---
title: "n8n Expression Syntax - Air Market"
description: "You are filling in a field in n8n that needs a value from an earlier step, and the little expression you type keeps coming out wrong. This checks that syntax and helps you fix the usual mistakes. Rea…"
canonical: "https://airmarket.ai/app/n8n-expression-syntax"
---

[Air Market](/) / [Automation](/category/automation) / n8n Expression Syntax

Skill by [Romuald Członkowski](/@czlonkowski)

# n8n Expression Syntax

Get the data from the last node into this field, correctly

## What this does

You are filling in a field in n8n that needs a value from an earlier step, and the little expression you type keeps coming out wrong. This checks that syntax and helps you fix the usual mistakes. Reach for it any time one node's field depends on another node's data.

### Top 3 things it does for you

- Write an expression that reads a previous node's data
- Fix an expression that keeps erroring
- Map fields between two nodes

## Information

**n8n Expression Syntax at a glance**

|  |  |
| --- | --- |
| Kind | Skill |
| Publisher | [Romuald Członkowski](/@czlonkowski) |
| Category | [Automation](/category/automation) |
| Works with | Agent Skills - an open standard supported by 40+ agents |
| Size | 36 KB |
| Licence | MIT |
| Repository | [czlonkowski/n8n-skills](https://github.com/czlonkowski/n8n-skills/tree/9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25/skills/n8n-expression-syntax) |
| GitHub stars | 6,119 (as of Nov 2026) |
| Installs | 6,875, counted by skills.sh (Nov 2026) |

## Security report

**Verified.** AIR scanned this exact version of n8n Expression Syntax and flagged nothing. AIR's verdict: **safe**.

**What n8n Expression Syntax's check was run against**

|  |  |
| --- | --- |
| Commit | 9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25 |
| Content hash | ad73ac3a7100d868a7a66b421af5907a674cd89106d52972fe748c98e02c4836 |
| Files read | [Browse the files at this exact commit](https://github.com/czlonkowski/n8n-skills/blob/9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25/skills/n8n-expression-syntax/SKILL.md) |

A scan is named by the exact content it read, not by a version number. A different version is a different artifact, and nothing here applies to a version AIR has not scanned.

[Read the full security report for n8n Expression Syntax](/security/n8n-expression-syntax)

## About n8n Expression Syntax

This validates n8n expression syntax and fixes common errors. It applies when you are writing expressions, using the curly brace syntax, accessing the JSON and node variables, troubleshooting expression errors, mapping data between nodes, or referencing webhook data.

Reach for it whenever you configure a node field that references data from a previous node. Expressions are how n8n passes data between nodes, and getting the syntax wrong is the most common source of workflow errors. It also answers whether a complex expression hurts performance.

## What's inside

- SKILL.md - instructions
- COMMON_MISTAKES.md - reference
- EXAMPLES.md - reference
- README.md - reference

## Questions

### Is n8n Expression Syntax safe to install?

AIR scanned this exact version of n8n Expression Syntax and flagged nothing. AIR's verdict: safe. The verdict is named by the content that was read, at commit 9ea3aa58cff2, so it cannot drift onto a version nobody scanned. The full report is at https://airmarket.ai/security/n8n-expression-syntax.

### How do I install n8n Expression Syntax?

Open https://airmarket.ai/app/n8n-expression-syntax on Air Market and use the install action: Air Market hands Claude a prompt naming this exact skill, and Claude sets it up. Source, pinned to the exact commit this listing describes: https://github.com/czlonkowski/n8n-skills/tree/9ea3aa58cff22ad9a014b402dea5b8bd03c8ae25/skills/n8n-expression-syntax. Install from that link, not the branch.

## Related on Air Market

- [More Automation listings](/category/automation)
- [Everything by Romuald Członkowski](/@czlonkowski)

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Canonical URL: <https://airmarket.ai/app/n8n-expression-syntax>