Templates and variables

Any text setting on a block (a message, a URL, a JSON body, an email subject) can include variables in double curly braces. They are filled in when the block runs.

The three forms

Customer {{input.email}} wrote:{{input.message}}Category: {{steps.classify_1.output}}Order: {{steps.extract_1.output.order_id}}Previous step: {{last.output}}

Reading into JSON

Add .key segments to walk into objects, and numbers to pick list items: {{input.order.items.0.sku}} reads the first item's SKU from a webhook body. Extract blocks always output JSON, so their fields are {{steps.extract_1.output.order_id}}. HTTP request blocks pass the response on; when it is JSON you can read it by key the same way.

Input rules

• Start fields are text. Numbers and true/false are turned into text; an object or a list in a Start field is refused.
• Required fields can't be empty. The run stops with an error like Fill in "message" to run this workflow.
• Webhook runs keep extra keys that aren't Start fields, so you can read nested JSON, up to 5 levels deep and 500 values.
• All of a run's input together is at most 32,000 characters.