vitest/docs/config/isolate.md

title	outline
isolate | Config	deep

isolate

• Type: boolean
• Default: true
• CLI: --no-isolate, --isolate=false

Run tests in an isolated environment. This option has no effect on vmThreads and vmForks pools.

Disabling this option might improve performance if your code doesn't rely on side effects (which is usually true for projects with node environment).

::: tip You can disable isolation for specific test files by using Vitest workspaces and disabling isolation per project. :::