Coming from Express?

You already know bunWay. Same (req, res, next) signature, same middleware names, same routing patterns. Three things change on the way in:

1Change the importrequire() → import

2Rename the factoryexpress() → bunway()

3Delete npm middleware26 built-ins ship with bunWay — no installs needed

26Built-in middleware

0npm dependencies

~1.6×Faster than Express

The Diff

Here's a real Express app migrated to bunWay. Every unmarked line is untouched.

const express = require('express') 
const cors    = require('cors')    
const helmet  = require('helmet')  
const morgan  = require('morgan')  
import { bunway, cors, helmet, logger, json, session } from 'bunway'

const app = express() 
const app = bunway()  

app.use(cors())
app.use(helmet())
app.use(morgan('dev')) 
app.use(logger('dev')) 
app.use(express.json()) 
app.use(json())         
app.use(session({ secret: 'keyboard cat' }))

app.get('/users/:id', (req, res) => {
  res.json({ id: req.params.id })
})

app.listen(3000)

What's Different

Only two things change

1. ES modules only — use import instead of require(). bunWay is TypeScript-first and ships no CommonJS build.
2. Bun runtime — run with bun server.ts instead of node server.js.

The handler signature (req, res, next), every method, every property — identical.

Middleware Replacements

Delete the npm package and update the import. The API is identical unless noted in the full reference below.

Body Parsing

express.json()→json()

express.urlencoded()→urlencoded()

body-parser.text()→text()

body-parser.raw()→raw()

Security

helmet→helmet()

express-rate-limit→rateLimit()

csurf→csrf()

hpp→hpp()

express-session→session()

cookie-parser→cookieParser()

Files & Assets

express.static()→serveStatic()

multer→upload()

serve-favicon→favicon()

compression→compression()

Observability & Utilities

morgan→logger()

response-time→responseTime()

express-request-id→requestId()

method-override→methodOverride()

connect-timeout→timeout()

cors→cors()

express-validator→validate()

express-sse→sse()

custom 4-arg middleware→errorHandler()

API Reference

The request and response objects are 1:1 with Express. Open any section — identical means zero code changes, enhanced means bunWay is a superset.

Request — properties

Property	Status
req.params	identical
req.query	identical
req.body	identical
req.cookies	identical
req.path	identical
req.method	identical
req.ip	identical
req.session	identical
req.protocol	identical
req.secure	identical

Request — methods

Method	Status	Notes
req.get(header)	identical
req.fresh / req.stale	identical	ETag + Last-Modified cache validation
req.range(size)	identical	Range header parsing
req.param(name)	identical	params → body → query
req.acceptsCharsets()	identical
req.acceptsEncodings()	identical
req.acceptsLanguages()	identical
req.is(type)	enhanced	Supports text/* and application/* wildcards
req.accepts(type)	enhanced	RFC 7231 quality-value parsing

Response — methods

Method	Status	Notes
res.json()	identical
res.send()	enhanced	Auto content-type detection + chainable
res.status()	identical
res.set()	identical
res.cookie()	identical
res.redirect()	identical
res.sendStatus()	identical
res.sendFile()	enhanced	Automatic 206 Partial Content
res.jsonp()	identical
res.download()	enhanced	Optional error callback
res.attachment()	enhanced	Auto content-type detection
res.end()	enhanced	Encoding + callback support

Routing & server

API	Status	Notes
app.get/post/put/delete()	identical
app.use()	identical	Array path mounting supported
app.route(path)	identical	Chainable route definitions
import { Router } from "bunway"	identical	Was express.Router()
Router({ mergeParams: true })	identical
req.res / res.req	identical	Cross-references set during dispatch
res.app	identical
Regex routes	new	app.get(/\/fly$/, handler)
app.all('*', handler)	identical
Sub-app mounting	enhanced	app.mountpath + app.path()
app.listen({ tls: opts })	enhanced	Native TLS — no https.createServer()
app.close(cb)	identical

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