$10K MRRin 1 year

3 milestones

Current revenue

$25M ARRas of December 2025Source

Resend ~$25M revenue 2025 (400% YoY from $5M in 2024). $18M Series A from a16z Dec 2024.

Resend: De Código Abierto Primero a $5M ARR con un Equipo de 22 Personas

Founder

Zeno Rocha

Co-Fundadores•Technical•USA

Commitment

Full-time

Experience

Experienced

Product

Resend

Email API para desarrolladores que hace que enviar emails transaccionales y de marketing sea tan simple como Stripe hizo los pagos, con templating de email basado en React.

Type

API / Herramienta para Desarrolladores

Industry

Herramientas para Desarrolladores

Model

Freemium

Marketing Strategy

How Zeno acquired customers

Growth Channel

Twitter / X

Also Used

ComunidadesProduct Hunt

Tech Stack

Tools used to build Resend

React EmailNode.jsTypeScriptNext.jsCustom email infrastructure

The Full Story

TL;DR

Zeno Rocha gastó $25K en un dominio, lanzó una librería de email de código abierto, construyó una lista de espera de 6.338 personas en 7 semanas, luego la convirtió en $5M ARR — la 'Stripe del email'.

Zeno Rocha había estado frustrado con el email en cada empresa en la que trabajó. Como VP de Developer Experience en WorkOS y CPO en Liferay Cloud, vio a los equipos luchar con los mismos problemas de email: plantillas HTML feas, entrega poco confiable, depuración terrible. La infraestructura de email se sentía atrapada en 2005.

El Jab Antes del Derechazo

En diciembre de 2022, antes de anunciar Resend, Zeno lanzó React Email — una librería de código abierto para construir emails con componentes de React. Era gratuita, genuinamente útil, y le dio a los desarrolladores un vistazo de cómo podría verse el tooling de email moderno. Este fue el 'jab' antes del 'derechazo'.

El 4 de enero de 2023, Zeno anunció públicamente que estaba dejando WorkOS para construir Resend. Su tweet de anuncio — de una cuenta con 39K seguidores — obtuvo 999K vistas y 4.634 likes. Posicionó Resend como 'la Stripe del email': API limpia, excelente DX, simplemente funciona.

La Lista de Espera

En lugar de lanzarse inmediatamente, Zeno construyó una lista de espera usando Typeform. En 7 semanas: 6.338 registros. Documentó cada lección públicamente en su blog, incluyendo gastar $25.000 en el dominio resend.com por credibilidad.

YC y Lanzamiento

Resend entró en el batch de invierno 2023 de Y Combinator. Se lanzaron públicamente en junio de 2023, recaudaron $3M en seed de SV Angel (con ángeles incluyendo Dylan Field de Figma, Guillermo Rauch de Vercel, y Paul Copplestone de Supabase), e impactaron 80.000 desarrolladores en 2024. En junio de 2024: $5M ARR con solo 22 personas.

Costo del dominio: $25.000 (resend.com)
Tweet de anuncio: 999K vistas
Lista de espera: 6.338 registros en 7 semanas
Batch de YC: W23
Usuarios: 80.000 desarrolladores (2024)
$5M ARR con 22 personas ($227K ingresos por empleado)

Key Takeaways

Código abierto como go-to-market — lanza una herramienta valiosa gratuita primero, luego construye el producto pagado encima

La marca personal es enormemente importante — 39K seguidores de Twitter se convirtieron en el canal de distribución inicial

El posicionamiento 'la Stripe de X' da claridad instantánea en lo que estás construyendo

Construir en público crea anticipación y confianza — documenta el viaje abiertamente

La credibilidad del dominio importa — $25K en resend.com señaló seriedad a los desarrolladores

Originally published onZeno Rocha (Personal Blog)

Founder proof brief

A one-page proof brief turns Zeno's Resend 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

$10K MRR

Channel

Twitter / X

Output

Action checklist

What a proof brief covers

A one-page brief that turns Zeno's pattern into a testable plan
Channel bet: start from Twitter / X
A risk check before copying the Resend playbook

See what a proof brief covers

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

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Milestone Journey

Zeno achieved 3 milestones on the path to $10K MRR

Primer Cliente

5 months

June 2023

Avg: 3 months

+3 months to next milestone

$1K MRR

8 months

September 2023

27% faster

vs avg 11 months

+10 months to next milestone

$10K MRR

1 year

June 2024

14% faster

vs avg 1 year

1 year

Total journey time

Milestones achieved

Zeno's Path to $10K MRRPremium

The journey, decisions, and context behind this milestone

How Zeno actually did it

6/7 funnel stages sourced

Reconstructed from Zeno'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

Employer problemPivot from Not a direct pivot, but Resend was Zeno's second Y Combinator attempt. An earlier, unrelated consumer app ("LeCheese", a wine-and-cheese recommendation app built on Expo/Firebase) was rejected from YC's Winter 2020 batch in 2019. He applied again in 2022 with Resend, this time in a domain (DevTools/APIs/B2B) closer to his own experience, and was accepted into W23.

Zeno hit the same email problem twice as an employee before starting Resend: as CPO at Liferay Cloud he had high-profile customers complaining about deliverability, and later as VP of Developer Experience at WorkOS he again dealt with emails landing in spam. He and co-founder Bu first shipped React Email (an open-source templating library) as an exploration, then decided the deeper opportunity was the email-sending infrastructure itself, positioning Resend as a developer-first alternative to incumbents founded around 2009-2010.

“I faced the problem of sending emails at scale”

I'm starting my own company (zenorocha.com)

Validation

Built first, validated after

MvpValidated

Built an early prototype under throwaway placeholder domains (zeebbu.com, then klotty.com) before the product had the Resend name, brand, or domain, and put it directly in front of early adopters.

The klotty.com-branded prototype was shared with early adopters to get real usage before any public launch or naming decision.

“it was good enough to start putting it in the hands of early adopters”

Why I spent $25,000 on a domain (zenorocha.com)

WaitlistValidated6338 signups

Ran a public waitlist for about 7 weeks off the back of the founder's existing audience, using a landing page for signups and Typeform afterward to qualify and prioritize who to onboard first.

The waitlist grew to 6,338 signups in 7 weeks (a nearby YC launch-page snapshot two days later showed 6,469), driven mainly by the founder's own social following.

“growing a 6,338 people waitlist in 7 weeks”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

First test users

Existing audience~6338 usersFree testersTwitterLinkedIn

Zeno announced Resend directly to his existing Twitter following (39.4k people, built since 2009) and cross-posted the same announcement to LinkedIn; both drove waitlist sign-ups immediately.

“On January 4th, 2023 at 7:11 am PT, I published the first tweet about Resend”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

Acquisition channels, and whether they worked

Twitter / XLaunchWorked

The launch-day tweet on January 4, 2023 at 7:11am PT was the primary trigger for waitlist growth.

“This tweet had 999.3k views, 4,634 likes, 352 retweets, and 282 replies.”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

Plausibly worked because Zeno had been posting on that Twitter account since 2009, building the 39.4k-follower audience over more than a decade before ever using it to launch a company.

Our analysis, not the founder's claim

Other · LinkedInLaunchWorked

Zeno is not a frequent LinkedIn poster but cross-posted the same Resend announcement there and it performed well.

“it got 107,411 views, 1,378 likes, and 156 comments”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

Other · Build in public (email updates to waitlist)Pre-launchWorked

After the initial announcement, the team kept the waitlist engaged with regular email updates about company news and product progress.

“we started sending them emails about company news and product updates”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

Communities · Y Combinator batch networkLaunchWorked

Resend offered YC-batch companies a direct skip-the-waitlist link, turning the accelerator's own network into an acquisition channel.

“YC companies - you can skip the 6,469 people waitlist using the secret link”

Launch YC: Resend - Email API for developers (Y Combinator launch post, written by Bu Kinoshita and Zeno Rocha)

What didn't work

OpsLaunchCost: time

The team hadn't load- or performance-tested the waitlist landing page on real mobile devices before the high-traffic launch.

“On the day we launched, we got several complaints about performance issues”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

They anticipated mobile sign-ups but did not budget time to test performance on real phones ahead of launch.

“we didn't spend too much time testing the performance on real phones”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

What they did instead: Fixed the performance issues during the launch window itself, but wished it had been done pre-launch.

OpsPre-launchCost: time

The low-friction, single-field waitlist signup form had no email confirmation step, so some sign-ups used fake addresses.

“people could still add fake email addresses”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

The team optimized the form for low friction (a single input field, no confirmation step) and only had light back-end validation.

“we had some back-end validation, people could still add fake email addresses”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

What they did instead: Integrated an email validation service (Emailable) to confirm addresses were real.

OpsPre-launchCost: time

There was no real plan for processing the waitlist once thousands of people had signed up, including a mandatory 1:1 onboarding call for every prospect.

“we didn't have a proper plan to process the waitlist”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

Requiring a manual onboarding call for every single waitlisted prospect could not scale with a 2-person team.

“We initially required every prospect to go through a mandatory onboarding call first (Superhuman style), but we quickly realized that wouldn't scale”

Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com)

What they did instead: Switched to automatically onboarding certain user segments and used a quick Typeform to qualify and prioritize the rest of the backlog.

How it changed as they grew

At launch: 2 people (Two co-founders, Zeno Rocha and Bu Kinoshita, who quit their jobs together and moved to San Francisco after Y Combinator accepted them.)

Accelerator · 2022-11

Seed · $3,000,000 · 2023-07

Series a plus · $18,000,000 · 2024-12

Sources (10 in the founder's own words)

I'm starting my own company (zenorocha.com) · founder-authored · 2023-01
Lessons learned from growing a 6,338 people waitlist in 7 weeks (zenorocha.com) · founder-authored · 2023-02
Resend raises $18M Series A (zenorocha.com) · founder-authored · 2024-12
YC Deal / Our YC story (resend.com, byline Zeno Rocha, Founder & CEO) · founder-authored
Resend (YC W23) raises $18M Series A (Hacker News, founder comments by zenorocha) · founder-authored · 2024-12
Launch YC: Resend - Email API for developers (Y Combinator launch post, written by Bu Kinoshita and Zeno Rocha) · founder-authored · 2023-02
Resend is built by indie hackers (Zeno Rocha, LinkedIn post) · founder-authored · 2024-09
Most people don't know this, but I got rejected from Y Combinator... (Zeno Rocha, LinkedIn post) · founder-authored · 2025-07
Resend raises $3M (resend.com blog, byline Zeno Rocha) · founder-authored · 2023-07
Why I spent $25,000 on a domain (zenorocha.com) · founder-authored · 2023-02

Launch Strategy

How they introduced the product to the world

Waitlist

Initial go-to-market approach

Validation

How they tested demand before building

Waitlist

Method used to confirm market interest

Launch Pricing

Price point when the product first launched

Gratis

Initial pricing strategy

Common for building initial traction

Starting Audience

Whether they had followers before launch

Existing Audience

Leveraged existing followers

Having an audience accelerates early growth

Time Investment

Average weekly hours during building phase

60 hrs

per week on average

Full-time dedication

Initial Investment

Capital required to get started

$25,000

in startup costs

Significant upfront investment

Biggest Challenge

Competir contra proveedores de email establecidos (SendGrid, Mailgun, SES) con un equipo de 2 personas

Unlock Zeno's Full Journey

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Frequently asked questions

How much does Resend make?

Resend reports $25M ARR as of December 2025. Resend ~$25M revenue 2025 (400% YoY from $5M in 2024). $18M Series A from a16z Dec 2024. Source: Zeno Rocha (founder).

What is Resend?

Email API para desarrolladores que hace que enviar emails transaccionales y de marketing sea tan simple como Stripe hizo los pagos, con templating de email basado en React. It operates in Herramientas para Desarrolladores.

How long did it take Resend to reach $10k mrr?

Zeno Rocha took 1 year to reach $10k mrr with Resend.

Was Zeno Rocha a solo founder?

No. Zeno Rocha built Resend with co-founders.

What marketing channel did Resend use to grow?

Resend grew primarily through Twitter / X.

What industry is Resend in?

Resend operates in Herramientas para Desarrolladores.

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