ga4
I control this robot car only with voice and gestures! RACE CHALLENGE
YouTube video by Back to Engineering (iulia)
youtu.be
January 8, 2026 at 5:36 PM
My former colleague @iuliaferoli.com is taking us on her journey to learn robotics. And she's having a lot of fun! youtu.be/qnDjWk76ga4
Reposted by Sylvain Wallez
If you missed it, we posted a new episode of our podcast yesterday. This episode features Jean-Baptiste Kempf of
@scaleway.com. Link below:
@scaleway.com. Link below:
January 7, 2026 at 10:54 PM
If you missed it, we posted a new episode of our podcast yesterday. This episode features Jean-Baptiste Kempf of
@scaleway.com. Link below:
@scaleway.com. Link below:
Reposted by Sylvain Wallez
Jeu:
-trouvez un équivalent français fonctionnel (ça veut dire qu'on doit pouvoir l'utiliser dans une phrase!)
-trouvez un équivalent non fonctionnel qui sera proposé dans 150 ans par l'académie et que personne n'utilisera
-trouvez un équivalent français fonctionnel (ça veut dire qu'on doit pouvoir l'utiliser dans une phrase!)
-trouvez un équivalent non fonctionnel qui sera proposé dans 150 ans par l'académie et que personne n'utilisera
January 6, 2026 at 9:07 PM
Jeu:
-trouvez un équivalent français fonctionnel (ça veut dire qu'on doit pouvoir l'utiliser dans une phrase!)
-trouvez un équivalent non fonctionnel qui sera proposé dans 150 ans par l'académie et que personne n'utilisera
-trouvez un équivalent français fonctionnel (ça veut dire qu'on doit pouvoir l'utiliser dans une phrase!)
-trouvez un équivalent non fonctionnel qui sera proposé dans 150 ans par l'académie et que personne n'utilisera
"Stay curious, stay humble, and remember that the work is always about people - the users you’re building for and the teammates you’re building with". So much wisdom in these 21 lessons learned! addyosmani.com/blog/21-less...
21 Lessons From 14 Years at Google
Lessons learned from 14 years of engineering at Google, focusing on what truly matters beyond just writing great code.
addyosmani.com
January 7, 2026 at 7:43 AM
"Stay curious, stay humble, and remember that the work is always about people - the users you’re building for and the teammates you’re building with". So much wisdom in these 21 lessons learned! addyosmani.com/blog/21-less...
Reposted by Sylvain Wallez
WebAssembly is still for me one of the underestimated pieces in the IT landscape. Here a small POC, to store a WASM on RustFS and execute it on an API call. Just for fun and demonstration 🙂
github.com/oxide-byte/w...
#rustlang #webassembly #serverless
github.com/oxide-byte/w...
#rustlang #webassembly #serverless
GitHub - oxide-byte/wasm-faas: WASM-FaaS Platform for uploading WASM files to RustFS and download for executing with an API
WASM-FaaS Platform for uploading WASM files to RustFS and download for executing with an API - oxide-byte/wasm-faas
github.com
January 7, 2026 at 7:13 AM
WebAssembly is still for me one of the underestimated pieces in the IT landscape. Here a small POC, to store a WASM on RustFS and execute it on an API call. Just for fun and demonstration 🙂
github.com/oxide-byte/w...
#rustlang #webassembly #serverless
github.com/oxide-byte/w...
#rustlang #webassembly #serverless
Reposted by Sylvain Wallez
Pour ceux qui me connaissent (auteur de Bacon, Broot, dysk, etc. ainsi que de blog technique Rust), je vais être disponible pour des missions (kick-off de projet Rust, architecture, développement, formation).
Le repost aide le développeur open-source à se financer.
dystroy.org
Le repost aide le développeur open-source à se financer.
dystroy.org
dystroy
dystroy - Rust consulting
dystroy.org
January 7, 2026 at 7:15 AM
Pour ceux qui me connaissent (auteur de Bacon, Broot, dysk, etc. ainsi que de blog technique Rust), je vais être disponible pour des missions (kick-off de projet Rust, architecture, développement, formation).
Le repost aide le développeur open-source à se financer.
dystroy.org
Le repost aide le développeur open-source à se financer.
dystroy.org
Reposted by Sylvain Wallez
🐳 Docker Compose Tip #2
Same compose.yml for dev/staging/prod:
docker compose --env-file .env.dev up
docker compose --env-file .env.prod up
No more copying env vars around. Each environment gets its own file.
More: lours.me/posts/compose-tip-002-env-files/
#Docker #DockerCompose
Same compose.yml for dev/staging/prod:
docker compose --env-file .env.dev up
docker compose --env-file .env.prod up
No more copying env vars around. Each environment gets its own file.
More: lours.me/posts/compose-tip-002-env-files/
#Docker #DockerCompose
Docker Compose Tip #2: Using --env-file for different environments
How to manage dev, staging, and production configurations with env files
lours.me
January 6, 2026 at 8:23 AM
🐳 Docker Compose Tip #2
Same compose.yml for dev/staging/prod:
docker compose --env-file .env.dev up
docker compose --env-file .env.prod up
No more copying env vars around. Each environment gets its own file.
More: lours.me/posts/compose-tip-002-env-files/
#Docker #DockerCompose
Same compose.yml for dev/staging/prod:
docker compose --env-file .env.dev up
docker compose --env-file .env.prod up
No more copying env vars around. Each environment gets its own file.
More: lours.me/posts/compose-tip-002-env-files/
#Docker #DockerCompose
Reposted by Sylvain Wallez
Spinlocks vs. Mutexes: When to Spin and When to Sleep
Great introduction and explanation why sometimes wasting some CPU to spinlock is the better alternative to mutexes and sometimes it is vice versa, depending on contention.
howtech.substack.com/p/spinlocks-...
Great introduction and explanation why sometimes wasting some CPU to spinlock is the better alternative to mutexes and sometimes it is vice versa, depending on contention.
howtech.substack.com/p/spinlocks-...
Spinlocks vs. Mutexes: When to Spin and When to Sleep
You’re staring at perf top showing 60% CPU time in pthread_mutex_lock. Your latency is in the toilet. Someone suggests “just use a spinlock” and suddenly your 16-core server is pegged at 100% doing…
howtech.substack.com
January 5, 2026 at 1:56 PM
Spinlocks vs. Mutexes: When to Spin and When to Sleep
Great introduction and explanation why sometimes wasting some CPU to spinlock is the better alternative to mutexes and sometimes it is vice versa, depending on contention.
howtech.substack.com/p/spinlocks-...
Great introduction and explanation why sometimes wasting some CPU to spinlock is the better alternative to mutexes and sometimes it is vice versa, depending on contention.
howtech.substack.com/p/spinlocks-...
Hacking washing machines (and other home appliances). We have a number of B/S/H appliances (Bosch & Siemens), and now I want to plug an ESP32 on their D-Bus 😅 youtu.be/Q1S-PVo3GlA
39C3 - Hacking washing machines
YouTube video by media.ccc.de
youtu.be
January 4, 2026 at 1:06 PM
Hacking washing machines (and other home appliances). We have a number of B/S/H appliances (Bosch & Siemens), and now I want to plug an ESP32 on their D-Bus 😅 youtu.be/Q1S-PVo3GlA
Reposted by Sylvain Wallez
Et bonne année ! et pour commencer, on va explorer un petit mode de calcul qui échappe à beaucoup de gens (même certains pros...) derrière qui je repasse régulièrement.
Le calcul des sections de câbles, j'ai souvent ces cas là (exemple sur une alimentation sur un pulvérisateur)
Le calcul des sections de câbles, j'ai souvent ces cas là (exemple sur une alimentation sur un pulvérisateur)
January 4, 2026 at 11:39 AM
Et bonne année ! et pour commencer, on va explorer un petit mode de calcul qui échappe à beaucoup de gens (même certains pros...) derrière qui je repasse régulièrement.
Le calcul des sections de câbles, j'ai souvent ces cas là (exemple sur une alimentation sur un pulvérisateur)
Le calcul des sections de câbles, j'ai souvent ces cas là (exemple sur une alimentation sur un pulvérisateur)
Reposted by Sylvain Wallez
Further Optimizing my Java SwissTable: Profile Pollution and SWAR Probing
second part of an awesome blog post improving performance via profiling and lots of prior knowledge that I do not have. Great read!
bluuewhale.github.io/posts/furthe...
second part of an awesome blog post improving performance via profiling and lots of prior knowledge that I do not have. Great read!
bluuewhale.github.io/posts/furthe...
Further Optimizing my Java SwissTable: Profile Pollution and SWAR Probing
A second round of Java SwissTable tuning: why Objects.equals polluted the profile, and why a SWAR probing loop beat the Vector API on ARM and x86.
bluuewhale.github.io
January 3, 2026 at 1:56 PM
Further Optimizing my Java SwissTable: Profile Pollution and SWAR Probing
second part of an awesome blog post improving performance via profiling and lots of prior knowledge that I do not have. Great read!
bluuewhale.github.io/posts/furthe...
second part of an awesome blog post improving performance via profiling and lots of prior knowledge that I do not have. Great read!
bluuewhale.github.io/posts/furthe...
Nice explanation of a major benefit of wide events over regular structured logging: it allows tail sampling, i.e. store rich data for every problematic request while sampling successful requests which aren't those you'll want to search for. Although this means you cannot derive metrics from events…
Logging Sucks - Your Logs Are Lying To You
Why traditional logging fails and how wide events can fix your observability
loggingsucks.com
January 3, 2026 at 8:45 AM
Nice explanation of a major benefit of wide events over regular structured logging: it allows tail sampling, i.e. store rich data for every problematic request while sampling successful requests which aren't those you'll want to search for. Although this means you cannot derive metrics from events…
Hey @pier.fumagalli.org! Someone from your family? 🍝
went back and grabbed the full video of her intro. absolutely incredible
🇮🇹🍝👩🍳🤌🇮🇹🍝👩🍳🤌🇮🇹🍝👩🍳🤌🇮🇹🍝👩🍳🤌
🇮🇹🍝👩🍳🤌🇮🇹🍝👩🍳🤌🇮🇹🍝👩🍳🤌🇮🇹🍝👩🍳🤌
January 2, 2026 at 6:31 PM
Hey @pier.fumagalli.org! Someone from your family? 🍝
Happy new year! Beyond the mandatory celebration, it's also a reminder that there are a lot of good things happening every year, even if we have the feeling of drowning in the bad news and disasters. Let's not forget these good things!
a man with a mustache is sitting at a table with two other people and says happy new year .
Alt: a man with a mustache is sitting at a table with two other people and says happy new year .
media.tenor.com
January 1, 2026 at 9:27 AM
Happy new year! Beyond the mandatory celebration, it's also a reminder that there are a lot of good things happening every year, even if we have the feeling of drowning in the bad news and disasters. Let's not forget these good things!
Reposted by Sylvain Wallez
Data plumbing has never mattered more. From the maturation of open standards like ADBC and Iceberg to the infrastructure needed for agentic workflows, here are our 10 predictions for 2026 🔮
columnar.tech/blog/2026-pr...
columnar.tech/blog/2026-pr...
10 Predictions for Data Infrastructure in 2026
What we see coming in the year ahead
columnar.tech
December 31, 2025 at 3:31 PM
Data plumbing has never mattered more. From the maturation of open standards like ADBC and Iceberg to the infrastructure needed for agentic workflows, here are our 10 predictions for 2026 🔮
columnar.tech/blog/2026-pr...
columnar.tech/blog/2026-pr...