Variables & Data

Set variables, access request data, and use expressions in your functions.

Variables & Data

Variables store data as your function runs. You create them with Set Variable steps and reference them in any step that follows.

The step properties panel showing variable configuration
Configure step properties and variables in the right panel

Set a variable

Use a Set Variable step to create or update a variable:

- Variable Name — e.g., greeting, totalPrice, isAdmin
- Value — An expression that computes the value

| Variable Name | Value                              |
|--------------|-------------------------------------|
| greeting   | "Hello, " + input.name          |
| totalPrice | input.price * input.quantity     |
| isAdmin    | vars.user.role === "admin"       |

Built-in variables

Every function has access to these built-in data sources:

| Variable  | What it contains                              | Example                    |
|-----------|----------------------------------------------|----------------------------|
| vars    | Variables you set during the function        | vars.cases               |
| input   | The request body (POST, PUT, PATCH)          | input.name               |
| params  | URL path parameters                          | params.id                |
| query   | URL query string parameters                  | query.page               |
| headers | HTTP request headers                         | headers.authorization    |
| env     | Server environment variables                 | env.JWT_SECRET           |

Examples

// Path: GET /api/cases/:id?include=updates
params.id          // "42"
query.include      // "updates"

// Body: POST /api/cases  { "case_name": "Contract Review" }
input.case_name    // "Contract Review"

// Environment
env.API_KEY        // Your configured API key

Good to know

Query string and path parameter values are always strings. Use params.id | toNumber or Number(params.id) when you need a number.

Using expressions

Expressions let you compute values dynamically. They use JavaScript syntax and work in any step property:

// Arithmetic
input.price * input.quantity

// String concatenation
"Hello, " + input.name

// Ternary
vars.count > 0 ? "found" : "empty"

// Access nested data
vars.user.address.city
vars.products[0].name

// Default values
input.page || 1
query.limit ? Number(query.limit) : 20

Filters

Filters transform values using a pipe (|) syntax. They are a shorthand for common operations:

input.email | lowercase | trim
query.page | toNumber | default: 1
vars.items | map: "name"
vars.name | uppercase

Pro tip

Check the Filters Reference for the full list of available filters.

Variable scoping

- Variables are scoped to the current function execution
- A variable set inside an If/Else branch is still accessible after the branch
- Each request creates a fresh context — variables do not leak between requests

Create a Function
/flows/creating-flows
Build your first function step by step
Code View
/flows/code-view
See variables as JavaScript code
Try & Runs
/flows/debugging
Inspect variable values at each step