Teo Ruiz on teoruiz.com

Now

Mon, 07 Apr 2025 10:27:44 +0200

Google For Startups Campus, Madrid.

Leica Q3 | ƒ/6.30 | 1/320s | ISO 100

Resurrecting my site

I’ve been wanting to resurrect my site and blog more frequently for a while now, especially since I’ve mostly stopped using social networks.

I was waiting to have some posts or notes content, but that might take some time. So I’m starting with this, my first “Now” page and an “Uses” page.

Vernon / Fenneth

At Vernon, I have been working on our Product Studio, Fenneth.
I am basically working full-time on Dripddit, our first business. My days are filled with PydanticAI (as well as OpenAI and Anthropic APIs), Django, Shopify, and SEO—and I haven’t been happier at work in a long, long time.
I still spend some time consulting for clients, and I am really looking forward to a tech due diligence project I’ll be working on at the end of the month. Really interesting AI company doing hard work.

Reading, watching, misc.

This is month 4 since I basically stopped consuming social networks. I uninstalled Instagram, Twitter, LinkedIn, YouTube back in December. It was going to be only for a month but when that passed I just didn’t need to reinstall them. Somehow YouTube’s algorithm still kidnaps my brain through the browser though.
I subscribed to The Economist a couple of months ago, with the goal of reading long form but still current-ish news coverage. Unfortunately the weeklies are just piling up because I just don’t find the energy to read about the current state of the world.
Currently watching The White Lotus S03 and The Pitt, excruciatingly waiting for a new episode every week.
I am reading the first book in the Blackwater series, The Flood. Great escapist literature and the writing is superb, even translated into Spanish.
I have been pretty steadily going to the gym twice a week with my personal trainer, barely skipping any sessions. My body and my mind are happier than ever.

The staff I use

Wed, 02 Apr 2025 00:00:00 +0000

Tangible

iPhone 14 Pro: 512GB model from 2022 that I have a not-so-healthy dependency on.
- My first iPhone was the iPhone 5 and, even if I tried Android for a little while, the vertically integrated, walled garden experience is just smoother.
- I tend to change iPhones every 3 years, so I guess 2025 is upgrade year. Let’s see what they come up with in September.
Macbook Pro 14" M1 Pro: I spend most of my non-sleeping hours on this beautiful thing.
- It’s just an amazing programming workstation. Even as a CTO or consultant, I still spend a lot of time programming, and the MBP never gets in the way — it just works.
- Even with the 2021 version, I never feel like I’m waiting on it. Only recently, with 60-megapixel DNG files in Lightroom, did I start thinking about upgrading.
- The ARM-based Mac chips are a real leap in performance and efficiency. I can’t see myself choosing a different architecture.
- I usually carry a 65W USB-C Anker 735 charging brick when I’m working out of home. Having two USB-C and one USB-A port is terribly convenient.
Leica Q3: Most of the photos on this site are and will be shot with a Leica Q3, which I got last summer.
- I know a camera doesn’t make a better photographer, but I really enjoy shooting with it.
- Full-frame, with a gorgeous fixed Summilux-M 28 mm f/1.7 ASPH lens. The clarity, the sharpness, the colors — everything is just right.
Kindle: My first Kindle was the classic Kindle 3 with a keyboard, back in 2010.
- I upgraded to a Kindle Voyage in 2014 and read a lot on it — I have this vivid memories of late nights reading Liu Cixin’s Three-Body Problem trilogy during lockdown.
- Recently, I got the Kindle Paperwhite Signature and re-read the LOTR trilogy as its first run. The UX and responsiveness improvements, compounded over the years are very noticeable.
Other Apple gear:
- AirPods Pro 2: Besides my glasses, this is probably the object that’s most frequently on me. What would I do without its noise cancellation?
- Apple Watch Series 6: Mechanical watches have gradually taken over as my daily wristwear, but the 2020 Apple Watch is still my go-to for gym days and sleep tracking.

Intangible

Cursor: I concede: Cursor is the best coding experience I’ve ever had.
- I started my career in 2002, so I’ve gone through the full arc — a long Vim phase (I even used Mutt for email), then years of JetBrains IDEs, then VS Code with GitHub Copilot.
- Cursor convinced me to switch. It’s the best LLM-assisted programming environment out there, and it’s built on top of one of the best software packages in recent memory: VS Code.
Terminal suite: I’m not obsessive about dotfiles, but I do have a set of terminal tools I like and stick with.
- iTerm2: Been using it for years with default settings. It uses the JetBrains Mono font, which I occasionally tweak.
- Zsh: With oh-my-zsh. Marginally better than bash, but mainstream enough that everything works so it’s worth it.
- Tmux: I use it mostly for remote sessions. Switched from GNU Screen years ago, and still have Ctrl-A and Ctrl-B fighting for dominance.
Mac apps:
- Browsers:
  - Chrome: I use Chrome mostly for work — multiple profiles, great dev tools, reliable console. Not my default, but always close at hand.
  - Safari: My default browser on macOS. Light, fast, and well integrated. I use it for email and general browsing.
  - Firefox: My choice when interacting with Spanish government websites or using digital certificates. It’s been the most consistent option over time.
- Spark Desktop: My daily email client across all accounts. I like that it’s made by a small European company. I used Superhuman briefly, but Spark ended up being a better fit (i.e. cheaper). I’m less convinced by their recent AI features — they’re not very reliable yet.
- Discord: We use it at Vernon as our team chat. It’s free, the API is flexible, and it works well for our needs.
- Obsidian: My notes system. I keep client notes, research, weeklies, dailies — everything. It’s one of the tools I rely on the most.
- iA Writer: A focused Markdown writing app. Clean, minimal, and good for staying close to the text.
- iA Presenter: Write your presentations in Markdown, and get clean, readable slides. I’ve also been exploring ways to generate presentations automatically using LLMs — maybe something I’ll write about later.
- Adobe Lightroom CC: The best photo editing tool I’ve used. Cloud syncing works smoothly across devices, and the mobile app is excellent. I don’t love Adobe, but Lightroom continues to deliver.

Dev stack

Python: The core of my developer toolkit. I’ve had the dubious pleasure of working with PHP, Ruby, and more recently Go (which I really like), but I always come back to Python. It’s where I’m most fluent, and the ecosystem is everything I need — especially now that the AI stack is built around it.
Django: “The web framework for perfectionists with deadlines” is a tagline that fits. I’ve built startups and client projects with Django, and the model layer and admin (with Unfold) make me really productive.
PydanticAI: A framework from the creators of Pydantic, tailored to building AI agents. I use it in recent projects with Vernon. The validation layer is great for controlling LLM responses, and I appreciate how easy it is to swap models or run evaluations with minimal changes.
Postgres: My database of choice for two decades. Reliable, performant, and deeply familiar. I can’t think of a better general-purpose database.
Tailwind: CSS has never been my thing, but Tailwind makes it manageable. Combined with DaisyUI, it’s now my default approach for front-end work.
HTMX: A lightweight way to bring interactivity into Django apps without going full SPA. It plays really well with backend-first workflows and helps keep things simple.

Services

ChatGPT: I use ChatGPT for everything from rewording and data processing to outlining and idea generation. I also use the mobile app’s voice transcription feature — I speak, it transcribes, and that becomes the input. In fact, this whole list started that way.
OpenAI APIs: I use OpenAI’s APIs in most of my recent AI work, often with PydanticAI. They’re the most stable and well-documented tools available right now. I’m constantly surprised by how much we can now do through a single endpoint.
WeWork: I use WeWork occasionally when I need a change of environment. My Revolut plan includes a few free passes each month, and I take advantage of them when needed.

About me

Fri, 28 Mar 2025 00:00:00 +0000

My name is Teo Ruiz. I am a software engineer, CTO, and entrepreneur. I’ve been building software products for 25 years.

I was born on a random afternoon in November 1983 in southern Spain, and since then I’ve been, essentially, learning. I currently live in Madrid.

In Sevilla, my hometown.

iPhone 14 Pro | ƒ/1.90 | 1/55s | ISO 320

Projects

Over the past ~25 years, I’ve been lucky enough to work on great projects with great people:

I co-maintained a Debian-based distribution (while being an official Debian maintainer).
I was the first employee, founding member of the engineering team, and VP of Engineering at FON.
I managed the web development team at El País, one of the biggest newspapers in Spain.
I was CTO at Busuu, the world’s largest language learning startup by number of users.
I headed the engineering team at Lyst in London.
I was VP of Engineering at Jobandtalent.
For five years, I was a Co-Founder at Circular. We tried to fix the recruiting problem for candidate-driven industries, starting with tech and product recruiting for startups. We sold the company to Sngular in 2024.
I was a Co-Founder at Vernon, helping tech companies build software and digital products.
I’m now a Founder at 2701 Labs, an applied AI and engineering studio building agent-native systems and model infrastructure.

You can see my full CV and contact me on LinkedIn.

Interests

In tech, I like free software (free as in free speech), DevOps, systems and infrastructure engineering (especially on AWS and GCP), scalability, databases, automation, coding for fun and profit, the startup scene, and in general being geeky about technical things.

In Real Life, I like music, music, music, and then some other stuff (randomly sorted, ridiculously non-comprehensive list): writing, traveling, politics, quality alcoholic beverages, coffee, hanging out with my friends, food, photography, economics, reading, movies, and running.

Languages and writing

Spanish is my mother tongue, but I have a crush on the English language, so some of the posts on this old blog were written (some would say committed) in that language. Please bear with me.

Python is my preferred language for everything else, although I’ve had the doubtful pleasure of working with PHP for a few years. The Go language has recently risen to the top of my toolbox ranking, and I try to use it for new projects.

Copyleft

Text, images, and other content are licensed under a Creative Commons License, unless noted otherwise.

GPG Keys

Sun, 28 Feb 2010 00:00:00 +0000

If you want to contact me, you can encrypt your email using one of these GPG keys, which are also verified on Keybase:

New key created on 2013-09-14. Key ID: `0x4ECA7C8F`

Key fingerprint = 29EF 5347 64CB E812 1F6E  A345 93FC 8512 4ECA 7C8F

Deprecated key created on 2004-01-06. Key ID: `0x72D2E007`

Key fingerprint = D3D1 559B EDF0 9317 C29E  80E6 3C81 158E 72D2 E007