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

# Polar Built-In Types

Polar uses explicitly typed data. When you open a Polar policy, two main type categories are available:

| Class         | Description                                                                  |
| ------------- | ---------------------------------------------------------------------------- |
| **Primitive** | Literal values such as strings, integers, and booleans.                      |
| **Abstract**  | High-level types for modeling your application, such as users and resources. |

This page covers **built-in** types only. Most of your policy will be written using **custom types** defined as resource blocks.

## Primitive Types

Polar supports the following primitive types:

| Type      | Description           | Example |
| --------- | --------------------- | ------- |
| `String`  | Text value            | `"a"`   |
| `Integer` | 64-bit signed integer | `-3`    |
| `Boolean` | True or false values  | `true`  |

You can use primitives directly in rules or facts:

```polar theme={null}
is_string_a(x: String) if x = "a";
```

### Common Uses of `String`

By convention, Polar represents **permission names, role names**, and **relation names** as `String` values.

### Object Literal Representation

Primitives can also be expressed as object literals:

```polar theme={null}
Boolean{true}
```

This form has no semantic difference; it’s purely an alternate syntax.

### Fact Argument Length Limit

Each argument in a fact can be at most **384 bytes** (not characters—multi-byte characters reduce the count).\
Example within limits:
`has_relation(Foo{"<384-byte string>"}, "<384-byte-string>", Bar{"384-byte string>"})`

Polar provides two abstract types for authorization modeling:

| Type       | Description                                                                          |
| ---------- | ------------------------------------------------------------------------------------ |
| `Resource` | Something you protect (e.g. `Repository`, `Document`). Defined with `resource`.      |
| `Actor`    | Something you grant access to (e.g. `User`, `ServiceAccount`). Defined with `actor`. |

Create your own types by extending these abstracts in **resource blocks.**

### Polymorphism

Abstract types enable **polymorphism** in policies.

Among built-in types:

| Supertype  | Subtype |
| ---------- | ------- |
| `Resource` | `Actor` |

This means every `Actor` is also a `Resource`. See the [extends](/reference/polar/extends) documentation for details.

### Object Literal Restriction

Do **not** represent abstract types as object literals. For example, avoid:

`Resource{"foo"}` # Invalid