# Untitled string in Extending Schema

```txt
https://example.com/schemas/extending#/allOf/1/properties/id
```

A unique identifier given to every addressable thing.


| Abstract            | Extensible | Status         | Identifiable            | Custom Properties | Additional Properties | Access Restrictions | Defined In                                                                                   |
| :------------------ | ---------- | -------------- | ----------------------- | :---------------- | --------------------- | ------------------- | -------------------------------------------------------------------------------------------- |
| Can be instantiated | No         | Unknown status | Unknown identifiability | Forbidden         | Allowed               | none                | [extending.schema.json\*](../generated-schemas/extending.schema.json "open original schema") |

## id Type

`string`

## id Constraints

**URI reference**: the string must be a URI reference, according to [RFC 3986](https://tools.ietf.org/html/rfc4291 "check the specification")