parse once
Cached parsing and validation
Query parsing and validation results are cached, so repeated operations skip straight to execution.
Mercurius v16.10.1 · Fastify 5
GraphQL, at Fastify speed.
Mercurius is a GraphQL adapter for Fastify. Register the plugin, hand it a schema and resolvers, and you get cached parsing, automatic loaders, a JIT executor, subscriptions and federation out of the box.
Read the docs
$
npm i fastify mercurius graphql- downloads / mo
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- license
- MIT
'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 })
'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 })Run it, then open http://localhost:3000/graphiql.
// core features
Everything a production GraphQL server needs
Mercurius sits on the Fastify plugin system, so hooks, decorators and encapsulation work exactly the way they do in the rest of your app.
no 1 + N
Loaders built in
Automatic loader integration batches nested resolvers and avoids the 1 + N query problem without extra wiring.
graphql-jit
Just-In-Time compiler
Resolvers are compiled with graphql-jit for execution that is much faster than the reference graphql-js executor.
over WebSocket
Subscriptions
First-class subscriptions with graphql-ws and subscriptions-transport-ws, including custom pub/sub backends.
@mercuriusjs/*
Federation and gateway
Build Apollo-compatible federated services with @mercuriusjs/federation, and compose them with @mercuriusjs/gateway, subscriptions included.
fewer round trips
Batched and persisted queries
Accept batched operations in a single request and configure persisted queries to cut payload size on the wire.
// ecosystem
Grows with your graph
Start with a single server, split it into federated services later. Type-safety, testing and tracing are covered by the companion packages and the documented integrations.
Browse all integrations- @mercuriusjs/federationExpose a service as an Apollo Federation subgraph, subscriptions included.
- @mercuriusjs/gatewayCompose federated services into a single graph with a Mercurius gateway.
- mercurius-integration-testingRun queries and subscriptions against your app in tests without a network.
- mercurius-codegenGenerate TypeScript types for your schema, resolvers and operations.
// acknowledgements
The project is kindly sponsored by
Ship your first query
Start from the introduction, browse the examples, or open a good first issue if you'd rather contribute.