Fastify Integration

json-rest-api now ships a Fastify-oriented connector:

import fastify from 'fastify'
import {
  RestApiPlugin,
  RestApiKnexPlugin,
  FastifyPlugin
} from 'json-rest-api'

const app = fastify()

await api.use(RestApiPlugin, {
  simplifiedApi: false,
  simplifiedTransport: false
})

await api.use(RestApiKnexPlugin, { knex })

await api.use(FastifyPlugin, {
  app,
  mountPath: '/api'
})

What the connector does

The Fastify connector listens to the same addRoute hook as the Express connector and registers the generated REST routes on the Fastify instance you pass in pluginOptions.app.

It also consumes the transport schema exported by json-rest-schema before the request reaches the resource method:

• POST routes use the schema export in create mode
• PUT routes use the schema export in replace mode
• PATCH routes use the schema export in patch mode
• relationship POST / PATCH / DELETE routes use JSON:API relationship document schemas

Those field schemas are wrapped in the JSON:API document envelope expected by json-rest-api.

What gets rejected early

Fastify can now stop malformed write payloads before they reach the app layer:

• missing data
• invalid data.type
• invalid data.id on PUT / PATCH
• malformed attribute payloads
• unknown attribute fields
• invalid scalar types according to the resource schema
• malformed relationship write documents

The transport schema also reflects the existing write contract:

• output-only computed fields are removed from data.attributes
• direct belongsTo foreign keys are removed from data.attributes
• relationship linkage still belongs under data.relationships

This keeps Fastify transport validation aligned with the same transport rules already enforced by the runtime methods.

Content types

The connector registers an application/vnd.api+json parser and rejects unsupported write content types before the route handler runs.

Accepted write content types are:

• application/vnd.api+json
• application/json

Scope

This connector is intentionally narrow:

• it uses the exported schema already owned by json-rest-schema
• it does not add a JSKIT-specific compatibility layer
• it does not move business validation out of the resource methods

The goal is transport-level shape rejection, not a second validation system.