# Vasek Mlejnsky

> Vasek Mlejnsky is the co-founder and CEO of E2B, an open-source cloud runtime that gives AI agents secure, isolated sandboxes to run code and use real tools. Raised in a small Czech town, he moved to San Francisco in 2021 through the Pioneer accelerator with his sixth-grade friend and co-founder Tomas Valenta. After pivoting through several developer-tool ideas, the pair launched E2B in 2023. By 2025 the platform was used by 88% of Fortune 100 companies and had run hundreds of millions of sandbox sessions, and E2B closed a $21M Series A led by Insight Partners.

- **Role:** Co-Founder & CEO at E2B
- **Organizations:** E2B
- **From:** Czech Republic
- **Nationality:** Czech
- **Education:** Computer Science, Charles University
- **Known for:** Co-founded and leads E2B, adopted by 88% of Fortune 100 companies, Raised $21M Series A led by Insight Partners (2025), bringing total funding to roughly $32M, Built infrastructure that has run hundreds of millions of AI agent sandbox sessions

## Career timeline

- **2021** — Moved from the Czech Republic to San Francisco through the Pioneer accelerator program
- **2023** — Co-founded E2B with Tomas Valenta; launched e2b.dev
- **2024** — Launched E2B SDK v1.0 and announced an $11.5M seed round; platform running millions of sandboxes per month
- **2025** — Raised a $21M Series A led by Insight Partners; E2B adopted by 88% of Fortune 100 companies

## Achievements

- Co-founded and leads E2B, adopted by 88% of Fortune 100 companies
- Raised $21M Series A led by Insight Partners (2025), bringing total funding to roughly $32M
- Built infrastructure that has run hundreds of millions of AI agent sandbox sessions
- Customers include Hugging Face, Perplexity, Groq, Manus, LMArena, Genspark and Lindy
- Grew an open-source project to thousands of GitHub stars within weeks of launch

## Latest updates

- **2025-07** — E2B raised a $21M Series A led by Insight Partners, with Decibel, Sunflower Capital, Kaya, and Docker's former CEO Scott Johnston participating; total funding reached about $32M.
- **2025-07** — E2B reported adoption by 88% of Fortune 100 companies and hundreds of millions of sandbox sessions.

## Links

- Website: https://e2b.dev
- LinkedIn: https://www.linkedin.com/in/mlejva/
- Twitter/X: https://x.com/mlejva
- GitHub: https://github.com/mlejva

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Profile page: https://yespress.io/vasek-mlejnsky
Published by YesPress — https://yespress.io
Last updated: 2026-07-24