# facet-json-schema
[](https://coveralls.io/github/facet-rs/facet?branch=main)
[](https://crates.io/crates/facet-json-schema)
[](https://docs.rs/facet-json-schema)
[](./LICENSE)
[](https://discord.gg/JhD7CwCJ8F)
# facet-json-schema
Generate [JSON Schema](https://json-schema.org/) from facet type metadata.
This crate uses facet's reflection capabilities to generate JSON Schema definitions
from any type that implements `Facet`. The generated schemas can be used for:
- API documentation (OpenAPI/Swagger)
- Runtime validation
- Cross-language type generation
- Editor autocompletion
## Usage
```rust
use facet::Facet;
use facet_json_schema::to_schema;
#[derive(Facet)]
struct User {
name: String,
age: u32,
email: Option<String>,
}
let schema = to_schema::<User>();
println!("{}", schema);
```
## Output
```json
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"name": { "type": "string" },
"age": { "type": "integer", "minimum": 0, "maximum": 4294967295 },
"email": { "type": "string" }
},
"required": ["name", "age"]
}
```
## LLM contribution policy
## Sponsors
Thanks to all individual sponsors:
<p> <a href="https://github.com/sponsors/fasterthanlime">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/github-dark.svg">
<img src="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/github-light.svg" height="40" alt="GitHub Sponsors">
</picture>
</a> <a href="https://patreon.com/fasterthanlime">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/patreon-dark.svg">
<img src="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/patreon-light.svg" height="40" alt="Patreon">
</picture>
</a> </p>
...along with corporate sponsors:
<p> <a href="https://aws.amazon.com">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/aws-dark.svg">
<img src="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/aws-light.svg" height="40" alt="AWS">
</picture>
</a> <a href="https://zed.dev">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/zed-dark.svg">
<img src="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/zed-light.svg" height="40" alt="Zed">
</picture>
</a> <a href="https://depot.dev?utm_source=facet">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/depot-dark.svg">
<img src="https://github.com/facet-rs/facet/raw/main/static/sponsors-v3/depot-light.svg" height="40" alt="Depot">
</picture>
</a> </p>
...without whom this work could not exist.
## Special thanks
The facet logo was drawn by [Misiasart](https://misiasart.com/).
## License
Licensed under either of:
- Apache License, Version 2.0 ([LICENSE-APACHE](https://github.com/facet-rs/facet/blob/main/LICENSE-APACHE) or <http://www.apache.org/licenses/LICENSE-2.0>)
- MIT license ([LICENSE-MIT](https://github.com/facet-rs/facet/blob/main/LICENSE-MIT) or <http://opensource.org/licenses/MIT>)
at your option.