E2B, founded in 2023 by longtime friends Vaclav Mlejnsky and Tomas Valenta while studying together in the Czech Republic, builds isolated cloud sandboxes where an AI agent can execute code, run a full development environment, or test its own output safely, without that code touching a shared production system.
That safety boundary matters more as agents move from answering questions to actually writing and running code on a company's behalf: E2B reports that 88% of Fortune 100 companies now use its sandboxes, and the company raised a $21 million Series A led by Insight Partners in July 2025, with participation from Decibel and Sunflower Capital, on top of prior seed funding.
Pricing is usage-based around sandbox compute time and concurrency, with a free tier for initial building and testing before scaling into paid usage. For a developer building an AI agent that needs to execute code or run commands autonomously, without that execution touching production infrastructure directly, E2B's isolated sandbox layer addresses that directly.
