MarsBased

Pieter Levels (@levelsio) has a habit of confidently misreading data and treating anecdotes as evidence 🧵👇 This is what happens when you train your AI and your following base with skewed world views, dodgy studies and huge biases: they amplify your crooked narrative.

Every chapter has an end. It's time to sunset StartupsBCN, the Slack community we started 11 years ago. At its peak, it was the online place to be in Barcelona, with thousands of members and many communities, events, coworking spaces curating their people and their content in StartupsBCN. In the recent years, it petered out and died a long, slow death. We could've done better, but we're grateful for everyone we've met through this community, the bonds it has created and... even families, in some cases! Full details here, on the @MarsBased podcast: youtube.com/watch?v=0FDLmtOc…

Os traigo el nuevo episodio del podcast de @MarsBased, con @martin_vigo, donde nerdeamos sobre el estado actual de la cyberseguridad, los avances de este sector en materia de IA y por qué la mejor defensa puede ser un buen ataque. ¡No os lo perdáis! youtube.com/watch?v=IHNuqcwM…

🚀 @MarsBased has never had one gigantic fuck-up that almost killed the company. No near-shutdowns, no layoffs, no steps back. Why? no investors, no external shareholders. And years of profitability that gave us cash reserves and optionality.

We're less than 3 years away from @MarsBased turning 15 years old. 🤯

Today, I'm sharing yet another fantastic blog post written by our own Anna Vidal for the @MarsBased blog.

Eleven years ago, we created a Slack community for entrepreneurs and tech people in Barcelona. It started as a platform to bridge the gap between Startup Grind Barcelona events but it soon became event agnostic, and was home to other communities and even some coworking spaces ran their private community on it, too. We called it StartupsBCN. Quite an imagination! On October 1st, I am stepping down as its host. The honest version: our focus has moved elsewhere, and this community deserves someone who is actually present in it. It has been quiet for a long time and that is on me. Also, most interactions happen in private, so there's no point in keeping channels at all, then. @MarsBased is now 30 people strong and it demands a strong focus on my side. We're riding the AI wave strongly and we're extremely excited to lead the way for other companies to follow. We've been passing the baton of other community projects like Startup Digest or Startup Grind, and now it's time for us to let go of this Slack community. What did happen, over eleven years: hires, clients, co-founders, lots of meetups, funding intros and a fair lot of friendships. That was the entire point, and it worked more often than these things usually do. We are handing this community over to members who still use it, and I will name them in a couple of weeks. Thank you for the eleven years 🤘

Following up on our previous article about how to run performance reviews using AI, this one expands on what works well and what doesn't. Read it here: marsbased.com/blog/2026/09/0… on the @marsbased blog

Our CTO @xavier_redo has now "all my Slack notifications turned off except for DMs and explicit mentions". Why? He uses Claude Cowork like a champ: marsbased.com/blog/2026/07/0…

There are sentences that end up burnt into your brain and stay for life. Almost ten years ago @piratecto described @MarsBased as "expensive but good, which is not the same as good but expensive" and I can't find a better way to describe our company. Hard to beat this claim.

Yet another former client of @MarsBased gets acquired. My heartfelt congrats to our friends @restb_ai 🤘 clearcapital.com/clear-capit…

Esta semana os traemos a @albertobeta (co-fundador de @rss y ex-CTO de Telefonica Alpha, Koa Health y Badi), para un Road to CTO muy especial.