Castle YC Application

Winter 2016Active

Castle went through Y Combinator in the Winter 2016 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: Winter 2016
Industry: B2BSecurity
Team size: 20
Status: Active
Launched: 2015

Founders

Sebastian Wallin
Johan Brissmyr

What Castle does

Instantly stop automated and human-originated account takeovers, fake accounts, and any behavior that violates your platform policies.

Castle's YC application, reconstructed

Y Combinator application

Castle, Winter 2016 batch. The real form questions, answered from public data.

Founders2
Company7
Progress7
Idea4
Equity3
Curious2
Batch Preference1

Company

Company name

Castle

Describe what your company does in 50 characters or less.

Block bots & bad behavior

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

We built a security platform that detects and stops bots, fake accounts, and account takeovers in real time. Our product analyzes behavioral signals to instantly block automated and malicious human activity that violates platform policies.

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

We live in San Francisco, CA, and have a remote team. The company would continue to be based in San Francisco after YC.

Explain your decision regarding location.

San Francisco has a strong security and SaaS community with access to customers and talent. Being remote helps us hire the best engineers regardless of location while keeping our base where the startup ecosystem is dense.

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 Castle YC application?

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