Supported Languages for Serverless Functions

Within the /api directory of your projects, Vercel will automatically recognize the languages listed on this page, through their file extensions, and serve them as Serverless Function.

Note: In a Next.js application, use /pages/api for Node.js functions and use/api for all other languages.

Node.js

File Extensions: .js, .ts
Default Version: 12.x (or defined)

Node.js files through a JavaScript file or a TypeScript file within the api directory, containing a default exported function, will be served as Serverless Functions.

For example, the following would live in api/hello.js:

module.exports = (req, res) => {
  const { name = 'World' } = req.query
  res.status(200).send(`Hello ${name}!`)
}

An example Node.js function that receives a name query and returns a greeting string.

Example deployment: https://node-api.now-examples.now.sh/api/hello?name=reader

The Serverless Function with the name query parameter using Node.js to change the name.

Using TypeScript

Deploying a Node.js function with the .ts extension will automatically be recognized as a TypeScript file and compiled to a Serverless Function.

As an example; a file called hello.ts in the api directory, and importing types for the Vercel platform Request and Response objects from the @vercel/node module:

import { NowRequest, NowResponse } from '@vercel/node'

export default (request: NowRequest, response: NowResponse) => {
  const { name = 'World' } = request.query
  response.status(200).send(`Hello ${name}!`)
}

An example TypeScript Node.js function that receives a name query and returns a greeting string.

Example deployment: https://ts-api.now-examples.now.sh/api/hello?name=reader

You can install the @vercel/node module for type definitions through npm:

npm i -D @vercel/node

Installing the @vercel/node module for Type definitions of NowRequest and NowResponse

You can also define a tsconfig.json to configure the Vercel TypeScript compiler.

Advanced Node.js Usage

For more advanced usage of Node.js on the Vercel platform, including information about the request and response objects, extended helpers for Node.js on Vercel, private npm packages, or advanced configuration, see the Node.js runtime documentation.

Go

File Extension: .go
Default Version: Go 1.16 (or defined)

Go files in the api directory that export a function matching the net/http Go API will be served as Serverless Functions.

For example, the following would live in api/date.go:

package handler

import (
    "fmt"
    "net/http"
    "time"
)

func Handler(w http.ResponseWriter, r *http.Request) {
    currentTime := time.Now().Format(time.RFC850)
    fmt.Fprintf(w, currentTime)
}

An example Go function that returns the current date.

Note: Your Go function must begin with a capital letter in order to be exported.

When deployed, the example function above will be served as a Serverless Function, returning the latest date. See it live with the following link: https://go-api.now-examples.now.sh/api/date

Advanced Go Usage

For more advanced usage of Go on the Vercel platform, including dependencies, build configuration, private dependencies, or advanced configuration, see the Go runtime documentation.

Python

File Extension: .py
Default Version: Python 3.6

Python files within the api directory, containing an handler variable that inherits from the BaseHTTPRequestHandler class or an app variable that exposes a WSGI or ASGI application, will be served as Serverless Functions.

For example, the following would live in api/date.py:

from http.server import BaseHTTPRequestHandler
from datetime import datetime

class handler(BaseHTTPRequestHandler):

  def do_GET(self):
    self.send_response(200)
    self.send_header('Content-type', 'text/plain')
    self.end_headers()
    self.wfile.write(str(datetime.now().strftime('%Y-%m-%d %H:%M:%S')).encode())
    return

An example Python function that returns the current date.

When deployed, the example function above will be served as a Serverless Function, returning the current date and time. See it live with the following link: https://python-api.now-examples.now.sh/api/date

Advanced Python Usage

For more advanced usage of Python on the Vercel platform, including dependencies, WSGI applications, ASGI applications, or advanced configuration, see the Python runtime documentation.

Ruby

File Extension: .rb
Default Version: Ruby 2.7.x

Ruby files that define a singular HTTP handler, within the api directory, will be served as Serverless Functions.

For example, the following would live in api/date.rb:

Handler = Proc.new do |req, res|
  res.status = 200
  res['Content-Type'] = 'text/text; charset=utf-8'
  res.body = "Current Time: #{Time.new}"
end

An example Ruby function that returns the current date.

When deployed, the example function above will be served as a Serverless Function, returning the current date and time. See it live with the following link: https://ruby-date.now.sh/api/date

Supported Languages for Serverless Functions