---
title: 'Set Variable'
description: 'Store a computed or referenced value for later nodes to read.'
---
# Set Variable

Writes a value into the workflow execution context under a named key.
Downstream nodes can then reference `{{<this_node_id>.data.value}}` to read it.

## When to use

- You need to compute a value once and reuse it in multiple downstream nodes.
- You want to give an opaque chain of references a friendlier name to
  reference later (e.g. compute a customer ID in node A and read it
  everywhere else as `{{customer_id.data.value}}`).
- You're stitching together values from multiple upstream nodes into a
  single place.

## Configuration

| Field | Required | What it does |
|---|---|---|
| `key` | Yes | Logical name of the variable. Used for readability only — downstream refs use the node ID, not the `key`. |
| `value` | — | Any static or referenced value. Supports full `{{...}}` syntax including arithmetic on referenced numbers. |

## What it outputs

```
{
  key: "customer_id",
  value: <whatever you set>
}
```

Downstream references use the node ID: `{{<node_id>.data.value}}`.

## When NOT to use it

If you only need the value in one downstream node, just reference the
source directly with `{{upstream_node.data.path}}`. Set Variable is for
*sharing* a value across multiple downstream consumers.

For transforming a value into a new shape, use **Transform** — it's
purpose-built for field mapping, whereas Set Variable just stores
whatever value you give it.