Julien Codorniou

Announcing Slashwork.com, backed/incubated by @20vcFund and the very people who built Slack and Workplace. Proudly built in London. 🇬🇧

One of my favorite things about starting ArchAstro and building a cross-company, multiplayer agentic harness is that it gives me an excuse to collaborate with all of my favorite people who have since moved on from BigTech to join startups or be solo builders.

You probably used @FireworksAI_HQ this week. The cool part is that you just did not know you did. 🎆 Open-source models are free, sure... but the hard part is tailoring them so they perform best on your own use cases. And making them run fast, cheaply, and reliably in production. This is the mega hard work. *Fireworks is the layer that does this exact work:* it sits above the chips, but below the model, abstracting away the complexity of deploying and optimising open models. As a result, they already crossed >$1bn in run-rate revenue, up 5x YoY... and they are accelerating at scale! 20VC invested $10m in the most recent round. Here is why @HarryStebbings and I at @20vcFund were excited to do so: *First, the team:* the company was founded in 2022 by @lqiao and six co-founders, largely the team that built and ran PyTorch (the framework nearly every AI model on earth is trained on) at Meta. That is truly a unique right to win in that space: if anyone knows how to make models run fast on GPUs, it is the Fireworks team. *Second, what they do:* the best analogy I can come up with is Formula 1. Models are the engine, and Fireworks is the race team (prep, pit crew, strategy, and fine tuning of the car). You can have the best engine, but without the best race team, you are not winning. 🥇 *So how does it work in practice?* Two options: (1) You just pick an open model off the shelf (DeepSeek, Kimi, Llama, gpt-oss...) from the 400+ already running on their platform, you call the API, and you pay per token. You do not need to rent GPUs or manage clusters: their hand-written GPU code (down to the kernel level!) runs those models. And they do so faster and cheaper than you could yourself. Or, and most importantly (2) when off-the-shelf is not enough, they help you fine-tune an open model on your own data. With that: a specialist model, at a fraction of the cost, will beat a frontier generalist on your specific tasks. That approach is available self serve on their platform, or, for large customers - through FDEs who work directly with them to optimise models for their specific workloads. That is, in part, how @cursor_ai built its Composer model: on Fireworks. Similarly, @harvey achieved above frontier performance at 10% of the cost (yes, that's mindblowing) working hand in hand with the Fireworks AI teams. *And why will they win, structurally:* (a) inference is where the money is going: ~90% of a model's lifetime compute is spent running it (as opposed to training it). And agentic AI is a driving force behind the explosion in token volumes ==> the tide rises fastest where Fireworks sits, and I think this mega-trend will continue working in their favour (b) open models have reached near-frontier quality ==> every CFO is starting to worry about their closed-model API bill. And now Fireworks enables them to off-ramp from that exponential cost scaling: they can continue performing at frontier level (or above!), but at 10% of the cost (c) speed: per @ArtificialAnlys (independent benchmarks), Fireworks is consistently the fastest GPU-based provider on top open models. Only the custom-silicon players beat them on raw speed - but often at higher costs and with a fraction of the model coverage (d) no lock-in: CEOs and CTOs do not want vendor lock-in given how fast the space moves. DeepSeek beats Kimi, Kimi beats Llama, Llama beats DeepSeek again... It does not matter: Fireworks earns on all of them. Model churn benefits Fireworks. *I also reviewed 20 expert calls. Four observations stood out:* 1) one head of AI rated their support "14 out of 10". And no, that is not a typo! He added they would be "much worse off without them" 2) one customer moved a flagship AI feature off GPT-4o onto an open model on Fireworks: 70-80% cheaper... and usage went UP 20% (👋 Jevons Paradox) 3) a global creative-software giant scored them 9/10 head-to-head vs 7 for their closest rival, and is shifting more towards Fireworks as a result 4) a top-5 US healthcare company, asked to pick one inference provider to bet on: "I would go with Fireworks" When Cursor writes your code, when Notion's AI summarises your meeting, when Upwork drafts a freelancer's proposal... they share the same engine underneath: Fireworks AI. The winning layer may not be the model itself, but the infrastructure that makes every open model usable. Great infrastructure companies are invisible to users, but indispensable to developers! Let's go Lin and Fireworks team 🚀 cc. Harry Stebbings, @Kieranleehill, @codorniou, @alexandre_dewez, @NiallKiely20VC

@hthieblot Winamp and Napster

Anyone who surfed the early web between 1995-2010. What’s the one website/app you still think about?

Saudades da minha família

👀👀

ArchAstro is a place where we all build and maintain the tools we need to do our day to day work. It feels really empowering to be able to say "our build/dev/deploy/review/infra/etc system doesn't work the way I want it to, let me make a change" We're starting to open source this stuff too

Nothing makes me happier than to be working on the same team as OG Tweep _and_ OG @stripe @kurrik. And we added one more DAU to X as a side effect.

1/ Wanted to share a bit about my agentic setup. At ArchAstro, we do all our development locally on Mac (local services/DB) and so my workflow is designed around maximizing productivity for local dev. (I would love to move some to cloud, more on that another time).

L’histoire magnifique de Smaïl Zidane, le papa de Zinedine. Le destin 💫

👀

@SlashworkApp 🚀🤞👀

@hthieblot Async work FTW

Pitch me your company in 3 words.

1/ Wanted to formally say hello on X! I'm an ex-Big-tech VP returning to full-time builder. And yeah, I’m loving every second of it. After years mostly lurking here, I’m finally posting properly. I’m a founder at ArchAstro. Here’s the short version of how I got here.

🗣️Marc Cucurella: I have lost sleep over what happened in the World Cup final. Even after several nights, I still feel deeply disappointed by what I experienced with Leo Messi. I cannot imagine putting another player in that kind of situation, and that moment has stayed with me ever since. What hurt me the most was this: I explained to Leo Messi that Cubarsí had injured his mouth and he quickly rushed to the referee that I threw a racist insult on him which was false and demanded a red card should be given to me, Whether it was a misunderstanding or something else, the incident left me feeling unfairly judged and completely changed the way I viewed Messi. For a player of his stature, I expected a higher standard of sportsmanship. That experience also made me question many of the claims and debates I have seen online about Argentina and football’s biggest tournaments. I cannot say what is true, but it left me with doubts. For me, winning should never come at the expense of honesty, respect, and integrity. Those values are what make football truly great. Cristiano Ronaldo has been my idol since I was a child, and nothing has changed that. His discipline, mentality, consistency, and relentless work ethic are the qualities that inspire me every single day. To me, his legacy is built on dedication, perseverance, and earning success through hard work. That is why Cristiano Ronaldo will always be my greatest football inspiration.

Proust in the age of TikTok ft.com/content/511635…

@marcklingen @stratechery I still think a gateway or router should stay neutral

@SlashworkApp is hiring! 🚀 We're looking for our first commercial hire: a founding BDR to help us manage the demand we have, close our first large deals, and turn our community of customers into a cult. You'll own the whole cycle: qualifying inbound, running demos, closing deals, and onboarding customers. You'll be working side by side with founders & engineers who have built products used by billions of people to bring the magic of asynchronous work/comms to the world. We're looking for someone with 2/3 years in software sales, a "play-to-win" mindset, and genuine curiosity about the product. Full-time, in our central London office. slashwork.com/jobs/founding-…

I wanted to write about why the world (of work) needs asynchronous communication and what we're building at @SlashworkApp but our friend and investor @ceverson makes the case beautifully on the Lead Human podcast. 🚀

Vous voulez devenir #riche ? Ma formation est faite pour vous