Introduction

Mercurius is a GraphQL adapter for Fastify

Features:

Caching of query parsing and validation.
Automatic loader integration to avoid 1 + N queries.
Just-In-Time compiler via graphql-jit.
Subscriptions.
Federation support via @mercuriusjs/federation, including Subscriptions.
Gateway implementation via @mercuriusjs/gateway, including Subscriptions.
Batched query support.
Customisable persisted queries.

Install

npm i fastify mercurius graphql
# or
yarn add fastify mercurius graphql

The previous name of this module was fastify-gql (< 6.0.0).

Quick Start

'use strict'

const Fastify = require('fastify')
const mercurius = require('mercurius')

const app = Fastify()

const schema = `
  type Query {
    add(x: Int, y: Int): Int
  }
`

const resolvers = {
  Query: {
    add: async (_, { x, y }) => x + y
  }
}

app.register(mercurius, {
  schema,
  resolvers
})

app.get('/', async function (req, reply) {
  const query = '{ add(x: 2, y: 2) }'
  return reply.graphql(query)
})

app.listen({ port: 3000 })

Examples

Check GitHub repo for more examples.