---
title: Custom Scalars Configuration
---

## Custom scalars configuration

You can specify a custom scalars configuration JSON file to map a custom scalar to a [JSON schema type](https://json-schema.org/understanding-json-schema/reference/type). The JSON file is an object with custom scalar names as keys and JSON schema types as values:

```json
{
  "MyCustomScalar": { "type": "string" }
}
```

Other than JSON schema type, an overriding description can also be provided. In the following example the description provided in the schema, `scalar description`, would get overridden by the description found in the custom scalar configuration file, `override description`:

```graphql
"""
scalar description
"""
scalar MyCustomScalar
```

```json
{
  "MyCustomScalar": { "type": "string", "description": "override description" }
}
```
