`app.addSchema()`

Registers a shared JSON Schema that routes can reference by $id.

Since Fastify 5 Spec ↗

Syntax

app.addSchema(schema: object)

Parameters

Name	Type	Required	Description
`schema`	`object`	No	A JSON Schema object with a unique $id.

Returns

FastifyInstance — The instance, for chaining.

Throws

FastifyError — Thrown if a schema with the same $id is already added.

Examples

import Fastify from 'fastify';

const app = Fastify();

app.addSchema({
  $id: 'cat',
  type: 'object',
  properties: { id: { type: 'integer' }, name: { type: 'string' } },
});

app.post('/cats', {
  schema: { body: { $ref: 'cat#' } },
}, async (req) => req.body);

Notes

Shared schemas are referenced with `$ref: 'id#'` or `$ref: 'id#/properties/name'`. They are scoped to the encapsulation context in which they are added.