Defaults for Fastify that everyone can agree on

Usage no npm install needed!

<script type="module">
  import fastifySensible from '';



CI NPM version Known Vulnerabilities js-standard-style

Defaults for Fastify that everyone can agree on™.
This plugin adds some useful utilities to your Fastify instance, see the API section to learn more.

Supports Fastify versions 3.x. Please refer to this branch and related versions for Fastify 2.x compatibility. Please refer to this branch and related versions for Fastify 1.x compatibility.

Why are these APIs here and not included with Fastify?
Because Fastify aims to be as small and focused as possible, every utility that is not essential should be shipped as standalone plugin.


npm i fastify-sensible


const fastify = require('fastify')()

fastify.get('/', (req, reply) => {

fastify.get('/async', async (req, reply) => {
  throw fastify.httpErrors.notFound()




Object that exposes createError and all the 4xx and 5xx error constructors.

Usage of 4xx and 5xx error constructors follows the same structure as new createError[code || name]([msg])) in http-errors:

 // the custom message is optional
const notFoundErr = fastify.httpErrors.notFound('custom message')


  • fastify.httpErrors.badRequest()
  • fastify.httpErrors.unauthorized()
  • fastify.httpErrors.paymentRequired()
  • fastify.httpErrors.forbidden()
  • fastify.httpErrors.notFound()
  • fastify.httpErrors.methodNotAllowed()
  • fastify.httpErrors.notAcceptable()
  • fastify.httpErrors.proxyAuthenticationRequired()
  • fastify.httpErrors.requestTimeout()
  • fastify.httpErrors.conflict()
  • fastify.httpErrors.gone()
  • fastify.httpErrors.lengthRequired()
  • fastify.httpErrors.preconditionFailed()
  • fastify.httpErrors.payloadTooLarge()
  • fastify.httpErrors.uriTooLong()
  • fastify.httpErrors.unsupportedMediaType()
  • fastify.httpErrors.rangeNotSatisfiable()
  • fastify.httpErrors.expectationFailed()
  • fastify.httpErrors.imateapot()
  • fastify.httpErrors.misdirectedRequest()
  • fastify.httpErrors.unprocessableEntity()
  • fastify.httpErrors.locked()
  • fastify.httpErrors.failedDependency()
  • fastify.httpErrors.unorderedCollection()
  • fastify.httpErrors.upgradeRequired()
  • fastify.httpErrors.preconditionRequired()
  • fastify.httpErrors.tooManyRequests()
  • fastify.httpErrors.requestHeaderFieldsTooLarge()
  • fastify.httpErrors.unavailableForLegalReasons()


  • fastify.httpErrors.internalServerError()
  • fastify.httpErrors.notImplemented()
  • fastify.httpErrors.badGateway()
  • fastify.httpErrors.serviceUnavailable()
  • fastify.httpErrors.gatewayTimeout()
  • fastify.httpErrors.httpVersionNotSupported()
  • fastify.httpErrors.variantAlsoNegotiates()
  • fastify.httpErrors.insufficientStorage()
  • fastify.httpErrors.loopDetected()
  • fastify.httpErrors.bandwidthLimitExceeded()
  • fastify.httpErrors.notExtended()
  • fastify.httpErrors.networkAuthenticationRequired()


Usage of createError follows the same structure as createError([status], [message], [properties]) in http-errors:

var err = fastify.httpErrors.createError(404, 'This video does not exist!')


The reply interface is decorated with all the functions declared above, using it is very easy:

fastify.get('/', (req, reply) => {


The reply interface is decorated with jshttp/vary, the API is the same, but you do not need to pass the res object.

fastify.get('/', (req, reply) => {


The request interface is decorated with jshttp/forwarded, the API is the same, but you do not need to pass the request object:

fastify.get('/', (req, reply) => {

The request interface is decorated with jshttp/type-is, the API is the same, but you do not need to pass the request object:

fastify.get('/', (req, reply) => {
  reply.send(['html', 'json']))


Verify if a given condition is true, if not it throws the specified http error.
Very useful if you work with async routes:

// the custom message is optional
  req.headers.authorization, 400, 'Missing authorization header'

The assert API exposes also the following methods:

  • fastify.assert.ok()
  • fastify.assert.equal()
  • fastify.assert.notEqual()
  • fastify.assert.strictEqual()
  • fastify.assert.notStrictEqual()
  • fastify.assert.deepEqual()
  • fastify.assert.notDeepEqual()


Async await wrapper for easy error handling without try-catch, inspired by await-to-js:

const [err, user] = await
  db.findOne({ user: 'tyrion' })

Custom error handler

This plugins also adds a custom error handler, which hides the error message in case of 500 errors that are being generated by throwed errors, instead it returns Something went wrong.
This is especially useful if you are using async routes, where every uncaught error will be sent back to the user (but do not worry, the original error message is logged as error in any case). If needed, it can be disabled by setting the option errorHandler to false.

If you return a 500 error via the API provided on fastify.httpErrors and reply objects, the custom error message is preserved and returned in the HTTP response body.


Do you feel there is some utility that everyone can agree on which is not present?
Open an issue and let's discuss it! Even better a pull request!


The project name is inspired by vim-sensible, an awesome package that if you use vim you should use too.


MIT Copyright © 2018 Tomas Della Vedova