Jolt

1. Overview

The Jolt component (jolt-connector) transforms a JSON into another JSON shape, using a transformation specification written in the Jolt language (widely used to map data structures between different systems).

Use it when the flow needs to restructure a JSON — rename fields, change hierarchy, combine or split lists — without writing custom code. For simple transformations (a few fields), Add Variable may be easier to maintain.

2. Prerequisites

No external credentials — local processing.

3. Authentication and Connection

Not applicable.

4. Configuration / Supported Operations

The component has a single operation: transform a JSON using a Jolt spec.

Field	Required	Type	Description	Example
json	Yes	Text (JSON)	The input data to transform.	{"fullName": "Maria Silva"}
joltExpression	Yes	Text (JSON, Jolt spec)	The Jolt specification that defines how to transform the input json.	A Jolt spec (shift, default format, etc.)

5. Practical Examples

Simple example: rename a field of a received JSON.

Input (not used directly — the data comes from the json configuration field):

{
  "rawCustomer": { "fullName": "Maria Silva", "contactEmail": "maria@example.com" }
}

Component configuration:

{
  "componentName": "jolt-connector",
  "configurations": {
    "json": "{$.body.rawCustomer}",
    "joltExpression": "[{\"operation\": \"shift\", \"spec\": {\"fullName\": \"name\", \"contactEmail\": \"email\"}}]"
  }
}

Response:

{
  "response": {
    "name": "Maria Silva",
    "email": "maria@example.com"
  }
}

Advanced example: restructure a list of orders, extracting only the fields needed from each item.

Input:

{
  "orders": [
    { "orderId": 981, "customer": { "name": "Maria Silva" }, "totalAmount": 150.00 },
    { "orderId": 982, "customer": { "name": "John Smith" }, "totalAmount": 89.90 }
  ]
}

Component configuration:

{
  "componentName": "jolt-connector",
  "configurations": {
    "json": "{$.body.orders}",
    "joltExpression": "[{\"operation\": \"shift\", \"spec\": {\"*\": {\"orderId\": \"[&1].id\", \"customer.name\": \"[&1].customerName\", \"totalAmount\": \"[&1].amount\"}}}]"
  }
}

Response:

{
  "response": [
    { "id": 981, "customerName": "Maria Silva", "amount": 150.00 },
    { "id": 982, "customerName": "John Smith", "amount": 89.90 }
  ]
}

6. Common Errors and Troubleshooting

Error / Symptom	Likely Cause	How to Fix
"Required field 'json' is missing or null."	The json field wasn't filled in.	Fill in json with the data to transform.
"Required field 'joltExpression' is missing or null."	The joltExpression field wasn't filled in.	Fill in joltExpression with the transformation spec.
"Error during JOLT transformation: ..."	The Jolt spec is malformed, or isn't compatible with the input JSON's structure.	Review the Jolt spec's syntax and test it with the actual input data.
Result doesn't have the expected format	The Jolt spec doesn't cover all cases of the input JSON (e.g., missing fields in some items).	Adjust the Jolt spec to handle variations in the input data.