LLenny's Podcast
← All episodes
Sebastian Barrios08 June 2025

How Mercado Libre built Latin America's most valuable company: 18k engineers, 30k deploys a day, and their own fleet of planes

6Frameworks
15Insights

Frameworks in this episode

Leadership4 steps

Cascade the Vision, Delegate the Work

Run a huge org on high-level objectives and tight feedback loops instead of cascading OKRs

Read →
Leadership4 steps

Culture Is What You Do

Make failure genuinely safe by rewarding bold-but-wrong bets in public, not by writing it on the wall

Read →
Leadership3 steps

Engineer-Owned Product

Collapse the product/engineering divide by giving ownership to whoever is closest to the problem

Read →
Mindset3 steps

Fundamentals-First Hype Filter

Engage the technology, run the real-world numbers, then reject the totalizing claim, not the tech

Read →
Strategy2 steps

Observe Users, Don't Just Ask Them

Watch what users actually do, because watching your assumptions get crushed beats any interview

Read →
Productivity3 steps

The Weekly State-of-Me Email

Write a self-initiated weekly note of what worked, what didn't, and what's blocked

Read →

Insights & moments

The myth-busts, hot takes, explainers, and tools worth keeping.

Hot Take· 2

Hot Take23:00

Observe users more than you talk to them

Against the common advice to talk to and listen to users, Sebastian argues that observing them works best. Watching people actually use the product crushes assumptions in real time — his example is a form field labeled 'email, name' where users dutifully type both their email and name into the single field because that's what was asked of them.

  • Common advice is to talk to and listen to users — it only works sometimes
  • What works best is observing users, including in research sessions
  • Watching real usage crushes your assumptions before your eyes
  • Example: a field labeled 'email, name' makes users type both into one box

“we like to observe users more than talk to users.”

Sebastian Barrios · 23:00

“we've seen that what works best is just to observe them.”

Sebastian Barrios · 23:00
#user-research#product#ux
Hot Take41:00

How he avoids hype cycles: know the fundamentals and run the numbers

Sebastian describes staying pragmatic about hyped technologies without ignoring them — he mined his first Bitcoin around 2010-2012 and uses deep research heavily. He loves crypto's technology and distributed consensus, and Mercado Libre even has its own cryptocurrency useful where US dollar access is hard. But when the claim becomes 'every single thing on the planet will run on the blockchain,' his alarms go off — a technology can be great and successful without taking over the world, and the same logic applies to AI.

  • Mined or bought his first Bitcoin around 2010-2012; learned lessons on selling
  • Skeptical of most things; relies heavily on deep research
  • Loves crypto's distributed consensus but ran the numbers on throughput limits
  • Mercado Libre has its own crypto, useful where US dollar access is limited
  • A technology can be great and successful without having to take over the world

“I'm definitely skeptic of most things.”

Sebastian Barrios · 42:00

“That's where some of my alarms start to go off”

Sebastian Barrios · 43:30
#crypto#ai#hype#decision-making

Explainer· 4

Explainer06:00

The scale of Mercado Libre: $100B, 18k engineers, 5M packages a day

Sebastian explains that Mercado Libre is a vertically integrated e-commerce marketplace with its own planes, trucks, and distribution network, plus a fintech operation roughly equal in size offering accounts, credit cards, and loans. It's the most valuable company in Latin America at over $100 billion, with around 100 million users and one of the largest engineering teams on the planet. The delivery operation alone ships over 5 million items per day across Latin America.

  • Vertically integrated: owns its own airplanes, trucks, and distribution network
  • The e-commerce and fintech sides of the business are almost the same size
  • Valued at over $100 billion — one of the top-valued companies on the planet
  • Around 100 million users, customers, and sellers on the platform
  • Delivers over 5 million packages/items per day across Latin America

“We deliver over 5 million packages per day or items.”

Sebastian Barrios · 07:00
#mercado-libre#scale#ecommerce#fintech
Explainer08:30

Why Mercado Libre doesn't separate engineering from product

Sebastian describes a core operating philosophy: they don't draw a hard line between where engineering stops and product begins. Ownership of a product isn't assigned by job title but by who is best for the role, which in most cases turns out to be the technical leaders. The idea is to hold the whole context — technology, business needs, and user needs — in a single mind.

  • Product ownership is decided by who's best for the role, not by title
  • In the majority of cases the owner is an engineering leader or tech lead
  • The goal is to keep technology, business, and user context in one person
  • One mind holding the full context can deliver a clearer vision to the team

“it's hard to separate where sort of like engineering stops and product begins.”

Sebastian Barrios · 09:00

“We we we're not going to determine who's going to own the product just based on the title.”

Sebastian Barrios · 09:00
#product#engineering#org-design#ownership
Explainer10:00

Fewer than 5% carry the PM title — and hiring has a strong engineering bias

With around 18,000 developers, fewer than 1,000 people hold the PM title — under 5%, versus 10-30%+ at other companies. Hiring tests mainly for engineering skills with a strong bias toward being technical and deep in the details. There is little tolerance for a candidate who can't discuss the technology being used; product inclination is discovered later, once inside the company.

  • Fewer than 1,000 people hold the PM title out of ~18,000 developers (under 5%)
  • Other companies often run 10-30%+ PMs
  • Interviews test mainly for engineering skills, with some product testing
  • No tolerance for 'I need to check with someone about the technical details'
  • Product inclination is identified after joining, not gated at hiring

“So I think it's less than 1,000.”

Sebastian Barrios · 10:00

“we have a strong bias for uh engineering for for for being technical”

Sebastian Barrios · 11:00
#hiring#product#engineering#org-design
Explainer16:30

Building features with no new code by wiring up existing microservices

Sebastian describes an internal AI platform called Verie that abstracts away complexity around data access and authorization. Building on their platform approach, they can extract the functionality of every microservice and have agents combine parts of different services to build new end-to-end features with a UI — without writing new code. He frames a future where UIs and apps could be entirely generated and personalized per user.

  • Internal AI platform 'Verie' abstracts data access and authorization
  • They extract functionality from every microservice for agents to use
  • Agents combine existing services into new end-to-end features with a UI
  • No new code is written — existing platform functionality is recombined
  • Envisions fully generated, personalized UIs predicting a user's next action

“We developed an internal platform called Verie”

Sebastian Barrios · 16:30

“we we're seeing great results with skipping code entirely.”

Sebastian Barrios · 17:00
#ai#agents#platform#microservices

Story· 4

Story25:30

30,000 deployments a day — more than one per developer

Sebastian shares that Mercado Libre makes around 30,000 changes to production per day — PRs, deploys, configuration changes, database updates. There's no way for anyone to review what all 30,000 changes are doing; some are automated. He frames the resulting high speed of execution as part of operating in some of the most competitive markets on the planet, like Brazilian e-commerce.

  • Around 30,000 deployments/changes to production per day
  • Includes PRs, config changes, and database updates; some are automated
  • That's more than one change per developer per day
  • No one can manually check what all 30,000 changes are doing
  • Brazil is called one of the most competitive e-commerce markets on the planet

“we do around 30,000 deployments per day of like changes to production.”

Sebastian Barrios · 25:30

“That's that's more than one per developer.”

Lenny Rachitsky · 26:00
#engineering#deployment#scale#velocity
Story44:30

Steve Jobs personally called to pull his battery-draining app

As a teenager Sebastian built an app that intentionally drained your phone's battery — partly to learn the phone's sensors, partly for the old advice of fully discharging a battery before recharging. In the early App Store days, Apple's executives (including Steve Jobs) were personally calling developers whose apps were rejected, to avoid PR blowups. Steve called Sebastian; when he pushed back that no rule banned draining the battery, Steve said Apple had just added one — a rule created specifically because of his app.

  • The app deliberately drained your battery by turning on all sensors at once
  • Rationale: learning the phone's sensors, plus the old full-discharge battery advice
  • Apple execs, including Steve, personally called developers to avoid press stories
  • Sebastian pushed back that no App Store rule banned draining the battery
  • Apple added a new rule against overly draining the battery, made for his app

“it was an an an app that literally helped you drain your phone's battery.”

Sebastian Barrios · 44:30

“he told me check again because we just added a new rule”

Sebastian Barrios · 47:00
#steve-jobs#app-store#story#early-career
Story49:30

The five-minute-call app that hit #1 in 19 countries — and won him his wife

To dodge phone charges on a '5 numbers for 5 minutes free' plan (which billed the full five minutes if you went one second over), Sebastian built a simple app that notified you when you neared five minutes so you could hang up and call again. He built it to keep talking to his girlfriend — whom he ended up marrying. It cost $100 to upload, he figured he needed to sell ~100 copies, and it exploded into the top-selling app in Mexico and many countries, launching a mobile app development business.

  • Phone plans billed the full 5 minutes if you went one second over on a free call
  • The app alerted you near the 5-minute mark so you could hang up and redial
  • He built it to keep talking to his girlfriend — now his wife
  • $100 to upload; his 'business plan' was selling ~100 copies at $1
  • Became the top-selling app in Mexico and many countries; no backend or ad cost
  • Multinationals and governments then asked him to build apps for them

“it turned out to be a good investment because I ended up marrying my uh girlfriend.”

Sebastian Barrios · 50:30

“it became the top selling app in Mexico and in a lot of other different countries.”

Sebastian Barrios · 51:00
#story#app-store#entrepreneurship#early-career
Story1:04:30

Raised like a spy: survival camps and being dropped in Mexico City

Sebastian credits his intensely independent upbringing for his sense of agency. His mother said she wanted to train her kids like spies: waking them one morning to leave immediately for a no-gear survival camp where they found their own water and built their own shelter, and dropping them in the middle of Mexico City to find their own way home using public transit or by asking for help. He reframes what she called 'independence' as agency — solve your problems, go get things done.

  • His mother said she wanted to train the kids like spies
  • A surprise 'camping' trip was actually a no-gear survival camp
  • They had to find their own water, build shelter, boil water, and start fires
  • She'd drop them in the middle of Mexico City to find their own way home
  • She called it independence; he reframes it as agency

“she wanted to train us like spies.”

Sebastian Barrios · 1:04:30

“she would drop us in the like in the middle of the city”

Sebastian Barrios · 1:06:00
#upbringing#agency#story#independence

Tool· 1

Tool38:30

The weekly 'what I got done' email he's written for years

Sebastian writes himself a weekly email covering what he did, what worked, what didn't, and interesting things he discovered, then shares it with the executive team and his CEO. He clarifies he doesn't expect others to send it to him — it's a personal practice that helps him track progress and surface blockers. Lenny notes he wrote about the same idea, calling it the 'state of me' email, and they realize Sebastian likely got it from Lenny's post.

  • A simple weekly email: what happened, what worked, what didn't, what's stuck
  • It's a personal practice, not a demand that reports send one to him
  • He shares it with the executive team and the CEO he reports to
  • It frees up weekly 1:1 time from status updates for higher-value discussion
  • Lenny's version is the 'state of me' email: got done, next priorities, blockers

“you can write like a weekly email to your boss or to your team”

Sebastian Barrios · 39:30
#management#communication#productivity#tools

Takeaway· 4

Takeaway12:30

At Mercado Libre, the first C-level question is the user experience, not revenue

Sebastian contrasts Mercado Libre's leadership culture with the stereotype of other companies. When a feature is presented at the C-level, the first questions are about copy, pixels, and how the user will experience it — not how much revenue it will generate. The bet is that putting users before revenue turns into revenue over the long term.

  • Leadership is deeply technical and detail-oriented, down to copy and pixel placement
  • The company has operated in 'founder mode' for a long time
  • Other companies often ask 'how much revenue' or 'what metric moves' first
  • Mercado Libre's CEO asks 'how's the user going to experience this?' first
  • Putting users before revenue is expected to convert to revenue long-term

“For Marcos, our SEO, the first question is always, okay, how's the user going to experience this?”

Sebastian Barrios · 13:30
#leadership#product#culture#founder-mode
Takeaway19:30

No OKRs, tolerated failure, and 'freedom and responsibility' at scale

Sebastian names the key ways of working that let 18,000 developers ship: teams are empowered to take risks on what to build and won't be fired for a bet that didn't land (though quality failures and outages are far less tolerated). They don't run OKRs cascading down — instead they set high-level, not-very-long-term objectives and let teams decide the rest. Leadership stays hands-on and goes deep on the most important projects.

  • Teams are empowered to make mistakes on what to build
  • Bad quality, outages, and 'the product wasn't good' failures are much less tolerated
  • No OKRs cascading down — objectives stay high-level and short-ish term
  • A 10-year plan doesn't fit a fast-changing, heavily regulated multi-country market
  • Leadership can't check everything but goes deep on the most important projects

“we don't operate with OKRs”

Sebastian Barrios · 20:00

“do whatever literally whatever you think is best for uh our users”

Sebastian Barrios · 21:00
#culture#management#okrs#autonomy
Takeaway28:00

The talent flywheel of being the top company in your region

Sebastian argues you can build amazing technology outside the Bay Area because great talent exists everywhere by statistical distribution. The one thing you don't get outside big tech hubs is a high concentration of other top companies — so if you become the best in your region, you set your own path and build things that haven't been built before. To get the flywheel running where the best come to you, you have to be the best in that market, eventually.

  • Great talent exists everywhere by statistical distribution
  • The one disadvantage outside tech hubs is you're the only top company
  • Being the top company means setting your own map and destination
  • The flywheel is hard to start — you can't be the best when just getting started
  • You have to be the best 'eventually' to get the flywheel running

“by statistical definition there's great talent everywhere”

Sebastian Barrios · 28:30

“Yeah, maybe you could say you have to be the best eventually.”

Sebastian Barrios · 29:30
#talent#hiring#geography#strategy
Takeaway31:00

Culture is what you do, not what you write on the walls

On actually making failure safe, Sebastian says culture isn't what you write on the walls or your website — it's what you do. The signals that matter are who gets promoted, who gets public praise, what happens after something fails, and how leadership talks about it. If someone who took a bold, well-reasoned risk gets fired when it doesn't work, you're not living your stated values; if they get praised or even promoted, that message is extremely powerful.

  • Culture is defined by actions, not slogans on walls or websites
  • Load-bearing signals: promotions, public praise, and how failures are discussed
  • System outages are unacceptable; bold-vision bets that fail are not penalized
  • Firing the person who led a well-reasoned failed bet contradicts your stated values
  • It must start with top management and be propagated by leaders into teams

“it's not what you write on the walls or what you put on on on your website.”

Sebastian Barrios · 31:00

“You need to live it. You need to show it.”

Sebastian Barrios · 32:30
#culture#leadership#failure#risk