Obie Fernandez

CTO @zardotapp ✤ Partner at ­✤ Bestselling Author ✤ DJ/Producer (aka Kyberian, KNBI)

[Obie Fernandez @obie]

Honored to have not one but two (!) tracks featured on the latest @ILikeItPure compilation album, including "Foreplay" another previously unreleased collaboration with @richsolarstone himself. Also kind of cool to hear "Naked" mixed in between Eelke Kleijn and Tiesto, a couple of my musical heroes!

Wanted to express my sincerest gratitude to Rich and Paula for their consistent support, mentorship, and above all such a genuine friendship. 🥰

[Obie Fernandez @obie]

My keynote speech from @RubyConfAT 2026, recorded live on May 30, 2026 at Das MuTh theatre in Vienna.

“Obie Fernandez — author of The Rails Way and Patterns of Application Development Using AI, CTO at ZAR — tells the story of two chefs in two very different kitchens, building a fintech together with AI.

One chef is Sebastian, ZAR's lead architect: a perfectionist running a Michelin-star kitchen, where almost every line of ZAR Core — a stablecoin wallet serving underbanked populations across a 60+ country roadmap — touches users' money. The other is Obie: idealist, delegator, running three or four Claude Code sessions at once on internal tools, never reading every line, wearing the --dangerously-skip-permissions t-shirt on stage. "I'm a control freak and you're a free spirit." What they share: a total intolerance for technical debt. What differs is when they pay — Sebastian up front, with planning and specifications; Obie afterwards, with cleanup passes he finally has the bandwidth to make.

Highlights:
• The cautionary tale: kr8d, a vibe-coded fun-employment app that collapsed under its own featureweight
• Sebastian's kitchen by the numbers: a single 37,000-line cleanup PR, deleting five lines for every line added — while features keep shipping
• Obie's kitchen: five Rails apps, 1000+ commits, 400k+ lines in five months — Nexus, Agentis, Imperium, and Eventis, an event bus that's an active participant in the conversation
• The /goal workflow: plan, implement, ship, deploy, verify — then walk to the cafe and supervise from your phone
• Compounding: every problem you solve should make the next one cheaper — 75 custom skills, /fresh, /ship, and a skill that writes skills
• The two-week Flutter → React Native rewrite the team said would take two months
• Why Rails conventions matter more than ever: every shape choice you leave open is an invitation for the model to get non-deterministic
• Open source from ZAR: Servus (a disciplined, schema-validated service-object pattern), Amounts (fungible amounts with units and type safety), and Praxis (conceptual linting — RuboCop at the level of intent, not syntax)
• The uncomfortable truth about code review in the agent era — and why automated constraints will save us from ourselves

"Don't tolerate debt. It's not needed anymore."

https://t.co/yKanpSTkwK

[Obie Fernandez @obie]

Gusto’s loss is our gain!! Thrilled to welcome codenamev to my dream team at ZAR

[Valentino Stoll @thecodenamev]

It is bittersweet, but today is my last day at @GustoHQ. I have met and worked alongside so many talented people, and I am so grateful for the opportunity.

Next week, I am so pumped to be joining the stellar team at @zardotapp, back to my #Ruby roots, and helping a billion people living in countries with unstable money!

[Obie Fernandez @obie]

Today at @rubyconf I mentioned a slew of open source projects that we’ve published at @zardotapp

Here’s the link https://t.co/DOP1UWES7n

[Obie Fernandez @obie]

Legends of @rubyconf !!!

@chadfowler @pragdave @yukihiro_matz @rich_kilmer @hal_fulton were at the first @rubyconf in 2001

[Obie Fernandez @obie]

Hung out with @samruby today (one of my all time tech heroes!) He presented the most mindblowing stuff I’ve seen recently at @rubyconf 2026

[Obie Fernandez @obie]

@TO Can’t go heh 😏

[Obie Fernandez @obie]

@thedatadavis @squarespace Exactly that. Paying so many years for a service that had free alternatives.

[Obie Fernandez @obie]

Goodbye @squarespace ... kind of nauseating that I paid you over a hundred dollars a year since 2012 to host my personal website https://t.co/Ysn0Kkf1lr

Today Fable and friends ported me over to free hosting on Github and Cloudflare for less than $40. Side bonus: I'll probably keep my website more up to date now too, just gotta ask Claude to help me with that.

[Obie Fernandez @obie]

@squarespace

[Obie Fernandez @obie]

Thinking of buying some PCs to do local inference for my agent fleet. How are people out there getting that done these days? Judging by the shipping date estimates on apple hardware I'm guessing there's better options than a stack of Mac Minis.

[Sahil Bloom @SahilBloom]

Optimism is the ultimate life hack.

[Obie Fernandez @obie]

Listen now https://t.co/vq5tDjlRKF

[Obie Fernandez @obie]

Honored to have not one but two (!) tracks featured on the latest @ILikeItPure compilation album, including "Foreplay" another previously unreleased collaboration with @richsolarstone himself. Also kind of cool to hear "Naked" mixed in between Eelke Kleijn and Tiesto, a couple of my musical heroes!

Wanted to express my sincerest gratitude to Rich and Paula for their consistent support, mentorship, and above all such a genuine friendship. 🥰

[Aaron Francis @aarondfrancis]

No shade to Sahil specifically, but this is illustrative of a broader point: take every hot take you see on x dot com the everything app with a *huge* grain of salt.

Completely ignoring hot takes is also acceptable.

[Obie Fernandez @obie]

Would I sustain a few hours of hard techno just to witness this light show in person? Yes, I believe I would.

[Trino DJ @trinodj]

German hard techno DJ and producer Klangkuenstler brought his Outworld production to Lyon, and the production truly looks out of this world. He transformed the venue with his signature Mega Reaktor tunnel as 14,000 fans attended the debut French edition of the show.

[Obie Fernandez @obie]

@bcherny @yheushen Can you respect —dangerously-skip-permissions even in agent mode please? 🙏🏻 I keep finding myself in auto mode even if I didn’t ask for it

[Obie Fernandez @obie]

Belt and suspenders, wedged, hardening...

What other programming terms feel like they weren't quite as popular until claude code started mentioning them all the time?

[Obie Fernandez @obie]

@jun_song it's a better cheaper haiku for lots of stuff

[Obie Fernandez @obie]

@DamirWallener I don't consider myself a manager per se, but I'm good at delegating which is maybe the core skill that you're ascribing to managers? perhaps I'm just an outlier in that most of my managerial experience, if you can call it that, is as an executive

[Obie Fernandez @obie]

I'd argue that you don't really understand our agentic future until you've witnessed a half dozen autonomous AI team members hashing out a problem amongst themselves in a Slack thread.

They generate a large volume of complex verbiage that is more than I can reasonably expect any human (including myself) to try to fully comprehend. But instead of seeing that as a problem, you just skim and trust that the AI what they're doing.

I say this as someone who is a very, very fast reader with extremely high comprehension. Slow readers are in for a world of hurt, if not already there.