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Build Your First API with Node.js: A Step-by-Step Guide

Build Your First API with Node.js: A Step-by-Step Guide

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Subham
·

15 min read

Table of contents

Hi, I'm Subham Maity, a software engineer. I also enjoy teaching others how to code through my tutorials. I'm always eager to learn new things and share my knowledge with the community.

⚡ I recently wrote an article on Build Your First API and wanted to share it with you all. You can find the article on my website https://codexam.vercel.app/docs/node/node1 [Better View]

⚡ I also have a repository on GitHub where you can find all the code and projects related to this topic. You can find the repository at https://github.com/Subham-Maity/node-js-full-stack-tutorial

❗ For a more in-depth look at this topic, including a detailed table of contents, check out the complete tutorial on my GitHub Repo

If you want to stay updated with my latest projects and articles, you can follow me on:

  1. We already know how to make a simple server. You can check it out the previous chapter
const http = require('http');

http.createServer((req, res) => {



  }
).listen(5000);
  1. Now res.writeHead(200, {'Content-Type': 'application/json'}); - This line sets the response status code and headers using the writeHead method of the res (response) object
  • writeHead method takes two arguments, the first is the status code and the second is an object containing the response headers (in this case, we are setting the Content-Type header to application/json)
  • The writeHead method is used to send the response status code and headers to the client
  • The status code 200 is a standard HTTP status code that indicates the request was successful.
  • The Content-Type header is used to specify the media type of the resource being sent in the response body this means that the client can expect to receive data in a specific format.
  • application/json, indicating that the response body will contain data in JSON format & we use / to separate the type and subtype of the media type.
  1. Now res.write(JSON.stringify({name: 'Subham', age: 20})); - This line writes the response body using the write method of the res (response) object
  • The write method is used to send the response body to the client means that the client can expect to receive data in a specific format.
  • The JSON.stringify method is used to convert a JavaScript object to a JSON string
  • In this case, it is sending a JSON representation of an object with properties name and age.
  • The JSON.stringify method takes a single argument, the object to be converted to a JSON string
  1. Now res.end(); - This line signals the end of the response and sends it to the client using the end method of the res (response) object.
  • The end method is used to indicate that all of the response headers and body have been sent and that the server should consider this message complete.

These lines of code are part of a Node.js server that sends a response to an HTTP request. The writeHead method is used to set the response status code and headers. In this case, the status code is set to 200 to indicate success, and the Content-Type header is set to application/json to indicate that the response will contain JSON data. The write method is used to send data in the response body. In this case, it sends a JSON representation of an object with properties name and age. Finally, the end method is used to signal the end of the response and send it to the client.

const http = require('http');

http.createServer((req, res) => {

   res.writeHead(200, {'Content-Type': 'application/json'});
   res.write(JSON.stringify({name: 'Subham', age: 20}));
   res.end();
  }
).listen(5000);

  1. Now we can run this server using nodemon server.js and check it out in the browser using localhost:5000

  2. Now we can see the output in the browser like this

{
  "name": "Subham",
  "age": 20
}

You can also check it out in the postman we already discussed about it in this project section here

📝 Separate the data using data.js

  1. Create a new file data.js and add this code
const data ={
    "name":"Rajesh",
    "age": 20,
    "email": "rajesh@dev.com"
}
module.exports=data;

  • Here const data is a variable which contains an object with some data

    • name is a property of the object and its value is Rajesh

    • age is a property of the object and its value is 20

    • email is a property of the object and its value is `

  • module.exports=data is used to export the data variable so that it can be used in other files

  1. Now we can import this data in the server.js file using require method
const data = require('./data');
  1. Now pass the data variable in the write method of the res object inside JSON.stringify method like this
res.write(JSON.stringify(data));

  1. Now we can run this server using nodemon server.js and check it out in the browser using localhost:5000

  2. Now we can see the output in the browser like this

{"name":"Rajesh","age":20,"email":"rajesh@dev.com"}

📝 Add more data in the data.js file

  1. Now we can add more data in the data.js file like this

const data = [
  {
    name: "Rajesh",
    age: 20,
    address: {
      city: "Delhi",
      state: "Delhi",
      country: "India",
    },
    hobbies: ["coding", "reading", "playing"],
    skills: ["html", "css", "js", "nodejs"],
    education: {
      school: "Delhi Public School",
      college: "Delhi University",
      degree: "B.Tech",
    },
    projects: {
      project1: "Portfolio",
      project2: "Blog",
      project3: "E-commerce",
    },
    social: {
      github: "rajesh.github.io",
      linkedin: "rajesh.linkedin.com",
      twitter: "rajesh.twitter.com",
    },
    work: {
      company: "XYZ",
      position: "Software Engineer",
      experience: "2 years",
    },
    achievements: {
      achievement1: "Won a hackathon",
      achievement2: "Got a scholarship",
      achievement3: "Got a job",
    },
    interests: {
      interest1: "Reading",
      interest2: "Playing",
      interest3: "Coding",
    },
    languages: {
      language1: "English",
      language2: "Hindi",
      language3: "Punjabi",
    },
    contact: {
      phone: "1234567890",
      email: "rajesh.dev.com",
    },
  },
  {
    name: "Subham",
    age: 20,
    address: {
      city: "Delhi",
      state: "Delhi",
      country: "India",
    },
    hobbies: ["coding", "reading", "playing"],
    skills: ["html", "css", "js", "nodejs"],
    education: {
      school: "Delhi Public School",
      college: "Delhi University",
      degree: "B.Tech",
    },
    projects: {
      project1: "Portfolio",
      project2: "Blog",
      project3: "E-commerce",
    },
    social: {
      github: "subham.github.io",
      linkedin: "subham.linkedin.com",
      twitter: "subham.twitter.com",
    },
    work: {
      company: "XYZ",
      position: "Software Engineer",
      experience: "2 years",
    },
    achievements: {
      achievement1: "Won a hackathon",
      achievement2: "Got a scholarship",
      achievement3: "Got a job",
    },
    interests: {
      interest1: "Reading",
      interest2: "Playing",
      interest3: "Coding",
    },
    languages: {
      language1: "English",
      language2: "Hindi",
      language3: "Punjabi",
    },
    contact: {
      phone: "1234567890",
      email: "subham.dev.com",
    },
  },
  {
    name: "Rahul",
    age: 20,
    address: {
      city: "Delhi",
      state: "Delhi",
      country: "India",
    },
    hobbies: ["coding", "reading", "playing"],
    skills: ["html", "css", "js", "nodejs"],
    education: {
      school: "Delhi Public School",
      college: "Delhi University",
      degree: "B.Tech",
    },
    projects: {
      project1: "Portfolio",
      project2: "Blog",
      project3: "E-commerce",
    },
    social: {
      github: "rahul.github.io",
      linkedin: "rahul.linkedin.com",
      twitter: "rahul.twitter.com",
    },
    work: {
      company: "XYZ",
      position: "Software Engineer",
      experience: "2 years",
    },
    achievements: {
      achievement1: "Won a hackathon",
      achievement2: "Got a scholarship",
      achievement3: "Got a job",
    },
    interests: {
      interest1: "Reading",
      interest2: "Playing",
      interest3: "Coding",
    },
    languages: {
      language1: "English",
      language2: "Hindi",
      language3: "Punjabi",
    },
    contact: {
      phone: "1234567890",
      email: "rahul.dev.com",
    },
  },
];

module.exports = data;
  1. Now our server will look like this

const http = require('http');
const data = require('./data');

http.createServer((req, res) => {

   res.writeHead(200, {'Content-Type': 'application/json'});
   res.write(JSON.stringify(data));
   res.end();
  }
).listen(5000);

  1. Now we can run this server using nodemon server.js and check it out in the browser using localhost:5000

  2. Now we can see the output in the browser like this

[{"name":"Rajesh","age":20,"address":{"city":"Delhi","state":"Delhi","country":"India"},"hobbies":["coding","reading","playing"],"skills":["html","css","js","nodejs"],"education":{"school":"Delhi Public School","college":"Delhi University","degree":"B.Tech"},"projects":{"project1":"Portfolio","project2":"Blog","project3":"E-commerce"},"social":{"github":"rajesh.github.io","linkedin":"rajesh.linkedin.com","twitter":"rajesh.twitter.com"},"work":{"company":"XYZ","position":"Software Engineer","experience":"2 years"},"achievements":{"achievement1":"Won a hackathon","achievement2":"Got a scholarship","achievement3":"Got a job"},"interests":{"interest1":"Reading","interest2":"Playing","interest3":"Coding"},"languages":{"language1":"English","language2":"Hindi","language3":"Punjabi"},"contact":{"phone":"1234567890","email":"rajesh.dev.com"}},{"name":"Subham","age":20,"address":{"city":"Delhi","state":"Delhi","country":"India"},"hobbies":["coding","reading","playing"],"skills":["html","css","js","nodejs"],"education":{"school":"Delhi Public School","college":"Delhi University","degree":"B.Tech"},"projects":{"project1":"Portfolio","project2":"Blog","project3":"E-commerce"},"social":{"github":"subham.github.io","linkedin":"subham.linkedin.com","twitter":"subham.twitter.com"},"work":{"company":"XYZ","position":"Software Engineer","experience":"2 years"},"achievements":{"achievement1":"Won a hackathon","achievement2":"Got a scholarship","achievement3":"Got a job"},"interests":{"interest1":"Reading","interest2":"Playing","interest3":"Coding"},"languages":{"language1":"English","language2":"Hindi","language3":"Punjabi"},"contact":{"phone":"1234567890","email":"subham.dev.com"}},{"name":"Rahul","age":20,"address":{"city":"Delhi","state":"Delhi","country":"India"},"hobbies":["coding","reading","playing"],"skills":["html","css","js","nodejs"],"education":{"school":"Delhi Public School","college":"Delhi University","degree":"B.Tech"},"projects":{"project1":"Portfolio","project2":"Blog","project3":"E-commerce"},"social":{"github":"rahul.github.io","linkedin":"rahul.linkedin.com","twitter":"rahul.twitter.com"},"work":{"company":"XYZ","position":"Software Engineer","experience":"2 years"},"achievements":{"achievement1":"Won a hackathon","achievement2":"Got a scholarship","achievement3":"Got a job"},"interests":{"interest1":"Reading","interest2":"Playing","interest3":"Coding"},"languages":{"language1":"English","language2":"Hindi","language3":"Punjabi"},"contact":{"phone":"1234567890","email":"rahul.dev.com"}}]

Status Code

If I send instead of 200, I send 404, it will show not found in the postman status code because there are lots of status codes are there. We use them according to our need.

Some of the status codes are:

  • 200 - OK

  • 201 - Created

  • 204 - No Content

  • 400 - Bad Request

  • 401 - Unauthorized

  • 403 - Forbidden

  • 404 - Not Found

  • 500 - Internal Server Error

  • 503 - Service Unavailable

You can check all the status codes hereHi, I'm Subham Maity, a software engineer. I also enjoy teaching others how to code through my tutorials. I'm always eager to learn new things and share my knowledge with the community.

⚡ I recently wrote an article on Build Your First API and wanted to share it with you all. You can find the article on my website https://codexam.vercel.app/docs/node/node1 [Better View]

⚡ I also have a repository on GitHub where you can find all the code and projects related to this topic. You can find the repository at https://github.com/Subham-Maity/node-js-full-stack-tutorial

❗ For a more in-depth look at this topic, including a detailed table of contents, check out the complete tutorial on my GitHub Repo

If you want to stay updated with my latest projects and articles, you can follow me on:

  1. We already know how to make a simple server. You can check it out the previous chapter
const http = require('http');

http.createServer((req, res) => {



  }
).listen(5000);
  1. Now res.writeHead(200, {'Content-Type': 'application/json'}); - This line sets the response status code and headers using the writeHead method of the res (response) object
  • writeHead method takes two arguments, the first is the status code and the second is an object containing the response headers (in this case, we are setting the Content-Type header to application/json)
  • The writeHead method is used to send the response status code and headers to the client
  • The status code 200 is a standard HTTP status code that indicates the request was successful.
  • The Content-Type header is used to specify the media type of the resource being sent in the response body this means that the client can expect to receive data in a specific format.
  • application/json, indicating that the response body will contain data in JSON format & we use / to separate the type and subtype of the media type.
  1. Now res.write(JSON.stringify({name: 'Subham', age: 20})); - This line writes the response body using the write method of the res (response) object
  • The write method is used to send the response body to the client means that the client can expect to receive data in a specific format.
  • The JSON.stringify method is used to convert a JavaScript object to a JSON string
  • In this case, it is sending a JSON representation of an object with properties name and age.
  • The JSON.stringify method takes a single argument, the object to be converted to a JSON string
  1. Now res.end(); - This line signals the end of the response and sends it to the client using the end method of the res (response) object.
  • The end method is used to indicate that all of the response headers and body have been sent and that the server should consider this message complete.

These lines of code are part of a Node.js server that sends a response to an HTTP request. The writeHead method is used to set the response status code and headers. In this case, the status code is set to 200 to indicate success, and the Content-Type header is set to application/json to indicate that the response will contain JSON data. The write method is used to send data in the response body. In this case, it sends a JSON representation of an object with properties name and age. Finally, the end method is used to signal the end of the response and send it to the client.

const http = require('http');

http.createServer((req, res) => {

   res.writeHead(200, {'Content-Type': 'application/json'});
   res.write(JSON.stringify({name: 'Subham', age: 20}));
   res.end();
  }
).listen(5000);

  1. Now we can run this server using nodemon server.js and check it out in the browser using localhost:5000

  2. Now we can see the output in the browser like this

{
  "name": "Subham",
  "age": 20
}

You can also check it out in the postman we already discussed about it in this project section here

📝 Separate the data using data.js

  1. Create a new file data.js and add this code
const data ={
    "name":"Rajesh",
    "age": 20,
    "email": "rajesh@dev.com"
}
module.exports=data;

  • Here const data is a variable which contains an object with some data

    • name is a property of the object and its value is Rajesh

    • age is a property of the object and its value is 20

    • email is a property of the object and its value is `

  • module.exports=data is used to export the data variable so that it can be used in other files

  1. Now we can import this data in the server.js file using require method
const data = require('./data');
  1. Now pass the data variable in the write method of the res object inside JSON.stringify method like this
res.write(JSON.stringify(data));

  1. Now we can run this server using nodemon server.js and check it out in the browser using localhost:5000

  2. Now we can see the output in the browser like this

{"name":"Rajesh","age":20,"email":"rajesh@dev.com"}

📝 Add more data in the data.js file

  1. Now we can add more data in the data.js file like this

const data = [
  {
    name: "Rajesh",
    age: 20,
    address: {
      city: "Delhi",
      state: "Delhi",
      country: "India",
    },
    hobbies: ["coding", "reading", "playing"],
    skills: ["html", "css", "js", "nodejs"],
    education: {
      school: "Delhi Public School",
      college: "Delhi University",
      degree: "B.Tech",
    },
    projects: {
      project1: "Portfolio",
      project2: "Blog",
      project3: "E-commerce",
    },
    social: {
      github: "rajesh.github.io",
      linkedin: "rajesh.linkedin.com",
      twitter: "rajesh.twitter.com",
    },
    work: {
      company: "XYZ",
      position: "Software Engineer",
      experience: "2 years",
    },
    achievements: {
      achievement1: "Won a hackathon",
      achievement2: "Got a scholarship",
      achievement3: "Got a job",
    },
    interests: {
      interest1: "Reading",
      interest2: "Playing",
      interest3: "Coding",
    },
    languages: {
      language1: "English",
      language2: "Hindi",
      language3: "Punjabi",
    },
    contact: {
      phone: "1234567890",
      email: "rajesh.dev.com",
    },
  },
  {
    name: "Subham",
    age: 20,
    address: {
      city: "Delhi",
      state: "Delhi",
      country: "India",
    },
    hobbies: ["coding", "reading", "playing"],
    skills: ["html", "css", "js", "nodejs"],
    education: {
      school: "Delhi Public School",
      college: "Delhi University",
      degree: "B.Tech",
    },
    projects: {
      project1: "Portfolio",
      project2: "Blog",
      project3: "E-commerce",
    },
    social: {
      github: "subham.github.io",
      linkedin: "subham.linkedin.com",
      twitter: "subham.twitter.com",
    },
    work: {
      company: "XYZ",
      position: "Software Engineer",
      experience: "2 years",
    },
    achievements: {
      achievement1: "Won a hackathon",
      achievement2: "Got a scholarship",
      achievement3: "Got a job",
    },
    interests: {
      interest1: "Reading",
      interest2: "Playing",
      interest3: "Coding",
    },
    languages: {
      language1: "English",
      language2: "Hindi",
      language3: "Punjabi",
    },
    contact: {
      phone: "1234567890",
      email: "subham.dev.com",
    },
  },
  {
    name: "Rahul",
    age: 20,
    address: {
      city: "Delhi",
      state: "Delhi",
      country: "India",
    },
    hobbies: ["coding", "reading", "playing"],
    skills: ["html", "css", "js", "nodejs"],
    education: {
      school: "Delhi Public School",
      college: "Delhi University",
      degree: "B.Tech",
    },
    projects: {
      project1: "Portfolio",
      project2: "Blog",
      project3: "E-commerce",
    },
    social: {
      github: "rahul.github.io",
      linkedin: "rahul.linkedin.com",
      twitter: "rahul.twitter.com",
    },
    work: {
      company: "XYZ",
      position: "Software Engineer",
      experience: "2 years",
    },
    achievements: {
      achievement1: "Won a hackathon",
      achievement2: "Got a scholarship",
      achievement3: "Got a job",
    },
    interests: {
      interest1: "Reading",
      interest2: "Playing",
      interest3: "Coding",
    },
    languages: {
      language1: "English",
      language2: "Hindi",
      language3: "Punjabi",
    },
    contact: {
      phone: "1234567890",
      email: "rahul.dev.com",
    },
  },
];

module.exports = data;
  1. Now our server will look like this

const http = require('http');
const data = require('./data');

http.createServer((req, res) => {

   res.writeHead(200, {'Content-Type': 'application/json'});
   res.write(JSON.stringify(data));
   res.end();
  }
).listen(5000);

  1. Now we can run this server using nodemon server.js and check it out in the browser using localhost:5000

  2. Now we can see the output in the browser like this

[{"name":"Rajesh","age":20,"address":{"city":"Delhi","state":"Delhi","country":"India"},"hobbies":["coding","reading","playing"],"skills":["html","css","js","nodejs"],"education":{"school":"Delhi Public School","college":"Delhi University","degree":"B.Tech"},"projects":{"project1":"Portfolio","project2":"Blog","project3":"E-commerce"},"social":{"github":"rajesh.github.io","linkedin":"rajesh.linkedin.com","twitter":"rajesh.twitter.com"},"work":{"company":"XYZ","position":"Software Engineer","experience":"2 years"},"achievements":{"achievement1":"Won a hackathon","achievement2":"Got a scholarship","achievement3":"Got a job"},"interests":{"interest1":"Reading","interest2":"Playing","interest3":"Coding"},"languages":{"language1":"English","language2":"Hindi","language3":"Punjabi"},"contact":{"phone":"1234567890","email":"rajesh.dev.com"}},{"name":"Subham","age":20,"address":{"city":"Delhi","state":"Delhi","country":"India"},"hobbies":["coding","reading","playing"],"skills":["html","css","js","nodejs"],"education":{"school":"Delhi Public School","college":"Delhi University","degree":"B.Tech"},"projects":{"project1":"Portfolio","project2":"Blog","project3":"E-commerce"},"social":{"github":"subham.github.io","linkedin":"subham.linkedin.com","twitter":"subham.twitter.com"},"work":{"company":"XYZ","position":"Software Engineer","experience":"2 years"},"achievements":{"achievement1":"Won a hackathon","achievement2":"Got a scholarship","achievement3":"Got a job"},"interests":{"interest1":"Reading","interest2":"Playing","interest3":"Coding"},"languages":{"language1":"English","language2":"Hindi","language3":"Punjabi"},"contact":{"phone":"1234567890","email":"subham.dev.com"}},{"name":"Rahul","age":20,"address":{"city":"Delhi","state":"Delhi","country":"India"},"hobbies":["coding","reading","playing"],"skills":["html","css","js","nodejs"],"education":{"school":"Delhi Public School","college":"Delhi University","degree":"B.Tech"},"projects":{"project1":"Portfolio","project2":"Blog","project3":"E-commerce"},"social":{"github":"rahul.github.io","linkedin":"rahul.linkedin.com","twitter":"rahul.twitter.com"},"work":{"company":"XYZ","position":"Software Engineer","experience":"2 years"},"achievements":{"achievement1":"Won a hackathon","achievement2":"Got a scholarship","achievement3":"Got a job"},"interests":{"interest1":"Reading","interest2":"Playing","interest3":"Coding"},"languages":{"language1":"English","language2":"Hindi","language3":"Punjabi"},"contact":{"phone":"1234567890","email":"rahul.dev.com"}}]

Status Code

If I send instead of 200, I send 404, it will show not found in the postman status code because there are lots of status codes are there. We use them according to our need.

Some of the status codes are:

  • 200 - OK

  • 201 - Created

  • 204 - No Content

  • 400 - Bad Request

  • 401 - Unauthorized

  • 403 - Forbidden

  • 404 - Not Found

  • 500 - Internal Server Error

  • 503 - Service Unavailable

You can check all the status codes here

Node.jsAPIsJavaScriptjsWeb Development