Using JMESPath expressions

Use JMESPath expressions to map and transform JSON response from webhook action into the desired data structure.

Example of using JMESPath expression in your output attributes mapping

Be aware of the following:

• If your JMESPath expression is incorrect or points to non-existent fields, the output attribute value will be empty.

• If the resulting value of your JMESPath does not match the target attribute type, the attribute value will also be empty.

Resources on JMESPath:

• Official specification.

• Comprehensive examples.

• Tutorials.

Examples

Custom function: json_decode(...)

Webhook V2 supports a custom JMESPath function called json_decode(...).

Use it when an API returns JSON inside a string field and you need to read values from that encoded object.

Without json_decode(...), string fields are treated as plain text and cannot be traversed with dot notation.

Syntax:

json_decode(<json_string_field>)

You can combine it with normal JMESPath traversal, for example:

json_decode(payload).order.status

If the string is not valid JSON, the result is treated as empty for mapping purposes.

Example: extract values from a JSON-encoded field

Input JSON	JMESPath
{ "eventId": "evt_901", "payload": "{\"order\":{\"id\":\"ORD-1007\",\"status\":\"shipped\",\"tracking\":{\"carrier\":\"DHL\",\"number\":\"TRK-7788\"}}}" }	Expression: json_decode(payload).order.tracking.number Output: TRK-7788

Example: decode and return multiple fields

Input JSON	JMESPath
{ "payload": "{\"order\":{\"id\":\"ORD-1007\",\"status\":\"shipped\"}}" }	Expression: {order_id: json_decode(payload).order.id, order_status: json_decode(payload).order.status} Output: { "order_id": "ORD-1007", "order_status": "shipped" }

Select a Single Field

Input JSON	JMESPath
{ "name": "Alice", "age": 30, "city": "London" }	Expression: name Output: Alice

Access Nested Fields

Input JSON	JMESPath
{ "user": { "profile": { "name": "Charlie", "location": "London" } } }	Expression: user.profile.location Output: London

Select Multiple Fields

Input JSON	JMESPath
{ "id": 123, "name": "Bob", "email": "[email protected]", "age": 25 }	Expression: {name: name, email: email} Output: { "name": "Bob", "email": "[email protected]" }

Select all array element's properties

Input JSON	JMESPath
{ "products": [ {"name": "Laptop", "price": 999}, {"name": "Mouse", "price": 25}, {"name": "Keyboard", "price": 75} ] }	Expression: products[*].name Output: [ "Laptop", "Mouse", "Keyboard" ]

Filter array by condition

Input JSON	JMESPath
{ "items": [ {"name": "Apple", "price": 1.5, "inStock": true}, {"name": "Banana", "price": 0.8, "inStock": false}, {"name": "Orange", "price": 2.0, "inStock": true} ] }	Expression: items[?inStock == `true`] Output: [ {"name": "Apple", "price": 1.5, "inStock": true}, {"name": "Orange", "price": 2.0, "inStock": true} ]

Select root-level array

Input JSON	JMESPath
[ {"id": 1, "name": "Alice", "role": "admin"}, {"id": 2, "name": "Bob", "role": "user"}, {"id": 3, "name": "Charlie", "role": "user"} ]	Expression: @ Output: [ {"id": 1, "name": "Alice", "role": "admin"}, {"id": 2, "name": "Bob", "role": "user"}, {"id": 3, "name": "Charlie", "role": "user"} ]

Use bult-in functions

Input JSON	JMESPath
{ "items": [ {"name": "Apple", "price": 15 }, {"name": "Banana", "price": 999 }, {"name": "Orange", "price": 75 } ] }	Expression: max(products[*].price) Output: 999

Select array elements for a form message with dynamic data

You can create a from message with dynamic data retrieved from a webhook action. For example:

Input JSON	JMESPath
{ "products": [ {"sku": "LAP-001", "name": "Laptop", "price": 999}, {"sku": "MOU-002", "name": "Mouse", "price": 25}, {"sku": "KEY-003", "name": "Keyboard", "price": 75} ] }	Expression: products[*].{key: sku, value: name} Output: [ {"key": "LAP-001", "value": "Laptop"}, {"key": "MOU-002", "value": "Mouse"}, {"key": "KEY-003", "value": "Keyboard"} ]

This can then be used as a data source for your searchable select in a form message.