> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apinizer.com/llms.txt
> Use this file to discover all available pages before exploring further.

# JSON Body Enrichment

> Step-by-step guide for creating a complex enriched JSON body by combining request body, headers, query parameters, context variables, and custom intermediate variables.

## Scenario

This guide uses the classic **Pet Store** example to build a fully enriched output JSON by combining the following sources:

* Request body fields (JSONPath)
* Two request headers (`Content-Type`, `X-Request-Id`)
* A query parameter (`format`)
* Context variables (HTTP method, client IP, correlation ID, year, date-time, environment)
* JEXL ternary expressions (conditional operation type, computed summary)
* Custom intermediate variables (`petName`, `categoryLabel`, `statusLabel`, `nestedObject`)

### Input Request

```json theme={null}
{
  "id": 1,
  "category": { "id": 10, "name": "Canine" },
  "name": "Buddy",
  "photoUrls": ["https://example.com/buddy.jpg"],
  "tags": [{ "id": 5, "name": "friendly" }],
  "status": "available"
}
```

***

## Step 1: Extract Intermediate Custom Variables

### Row 1 — Pet Name

| Field         | Value                       |
| ------------- | --------------------------- |
| Build Mode    | Template                    |
| Template      | `#{body.$.name}`            |
| Target        | Custom Variable → `petName` |
| Default Value | `unknown`                   |

### Row 2 — Category Label

| Field         | Value                             |
| ------------- | --------------------------------- |
| Build Mode    | Template                          |
| Template      | `#{body.$.category.name}`         |
| Target        | Custom Variable → `categoryLabel` |
| Default Value | `uncategorized`                   |

### Row 3 — Status Label

| Field         | Value                                                                                             |
| ------------- | ------------------------------------------------------------------------------------------------- |
| Build Mode    | Template                                                                                          |
| Template      | `#{body.$.status == 'available' ? 'AVAILABLE' : body.$.status == 'pending' ? 'PENDING' : 'SOLD'}` |
| Target        | Custom Variable → `statusLabel`                                                                   |
| Default Value | `UNKNOWN`                                                                                         |

***

## Step 2: Conditional Nested Object

### Row 4 — Default (null)

| Field      | Value                            |
| ---------- | -------------------------------- |
| Build Mode | Template                         |
| Template   | `null`                           |
| Target     | Custom Variable → `nestedObject` |

### Row 5 — Available Status Override

| Field         | Value                                                                            |
| ------------- | -------------------------------------------------------------------------------- |
| Row Condition | `request.body.$.status == 'available'`                                           |
| Build Mode    | Template                                                                         |
| Template      | `{"displayName":"#{petName} - #{categoryLabel}","statusLabel":"#{statusLabel}"}` |
| Target        | Custom Variable → `nestedObject`                                                 |

<Warning>
  The template above contains `{` and `}` characters, which are nested curly braces inside the `#{}` expression block. The balanced brace scanner in the Message Builder correctly handles this without breaking the parsing.
</Warning>

***

## Step 3: Final Body Template

### Row 6 — Build Enriched JSON

```
{"request":{"headers":{"contentType":"#{header.Content-Type}","xRequestId":"#{header.X-Request-Id}"},"query":{"format":"#{query.format}"},"body":{"id":#{body.$.id},"name":"#{petName}","category":{"id":#{body.$.category.id},"name":"#{categoryLabel}","nested":#{nestedObject}},"photoUrls":#{body.$.photoUrls},"tags":#{body.$.tags},"status":"#{body.$.status}"}},"context":{"httpMethod":"#{context.request.httpMethod}","clientIp":"#{context.request.remoteAddress}","correlationId":"#{context.message.correlationId}","year":"#{context.system.year}","dateTime":"#{context.system.dateTime}","environment":"#{context.environment.name}"},"computed":{"operationType":"#{context.request.httpMethod == 'POST' ? 'create' : context.request.httpMethod == 'PUT' ? 'update' : context.request.httpMethod == 'DELETE' ? 'delete' : 'read'}","summary":"#{petName} (#{categoryLabel}) - #{statusLabel}"}}
```

| Field         | Value                               |
| ------------- | ----------------------------------- |
| Build Mode    | Template                            |
| Template      | Template above                      |
| Target        | Custom Variable → `enrichedPayload` |
| Default Value | `{}`                                |

***

## Expected Output

```json theme={null}
{
  "request": {
    "headers": {
      "contentType": "application/json",
      "xRequestId": "abc-123"
    },
    "query": {
      "format": "full"
    },
    "body": {
      "id": 1,
      "name": "Buddy",
      "category": {
        "id": 10,
        "name": "Canine",
        "nested": {
          "displayName": "Buddy - Canine",
          "statusLabel": "AVAILABLE"
        }
      },
      "photoUrls": ["https://example.com/buddy.jpg"],
      "tags": [{ "id": 5, "name": "friendly" }],
      "status": "available"
    }
  },
  "context": {
    "httpMethod": "POST",
    "clientIp": "192.168.1.1",
    "correlationId": "8260e8b4-29d7-479a-8266-5dbb29c0d0fa",
    "year": "2026",
    "dateTime": "2026-02-20T10:35:48.000Z",
    "environment": "production"
  },
  "computed": {
    "operationType": "create",
    "summary": "Buddy (Canine) - AVAILABLE"
  }
}
```

***

## Key Points

| Topic                          | Note                                                     |
| ------------------------------ | -------------------------------------------------------- |
| **Number fields**              | Do not wrap in quotes: `"id":#{body.$.id}`               |
| **Array fields**               | Do not wrap in quotes: `"photoUrls":#{body.$.photoUrls}` |
| **Conditional JSON object**    | Manage via custom variable + row condition               |
| **Custom variable references** | Use directly: `#{petName}`, `#{statusLabel}`             |
| **Nested `{}`**                | The balanced brace scanner handles them correctly        |

<Tip>
  Define intermediate custom variables first, then use them in the final template. This approach keeps the template clean and maintainable.
</Tip>