5. Variables & Expressions

Use n8n's expression language for dynamic data.

20m Lesson 5 of 6

n8n's expression system gives you access to powerful built-in functions and variables that make your workflows dynamic and flexible.

Built-in Variables

- `$json` — Current item's JSON data
- `$binary` — Current item's binary data
- `$env` — Environment variables
- `$workflow` — Workflow metadata (id, name, active)
- `$execution` — Current execution metadata
- `$now` — Current timestamp
- `$today` — Current date (start of day)

Code Examples

Built-in Functions

javascript

// String functions
{{ $json.name.toUpperCase() }}
{{ $json.email.includes("@gmail") }}
{{ $json.text.replace(/\n/g, "<br>") }}

// Date functions (Luxon)
{{ $now.toFormat("yyyy-MM-dd") }}
{{ $now.minus({ days: 7 }).toISO() }}
{{ DateTime.fromISO($json.date).diffNow("days").days }}

// Array functions
{{ $json.tags.includes("urgent") }}
{{ $json.scores.reduce((a,b) => a+b, 0) / $json.scores.length }}

// Workflow variables
{{ $workflow.name }}
{{ $execution.id }}

Pro Tips

💡Use $env to store API keys and configuration that changes between environments

Comprehension Quiz

Answer 2 of 2 correctly to unlock lesson completion.

1. What does $now return in n8n?

2. How do you access environment variables in expressions?

Pass the quiz above to unlock lesson completion

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All lessons in this chapter

1. Workflow Anatomy15m 2. Trigger Types Explained20m 3. Data Flow & Mapping20m 4. Error Handling Basics15m 5. Variables & Expressions20m 6. Workflow Organization & Best Practices20m