Bun YC Application

Summer 2019Acquired

Bun went through Y Combinator in the Summer 2019 batch as a B2B company. Below: what the company does, who founded it, and its application to YC, reconstructed question by question in the real YC form.

YC batch: Summer 2019
Industry: B2BInfrastructure
Team size: 13
Status: Acquired
Launched: 2025

Founders

Jarred SumnerFounder

What Bun does

Bun is an incredibly fast all-in-one toolkit for building, installing, running, and testing JavaScript and TypeScript. We were born out of frustration with the fragmented, slow JavaScript ecosystem and are on a mission to make JavaScript development faster and more productive.

Bun's YC application, reconstructed

Y Combinator application

Bun, Summer 2019 batch. The real form questions, answered from public data.

Founders2
Company7
Progress7
Idea4
Equity3
Curious2
Batch Preference1

Company

Company name

Bun

Describe what your company does in 50 characters or less.

An incredibly fast all-in-one JavaScript toolkit

What is your company going to make? Please describe your product and what it does or will do.

We are building Bun, a toolkit that bundles together building, installing, running, and testing for JavaScript and TypeScript. The goal is to replace the fragmented and slow existing ecosystem with a faster, more integrated tool developers actually want to use.

Where do you live now, and where would the company be based after YC?

We live in San Francisco, and after YC the company will be based here as well.

Explain your decision regarding location.

San Francisco is where the core team lives and where much of the JavaScript infrastructure community is. Staying here keeps us close to users and potential partners.

21 more answers in the full application

Founders, Progress, Idea, Equity, Curious, Batch Preference are in the full version. Create a free account to open it in YC Insights, next to every other YC batch.

See full application

Frequently Asked Questions

Is this the real Bun YC application?

No. Y Combinator keeps submitted applications private. This is a reconstruction: the real YC form questions, answered from Bun's public data (launch notes, founder backgrounds, product description). It shows how a company like Bun would present itself to YC, not the text they submitted.