---
title: "What is snapshot fork?"
description: "A snapshot fork creates a new environment from an already-warm one that has finished installing and building, so it costs milliseconds rather than seconds."
url: "https://www.promigence.ai/glossary/snapshot-fork"
site: "Promigence"
---

# What is snapshot fork?

A snapshot fork creates a new environment from an already-warm one that has finished installing and building, so it costs milliseconds rather than seconds.

The alternative is booting a machine, cloning a repo, installing dependencies and building it: 60 to 100 seconds of identical work, repeated on every episode. A fork skips all of it. The parent is already built, already warm, and the copy starts from there.

A Promigence copy is ready for its first command 39 ms in, and a hundred at once still land at 122 ms.

## Related
- https://www.promigence.ai/glossary/warm-start