---
updatedAt: 2025-09-23T06:29:11.000Z
agentTools:
  projectIndex: https://developer.maximizer.com/llms.txt
---

# FormulaExpressionField

* Available Since API Version – 2.0

The FormulaExpressionField type is used to represent formula fields in Octopus API. FormulaExpressionField objects are read-only, and contain the following properties:

* **Rule -** A string value containing the formula expression. May be null or an empty string.

## Basic Read Request

The following example illustrates the syntax for a request for the default value of a FormulaExpressionField in a Read method call.

### Request

```
{
  "Formula":1
}

```

### Response

```
{
  "Formula":""
}

```

## Detailed Read Request

The following example illustrates the syntax for a request for all properties of a FormulaExpressionField in a Read method call.

### Request

```
{
  "Formula":{
    "Rule":1
  }
}

```

### Response

```
{
  "Formula":{
    "Rule":"[Budget\\Budget]-[Budget\\Costs]"
  }
}

```

## Create/Update Request

FormulaExpressionField objects are read-only and cannot be used in a Create or Update request.