Expressions

Expressions let you pass data from one step to another without writing glue code. They use a {{nodeId.property}} syntax that is resolved at code generation time.

Syntax

{{nodeId.property}}
{{nodeId.nested.property}}
{{nodeId.arrayField[0].name}}

• nodeId — the ID of an upstream node (shown in the node config drawer)
• property — a dot-separated path into the node's output

Where expressions can be used

Expressions can be used in any config field of type string, expression, or textarea. They are also used in Branch conditions and Loop collection fields.

Field type	Expression support
string	Yes — embedded in the value, e.g. Hello {{user_step.name}}
expression	Yes — the entire value is an expression
textarea	Yes — embedded in multi-line text
number	No — use a Step node to compute numeric values
select	No — options are fixed at design time
secret	No — secrets bind to env vars, not upstream outputs
code	Yes — reference upstream vars directly by name in JavaScript

Examples

Passing an email address

In a Send Email node's "To" field:

{{create_user.email}}

This resolves to the email property of the create_user step's return value.

Nested property access

{{parse_webhook.body.order.id}}

Embedding in text

In a message body field:

Hello {{user.firstName}}, your order {{place_order.orderId}} has been confirmed.

How expressions resolve

At code-generation time, {{nodeId.property}} is replaced with a JavaScript property access on the step result variable:

// {{create_user.email}} becomes:
create_user.email

// {{parse_webhook.body.order.id}} becomes:
parse_webhook.body.order.id

Inside template literal strings (e.g. step names), expressions are wrapped in ${}:

await step.do(`Send email to ${create_user.email}`, async () => {
  /* ... */
})

Autocomplete

In config fields that support expressions, the UI provides autocomplete. After typing {{, a dropdown shows all upstream nodes and their typed output fields. Navigate with arrow keys and press Enter to insert.

The autocomplete tree mirrors the outputSchema of each node definition.

Validation

AwaitStep validates expressions at save time:

Error	Cause
References nonexistent node "x"	The node ID does not exist in the workflow
References downstream node "x"	The referenced node is not upstream (would create a cycle)
References the current node "x"	A node cannot reference its own output

TIP

Node IDs are auto-generated slugs like step_1, http_request_2. You can rename a node in its config drawer — the ID stays stable but the display name changes. The ID used in expressions is always the internal node ID, visible in the drawer's header.

Accessing the trigger payload

The trigger payload is available on event.payload inside Step node code. It is not available as an expression outside of Step nodes. To pass trigger data downstream as an expression, extract it in a Step node and return it:

// In a "Parse Trigger" step:
return {
  orderId: event.payload?.orderId,
  userId: event.payload?.userId,
}

Then reference {{parse_trigger.orderId}} in downstream nodes.