--- layout: default title: Attributes parent: Deriving JsonSchema nav_order: 1 permalink: /deriving/attributes/ --- # Attributes You can add attributes to your types to customize Schemars's derived `JsonSchema` implementation. Serde also allows setting `#[serde(...)]` attributes which change how types are serialized, and Schemars will generally respect these attributes to ensure that generated schemas will match how the type is serialized by serde_json. `#[serde(...)]` attributes can be overriden using `#[schemars(...)]` attributes, which behave identically (e.g. `#[schemars(rename_all = "camelCase")]`). You may find this useful if you want to change the generated schema without affecting Serde's behaviour, or if you're just not using Serde. ## Table of Contents 1. [Supported Serde Attributes](#supported-serde-attributes) - [`rename`](#rename) - [`rename_all`](#rename_all) - [`tag` / `untagged`](#tag) - [`default`](#default) - [`skip`](#skip) - [`skip_serializing`](#skip_serializing) - [`skip_deserializing`](#skip_deserializing) - [`flatten`](#flatten) - [`with`](#with) 1. [Other Attributes](#other-attributes) - [Doc Comments (`doc`)](#doc) ## Supported Serde Attributes

`#[serde(rename = "name")]` / `#[schemars(rename = "name")]`

Set on a struct, enum, field or variant to use the given name in the generated schema instead of the Rust name. When used on a struct or enum, the given name will be used as the title for root schemas, and the key within the root's `definitions` property for subschemas. If set on a struct or enum with generic type parameters, then the given name may contain them enclosed in curly braces (e.g. `{T}`) and they will be replaced with the concrete type names when the schema is generated. Serde docs: [container](https://serde.rs/container-attrs.html#rename) / [variant](https://serde.rs/variant-attrs.html#rename) / [field](https://serde.rs/field-attrs.html#rename)

`#[serde(rename_all = "...")]` / `#[schemars(rename_all = "...")]`

Set on a struct, enum or variant to rename all fields according to the given case convention (see the Serde docs for details). Serde docs: [container](https://serde.rs/container-attrs.html#rename_all) / [variant](https://serde.rs/variant-attrs.html#rename_all)

`#[serde(tag = "type")]` / `#[schemars(tag = "type")]` / `#[serde(untagged)]` / `#[schemars(untagged)]`

Set on an enum to generate the schema for the [internally tagged](https://serde.rs/enum-representations.html#internally-tagged) or [untagged](https://serde.rs/enum-representations.html#untagged) representation of this enum. Schemars does not currently support the adjacently tagged representation ([#4](https://github.com/GREsau/schemars/issues/4)). Serde docs: [`tag`](https://serde.rs/container-attrs.html#tag) / [`untagged`](https://serde.rs/container-attrs.html#untagged)

`#[serde(default)]` / `#[schemars(default)]` / `#[serde(default = "path")]` / `#[schemars(default = "path")]`

Set on a struct or field to give fields a default value, which excludes them from the schema's `required` properties. The default will also be set on the field's schema's `default` property, unless it is skipped by a [`skip_serializing_if`](https://serde.rs/field-attrs.html#skip_serializing_if) attribute on the field. Any [`serialize_with`](https://serde.rs/field-attrs.html#serialize_with) or [`with`](https://serde.rs/field-attrs.html#with) attribute set on the field will be used to serialize the default value. Serde docs: [container](https://serde.rs/container-attrs.html#default) / [field](https://serde.rs/field-attrs.html#default)

`#[serde(skip)]` / `#[schemars(skip)]`

Set on a variant or field to prevent it from appearing in any generated schema. Serde docs: [variant](https://serde.rs/variant-attrs.html#skip) / [field](https://serde.rs/field-attrs.html#skip)

`#[serde(skip_serializing)]` / `#[schemars(skip_serializing)]`

Set on a field of a (non-tuple) struct to set the `writeOnly` property on that field's schema. Serde also allows this attribute on variants or tuple struct fields, but this will have no effect on generated schemas. Serde docs: [field](https://serde.rs/field-attrs.html#skip_deserializing)

`#[serde(skip_deserializing)]` / `#[schemars(skip_deserializing)]`

Set on a variant or field. When set on a field of a (non-tuple) struct, that field's schema will have the `readOnly` property set. When set on a variant or tuple struct field Schemars will treat this the same as a [`skip`](#skip) attribute. Serde docs: [variant](https://serde.rs/variant-attrs.html#skip_deserializing) / [field](https://serde.rs/field-attrs.html#skip_deserializing)

`#[serde(flatten)]` / `#[schemars(flatten)]`

Set on a field to include that field's contents as though they belonged to the field's container. Serde docs: [field](https://serde.rs/field-attrs.html#flatten)

`#[serde(with = "Type")]` / `#[schemars(with = "Type")]`

Set on a field to generate this field's schema as the given type instead of the field's actual type. Serde allows the `with` attribute to refer to any module path, but Schemars requires this to be an actual type which implements `JsonSchema`. Serde docs: [field](https://serde.rs/field-attrs.html#with)
## Other Attributes

Doc Comments (`#[doc = "..."]`)

If a struct, variant or field has any [doc comments](https://doc.rust-lang.org/stable/rust-by-example/meta/doc.html#doc-comments) (or [`doc` attributes](https://doc.rust-lang.org/rustdoc/the-doc-attribute.html)), then these will be used as the generated schema's `description`. If the first line is an ATX-style markdown heading (i.e. it begins with a # character), then it will be used as the schema's `title`, and the remaining lines will be the `description`.