How Can I Reliably Pass Variables Between Disconnected Nodes in n8n?

Below is an explanation of how you can reliably share and persist variables across nodes in your workflow.

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Use Workflow Static Data

n8n provides a mechanism specifically designed for storing and accessing data within a workflow—the “Workflow static data.” Unlike regular node output, this data is stored regardless of the main execution path. If you try to use a disconnect Set node or reference a node’s output that isn’t executed because of flow separation, you can end up with undefined values. Workflow static data was designed to overcome this limitation.

For example, instead of using a disconnected Set node, you can write a Code node that saves needed data into the workflow’s static data:

JAVASCRIPTCopied
// Store data which is then accessible through the workflow
const staticData = this.getWorkflowStaticData('node');
staticData.myVariable = 'value';
return items;

Later, in any node (that runs as part of the execution), you can retrieve it:

JAVASCRIPTCopied
// Retrieve the stored variable
const staticData = this.getWorkflowStaticData('node');
const value = staticData.myVariable;
return [{ json: { myVariable: value } }];

This method will persist your data independently of the execution path, allowing you to reference it reliably.

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A Note on Custom Variables

While you might have thought about storing values with a custom variable (using $vars.), custom variables in n8n are read-only and must be set via the UI. They cannot be dynamically written to during workflow execution. Therefore, they won’t serve your need if the variable values are determined at runtime.

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Best Practices

• Restructure if Possible: Ensure that nodes producing data you need are part of a connected execution flow. If not, using workflow static data is your safest bet.

• Handling Disconnected Nodes: If your design forces you to have nodes outside the main flow (perhaps for organizational reasons), make sure that when they run they write to the workflow static data, then any subsequent node can safely reference that information.

• Error Handling: Remember to check for undefined values when reading from static data, as workflows won’t automatically fail if a value isn’t present.

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By using Workflow static data, you ensure that your dynamically generated values persist and can be accessed reliably later in the workflow—even if the node setting those values isn’t directly connected to the node that later uses them.

I hope this helps clarify the best approach for passing variables between disconnected nodes in n8n. Let me know if you have any further questions!