Express Integration

Learn how to integrate Feathers with Express for HTTP/REST APIs with middleware support

The @feathersjs/express package provides seamless integration between Feathers and Express, combining the power of Feathers services with Express’s rich middleware ecosystem.

Installation

npm install @feathersjs/express express

Basic Setup

1. Create the Express application

   The Express integration wraps a Feathers application with Express functionality:

   import { feathers } from '@feathersjs/feathers'
   import express from '@feathersjs/express'
   
   const app = express(feathers())
   
2. Configure REST transport

   Enable the REST transport to expose services via HTTP:

   import { rest } from '@feathersjs/express'
   
   app.configure(rest())
   
3. Register services

   Services are automatically exposed as REST endpoints:

   app.use('/users', {
     async find() {
       return [{ id: 1, name: 'Alice' }]
     },
     async get(id) {
       return { id, name: 'Alice' }
     }
   })
   
4. Add error handling

   Use built-in error handlers for production-ready error responses:

   import { errorHandler, notFound } from '@feathersjs/express'
   
   app.use(notFound())
   app.use(errorHandler())
   
5. Start the server

   The listen method automatically calls setup() on all services:

   await app.listen(3030)
   console.log('Feathers app started on http://localhost:3030')
   

Complete Example

import { feathers } from '@feathersjs/feathers'
import express, {
  rest,
  json,
  urlencoded,
  cors,
  errorHandler,
  notFound
} from '@feathersjs/express'

const app = express(feathers())

// Enable CORS, body parsing and compression
app.use(cors())
app.use(json())
app.use(urlencoded({ extended: true }))

// Configure REST transport
app.configure(rest())

// Register services
app.use('/messages', {
  async find() {
    return [
      { id: 1, text: 'Hello world' },
      { id: 2, text: 'How are you?' }
    ]
  },
  async create(data) {
    return { id: 3, ...data }
  }
})

// Error handling
app.use(notFound())
app.use(errorHandler())

// Start server
const server = await app.listen(3030)
console.log('Server ready on http://localhost:3030')

Service Middleware

You can add Express middleware before and after service calls:

import { Request, Response, NextFunction } from 'express'

const logRequest = (req: Request, res: Response, next: NextFunction) => {
  console.log(`${req.method} ${req.url}`)
  next()
}

const addTimestamp = (req: Request, res: Response, next: NextFunction) => {
  res.data = { ...res.data, timestamp: new Date() }
  next()
}

// Middleware runs before service method, then after
app.use('/todos',
  logRequest,              // before middleware
  todoService,             // the service
  addTimestamp,            // after middleware
  { methods: ['find', 'get', 'create'] }
)

How Middleware Works

Before Middleware

Middleware added before the service runs before the service method is called:

const validateAuth = (req, res, next) => {
  if (!req.headers.authorization) {
    return res.status(401).json({ error: 'Unauthorized' })
  }
  next()
}

app.use('/protected', validateAuth, protectedService)

After Middleware

Middleware added after the service has access to res.data with the service result:

const formatResponse = (req, res, next) => {
  // Modify the service result
  res.data = {
    status: 'success',
    data: res.data,
    timestamp: new Date()
  }
  next()
}

app.use('/api/users', userService, formatResponse)

Authentication

Integrate Feathers authentication with Express middleware:

import { authenticate } from '@feathersjs/express'

// Protect specific routes
app.use('/admin',
  authenticate('jwt'),
  adminService
)

// Or use as route middleware
app.get('/profile',
  authenticate('jwt'),
  (req, res) => {
    res.json({ user: req.feathers.user })
  }
)

Authentication Settings

import { rest, parseAuthentication } from '@feathersjs/express'

// Configure REST with authentication parsing
app.configure(rest({
  authentication: {
    service: 'authentication',
    strategies: ['jwt', 'local']
  }
}))

// Or add globally
app.use(parseAuthentication({
  strategies: ['jwt']
}))

Error Handling

The Express integration provides comprehensive error handling:

Default Handler

import { errorHandler } from '@feathersjs/express'

// Use default error handler (recommended)
app.use(errorHandler())

Not Found Handler

import { notFound } from '@feathersjs/express'

// Simple 404
app.use(notFound())

// Verbose mode includes the URL in error message
app.use(notFound({ verbose: true }))

Static Files

Serve static files using Express’s static middleware:

import { serveStatic } from '@feathersjs/express'
import path from 'path'

// Serve static files from public directory
app.use('/', serveStatic(path.join(__dirname, 'public')))

// Or use Express directly
import express from 'express'
app.use('/assets', express.static('assets'))

Custom Response Formatting

Customize how service results are sent as HTTP responses:

import { rest, RequestHandler } from '@feathersjs/express'

const customFormatter: RequestHandler = (req, res, next) => {
  if (res.data === undefined) {
    return next()
  }

  // Custom formatting logic
  res.format({
    'application/json': () => {
      res.json({
        success: true,
        result: res.data,
        timestamp: Date.now()
      })
    },
    'text/html': () => {
      res.send(`<pre>${JSON.stringify(res.data, null, 2)}</pre>`)
    }
  })
}

app.configure(rest({ formatter: customFormatter }))

Using Existing Express App

You can integrate Feathers into an existing Express application:

import express from 'express'
import feathersExpress from '@feathersjs/express'
import { feathers } from '@feathersjs/feathers'

// Existing Express app
const expressApp = express()
expressApp.get('/health', (req, res) => res.json({ status: 'ok' }))

// Add Feathers to it
const app = feathersExpress(feathers(), expressApp)

app.configure(rest())
app.use('/api/users', userService)

app.listen(3030)

Express Sub-Apps

Feathers works seamlessly with Express sub-apps and routers:

import express, { Router } from '@feathersjs/express'

const app = express(feathers())

// Use Express Router
const apiRouter = Router()
apiRouter.get('/status', (req, res) => res.json({ ok: true }))
app.use('/api', apiRouter)

// Use Express sub-apps
const adminApp = express()
adminApp.get('/dashboard', (req, res) => res.send('Admin'))
app.use('/admin', adminApp)

HTTPS Support

Run Feathers with HTTPS:

import https from 'https'
import fs from 'fs'
import { feathers } from '@feathersjs/feathers'
import express, { rest } from '@feathersjs/express'

const app = express(feathers())
app.configure(rest())

const httpsServer = https.createServer({
  key: fs.readFileSync('privatekey.pem'),
  cert: fs.readFileSync('certificate.pem')
}, app)

await app.setup(httpsServer)
httpsServer.listen(443)

Lifecycle Methods

listen()

The listen() method starts the server and calls setup() on all services:

const server = await app.listen(3030)
console.log('Server started')

setup()

Manually call setup() when using a custom server:

const server = http.createServer(app)
await app.setup(server)
server.listen(3030)

teardown()

Clean shutdown closes the HTTP server and calls teardown on services:

await app.teardown()
console.log('Server stopped')

TypeScript Support

import { feathers, Service } from '@feathersjs/feathers'
import express, { Application } from '@feathersjs/express'

interface User {
  id: number
  email: string
  name: string
}

interface ServiceTypes {
  users: Service<User>
}

interface Configuration {
  host: string
  port: number
}

const app: Application<ServiceTypes, Configuration> = express(feathers())

app.set('host', 'localhost')
app.set('port', 3030)

app.use('/users', {
  async find() {
    return [{ id: 1, email: '[e-mail]', name: 'User' }]
  }
})

const port = app.get('port')
await app.listen(port)

API Reference

express(feathersApp, expressApp?)

Wraps a Feathers application with Express.

Parameters:

• feathersApp - A Feathers application instance
• expressApp - Optional existing Express app

Returns: Combined Feathers + Express application

rest(options?)

Configures the REST transport.

Options:

• formatter - Custom response formatter middleware
• authentication - Authentication settings
  • service - Authentication service name
  • strategies - Array of strategy names

errorHandler(options?)

Express error handling middleware.

Options:

• logger - Logger instance or false to disable
• html - HTML error handlers (function or file paths)
• json - JSON error handlers (function or default)
• public - Path to public error pages directory

notFound(options?)

Handles 404 errors.

Options:

• verbose - Include URL in error message