A Code node is where you write your own logic inside a workflow. In n8n, that means you can do a transformation or rule that is too specific for the standard nodes.

This is powerful, but it comes with a cost: custom code is harder to maintain than configuration. Use it when it reduces complexity, not when it adds it.

Good reasons to use a Code node

• Business rules that do not fit a template: pricing logic, routing rules, scoring, or custom formatting that must be exact.
• Data cleanup at the boundary: normalize phone numbers, split names, standardize addresses, and enforce required fields before writing to your CRM.
• Complex transformations: merge multiple datasets, reshape nested JSON (structured data), or build a payload that an API requires.
• Custom validation: block bad input early and create clear error messages for staff.
• Integrations without a ready-made node: call a service by API when there is no native connector.

When it is usually the wrong choice

If the same result can be achieved with standard nodes, do that. Configuration is easier to review, easier to debug, and easier to hand off.

Also avoid code for tasks that change often. If sales ops changes the rule every week, you want the rule in a place that is easy to edit and safe to deploy.

How to keep Code nodes from becoming a liability

• Keep it small: one job per Code node, with clear input and output fields.
• Document assumptions: what fields must exist, what formats are expected, and what happens on failure.
• Log intentionally: log identifiers and outcomes, not sensitive data.
• Test the logic: keep sample inputs and expected outputs so changes do not break old behavior.

A realistic scenario

A lead arrives from a form with inconsistent fields. The Code node standardizes the phone number, maps “company size” into a numeric range, rejects missing consent, and then sends a clean payload to the CRM API. The sales team sees fewer duplicates and fewer “unknown” records, and reporting becomes reliable.