Expression engine environment variables#
File-based configuration
You can add _FILE to individual variables to provide their configuration in a separate file. Refer to Keeping sensitive data in separate files for more details.
Expressions are the JavaScript snippets n8n evaluates at runtime to set node parameters dynamically. The expression engine is the component that runs that evaluation. This page lists environment variables for configuring it.
Experimental
The vm engine is experimental. n8n runs the legacy engine by default. The variables below other than N8N_EXPRESSION_ENGINE only take effect when you set N8N_EXPRESSION_ENGINE to vm.
| Variable | Type | Default | Description |
|---|---|---|---|
N8N_EXPRESSION_ENGINE |
Enum string: legacy, vm |
legacy |
Which expression engine to use. legacy runs expressions without isolation. vm runs them in a sandboxed V8 isolate. vm is experimental; legacy remains the default. |
N8N_EXPRESSION_ENGINE_POOL_SIZE |
Number | 1 |
Number of V8 isolates kept warm in the pool. |
N8N_EXPRESSION_ENGINE_MAX_CODE_CACHE_SIZE |
Number | 1024 |
Maximum number of compiled expressions to cache. |
N8N_EXPRESSION_ENGINE_TIMEOUT |
Number | 5000 |
Execution timeout in milliseconds for each expression evaluation. |
N8N_EXPRESSION_ENGINE_MEMORY_LIMIT |
Number | 128 |
Memory limit in MiB for each V8 isolate. |
N8N_EXPRESSION_ENGINE_IDLE_TIMEOUT |
Number | - | If set, scales the isolate pool to zero warm isolates after this many seconds with no activity. |
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