n8n-expression-syntax

Expert guide for writing correct n8n expressions in workflows. All dynamic content in n8n uses double curly braces : Examples : Access data from the current node: Access data from any previous node: Important : Access current date/time: Access environment variables: Most Common Mistake : Webhook data is NOT at the root! Why : Webhook node wraps incoming data under .body property to preserve headers, params, and query parameters. Code nodes use direct JavaScript access , NOT expressions! Expressions must be wrapped in double curly braces. Field or node names with spaces require bracket notation : Node references are case-sensitive : Don't double-wrap expressions: For complete error catalog with fixes, see COMMON_MISTAKES.md For real workflow examples, see EXAMPLES.md Webhook receives : In Slack node text field : HTTP Request returns : In Email node (reference HTTP Request): "Cannot read property 'X' of undefined" → Parent object doesn't exist → Check your data path "X is not a function" → Trying to call method on non-function → Check variable type Expression shows as literal text → Missing {{ }} → Add curly braces String : Array : DateTime (Luxon): Number : Essential Rules : Most Common Mistakes : For more details, see: Need Help? Reference the n8n expression documentation or use n8n-mcp validation tools to check your expressions. - Node names must be in quotes - Node names are...