$100K ARRin 1 year

4 milestones

Last known revenue

$4K MRRas of March 2021Source

Last public data 2021. CSS Scan is one-time purchase ($69); CSS Pro is subscription ($30/mo). No 2024-2025 figures disclosed.

Desarrollador brasileño autodidacta de 21 años gana $100K con extensión CSS

Founder

Guilherme Rizzo

Fundador en Solitario•Technical•Brazil (now Taiwan)

Commitment

Full-time

Experience

Experienced

Product

CSS Scan

Extensión de navegador para inspeccionar y copiar CSS.

Type

Extensión de Chrome

Industry

Herramientas para Desarrolladores

Model

Freemium

Marketing Strategy

How Guilherme acquired customers

Growth Channel

Product Hunt

Tech Stack

Tools used to build CSS Scan

JavaScriptChrome Extension APIStripe

The Full Story

Soy de Brasil y construí CSS Scan porque siempre quise saber qué border-radius, box-shadow o font-family tiene un elemento que veo.

Progreso rápido

Me tomó 9 meses llegar a los primeros $10,000 y solo 9 meses más para ganar $60,000 adicionales.

Crecimiento orgánico

No gasté dinero en anuncios pagados, dejé que la efectividad de mi producto hablara por sí sola. 7,000+ personas de 116 países diferentes usan mi extensión.

Primeros $10K: 9 meses
Siguientes $60K: 9 meses
Usuarios: 7,000+ de 116 países

Key Takeaways

Resuelve tu propio problema, construí la herramienta que quería usar

No necesitas anuncios pagados si el producto es genuinamente útil

Product Hunt puede ser una excelente plataforma de lanzamiento inicial

Los desarrolladores autodidactas pueden competir con cualquiera

Originally published onIndie Hackers

Founder proof brief

A one-page proof brief turns Guilherme's CSS Scan playbook into your next test.

See what it covers before you sign up: the pattern worth copying, the channel to test, and the risk to avoid when you adapt this story.

Pattern

$100K ARR

Channel

Product Hunt

Output

Action checklist

What a proof brief covers

A one-page brief that turns Guilherme's pattern into a testable plan
Channel bet: start from Product Hunt
A risk check before copying the CSS Scan playbook

See what a proof brief covers

See what it covers first. Create an account only if you choose to unlock.

Inspired by Guilherme's journey? Generate a business idea in the Herramientas para Desarrolladores space using AI and real founder data.

Milestone Journey

Guilherme achieved 4 milestones on the path to $100K ARR

Primer Cliente

7 days

August 2018

93% faster

vs avg 3 months

+3 months to next milestone

$1K MRR

$1,000

3 months

June 2019

73% faster

vs avg 11 months

+6 months to next milestone

$10K MRR

$10,000

9 months

May 2019

57% faster

vs avg 1 year

+9 months to next milestone

$100K ARR

$100,000

1 year

September 2020

50% faster

vs avg 3 years

1 year

Total journey time

Milestones achieved

Guilherme's Path to $100K ARRPremium

The journey, decisions, and context behind this milestone

How Guilherme actually did it

7/7 funnel stages sourced

Reconstructed from Guilherme's own published sources. Quoted claims are the founder's words, verified verbatim; anything marked as our analysis is exactly that.

Where the idea came from

Personal pain

Guilherme built CSS Scan to answer a question he kept asking himself as a developer: what border-radius, box-shadow, or font-family does this element have. He was directly inspired by an existing tool, WhatFont.

“I built CSS Scan because I always wanted to know what border-radius, box-shadow, or font-family an element I see has.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Validation

Validated before building

Talking to usersValidated

Before writing any code, he posted in Brazilian developer Facebook groups asking whether people would pay $1 for the extension idea. He judged the response good enough to proceed. In hindsight he called this validation weak and said he would now use pre-sales instead.

Reached out to Brazilian developer Facebook groups to ask if people would pay $1 for the idea before building it.

“I reached out to some Brazilian Developers Facebook groups, asking if they would pay $1 for this extension, and the result was good enough, so I started coding.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

First test users

Online communityPaying from day oneProduct Hunt

First users came in through the Product Hunt launch itself; there was no separate free-trial user pool before the paid version went live.

“After the 50 hours of work, which took like a month, I launched it on Product Hunt and it was a success (compared to my previous launches).”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

First paying customer

Online communityPaywall from launch$1.99

Pricing was Pay-What-You-Want with a $1.99 floor from day one, so the first paying customers converted directly off the Product Hunt launch traffic rather than upgrading from a free tier.

“In the beginning, the pricing model was Pay What You Want (but with a minimum of $1.99).”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Acquisition channels, and whether they worked

Product Hunt · First Product Hunt launchLaunchPartially worked

The first launch was a bare-minimum post, timed for a Tuesday to catch more traffic.

“The first launch was pretty much just posting it, that's it. But I posted it on a Tuesday (to get more traffic).”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

It generated traction but little revenue because the price was set far too low and the landing page did not convert well.

“the price was sooo low ($1.99) that I didn't make that much money.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Product Hunt · Second Product Hunt launchLaunchWorked

For the second launch he pre-warmed the audience with Twitter reminders a week and a day beforehand, after also improving the product and landing page.

“For the second launch, I also posted some reminders on Twitter like 7 days and 1 day before the launch, reminding them what day I'd launch and etc.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

The combination of a better product, a better landing page, and pre-launch hype made the second Product Hunt launch far more effective.

“the second launch was 20x better in revenue.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Communities · Lifetime Deals Facebook groupsScalingWorked

Lifetime Deals Facebook groups were named among the channels that drove the most traffic and sales.

“The best channels so far were Product Hunt (2 launches), Life-time Deals Facebook Groups, Youtube videos (such as this one from WpTuts), Twitter, word of mouth, and SEO.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Communities · Indie HackersScalingWorked

Indie Hackers was one of the recurring promotion channels he named as working well for him.

“I promote it on Product Hunt, Indie Hackers, Hacker News, Reaching Press, Twitter, Reaching Blogs, Answering Quora questions, Making Discounts, Sharing discount links, etc.”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

He described this same list of channels as the ones that perform best for him.

“That's what works better for me yet.”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

Other · Hacker NewsScalingWorked

Hacker News was named as a recurring promotion channel that works for him.

“I promote it on Product Hunt, Indie Hackers, Hacker News, Reaching Press, Twitter, Reaching Blogs, Answering Quora questions, Making Discounts, Sharing discount links, etc.”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

Other · Press outreachScalingWorked

Reaching out to press was one of the channels he named as part of his regular promotion mix.

“I promote it on Product Hunt, Indie Hackers, Hacker News, Reaching Press, Twitter, Reaching Blogs, Answering Quora questions, Making Discounts, Sharing discount links, etc.”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

Other · Blog outreach and Quora answersScalingWorked

He also reached out to blogs and answered Quora questions as part of ongoing promotion.

“reach influential people to help you share the product”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

Other · YouTube video (WpTuts)ScalingWorked

A YouTube video made by WpTuts about CSS Scan was named as one of his best-performing channels.

“Youtube videos (such as this one from WpTuts)”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Twitter / XScalingWorked

He posted on Twitter daily as part of his organic growth routine, alongside using it for pre-launch reminders.

“post on twitter every day (balance business with fun things about life)”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

Word of MouthScalingWorked~99% of growth

He described growth as almost entirely organic rather than paid, twice, in response to direct questions about go-to-market strategy.

“It is organic, mostly (around 99.9%)”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

SEO / ContentScalingWorked

SEO was named among his best-performing channels for traffic and sales.

“The best channels so far were Product Hunt (2 launches), Life-time Deals Facebook Groups, Youtube videos (such as this one from WpTuts), Twitter, word of mouth, and SEO.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

What didn't work

Product scopePre-launch

While still in school, he attempted two "Silicon Valley-ish" startups, one in education and one in fashion; both failed.

“I've been trying to build Silicon Valley-ish startups when I was in school (tried Education, Fashion, both failed)”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Product scopePre-launchCost: time

Built mprove as the first entry in a self-imposed "3 Products in 3 Months" challenge; it earned $129 in revenue.

“mprove ($129 in revenue)”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

What they did instead: CSS Scan, the third product of the challenge, which scratched a problem he personally had

Product scopePre-launchCost: time

Built Moniesto as the second entry in the same challenge; it earned roughly $60 in revenue, less than the simpler mprove.

“Moniesto (maybe $60 in revenue haha)”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

What they did instead: CSS Scan, the third product of the challenge, which scratched a problem he personally had

How it changed as they grew

Today: 1 person (solo founder)

Bootstrapped

Pricing restructure: Pay-What-You-Want, $1.99 minimum → Fixed $10

Seeing customers voluntarily pay $5, $10, and $25 under the PWYW model, he gradually raised the price until it settled at a fixed $10.

“After seeing some people paying $5, $10, $25, I slowly raised the price. Until one day it was already $10, so I made it fixed pricing.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Pricing new tier: Single $10 license → License packages of 2, 5, and 10

His wife suggested adding license packages, after which they kept raising prices further.

“my wife suggested that I add packages of licenses (2 licenses, 5 licenses, 10 licenses) and we kept raising the price.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Pricing increase: License packages → $80 lifetime license

Continued price testing eventually settled on an $80 lifetime license as the current price at the time of the AMA.

“we kept raising the price. Now the extension costs $80 for a lifetime license.”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Pricing new tier: One-time lifetime license (CSS Scan Basic) → CSS Scan Pro subscription ($20/month, $120/year)

He launched a subscription-priced sibling product, CSS Scan Pro, alongside the original one-time-purchase extension.

“Now I'm also trying a subscription model on browser extensions with the newest CSS Scan premium product: https://cssscanpro.com”

Indie Hackers: "$70,000 in revenue with CSS Scan browser extension"

What broke as they grew

The core constraint on charging for a browser extension is that most users expect extensions to be free, so monetizing one takes deliberate, sustained pricing work.

“It's not easy tho because everyone expects extensions to be free”

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!"

Sources (3 in the founder's own words)

Indie Hackers AMA: "I made over $100,000 with a browser extension (CSS Scan), AMA!" · founder-authored · 2021-03
Indie Hackers: "$70,000 in revenue with CSS Scan browser extension" · founder-authored · 2020-01
Indie Hackers Show IH: "CSS Scan - Instantly check or copy computed CSS of any element on the internet" · founder-authored · 2019-05

Persistence

Projects attempted before finding success

failed projects before this one worked

Learned from a previous attempt

Launch Strategy

How they introduced the product to the world

Product Hunt

Initial go-to-market approach

High-visibility single-day launch

Validation

How they tested demand before building

Hablar con Usuarios

Method used to confirm market interest

Launch Pricing

Price point when the product first launched

Menos de $20/mo

Initial pricing strategy

Starting Audience

Whether they had followers before launch

Started from Zero

Built audience alongside the product

63% of founders in our database started from zero

Time Investment

Average weekly hours during building phase

50 hrs

per week on average

Full-time dedication

Initial Investment

Capital required to get started

$500

in startup costs

Minimal investment — software and domains

Biggest Challenge

Todos esperan que las extensiones sean gratuitas

Unlock Guilherme's Full Journey

See the complete breakdown: launch strategy, validation methods, startup costs, expert analysis, replication playbook, and more actionable insights.

Upgrade to Premium

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Frequently asked questions

How much does CSS Scan make?

The last known public figure for CSS Scan is $4K MRR as of March 2021. Last public data 2021. CSS Scan is one-time purchase ($69); CSS Pro is subscription ($30/mo). No 2024-2025 figures disclosed. Source: Indie Hackers.

What is CSS Scan?

Extensión de navegador para inspeccionar y copiar CSS. It operates in Herramientas para Desarrolladores.

How long did it take CSS Scan to reach $100k arr?

Guilherme Rizzo took 1 year to reach $100k arr with CSS Scan.

Was Guilherme Rizzo a solo founder?

Yes. Guilherme Rizzo built CSS Scan as a solo founder.

What marketing channel did CSS Scan use to grow?

CSS Scan grew primarily through Product Hunt.

What industry is CSS Scan in?

CSS Scan operates in Herramientas para Desarrolladores.

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The Full Story

Soy de Brasil y construí CSS Scan porque siempre quise saber qué border-radius, box-shadow o font-family tiene un elemento que veo.

Progreso rápido

Me tomó 9 meses llegar a los primeros $10,000 y solo 9 meses más para ganar $60,000 adicionales.

Crecimiento orgánico

No gasté dinero en anuncios pagados, dejé que la efectividad de mi producto hablara por sí sola. 7,000+ personas de 116 países diferentes usan mi extensión.

Primeros $10K: 9 meses
Siguientes $60K: 9 meses
Usuarios: 7,000+ de 116 países

Key Takeaways

Resuelve tu propio problema, construí la herramienta que quería usar

No necesitas anuncios pagados si el producto es genuinamente útil

Product Hunt puede ser una excelente plataforma de lanzamiento inicial

Los desarrolladores autodidactas pueden competir con cualquiera

Originally published onIndie Hackers

Desarrollador brasileño autodidacta de 21 años gana $100K con extensión CSS

The Full Story

Progreso rápido

Crecimiento orgánico

Key Takeaways

A one-page proof brief turns Guilherme's CSS Scan playbook into your next test.

What a proof brief covers

Milestone Journey

Primer Cliente

$1K MRR

$10K MRR

$100K ARR

Unlock Guilherme's Full Journey

Frequently asked questions

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Join founders learning from real success stories

Browse Stories

Desarrollador brasileño autodidacta de 21 años gana $100K con extensión CSS

The Full Story

Progreso rápido

Crecimiento orgánico

Key Takeaways

A one-page proof brief turns Guilherme's CSS Scan playbook into your next test.

What a proof brief covers

Milestone Journey

Primer Cliente

$1K MRR

$10K MRR

$100K ARR

Unlock Guilherme's Full Journey

Frequently asked questions

More Stories You Might Like

From Paris waiter to $250K in 5 months selling a code boilerplate

How I made $100K in 2 weeks with an AI headshot tool

How I built a landing page builder to $10K MRR as a solo founder

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Enjoyed this story?

Join founders learning from real success stories