How do you fetch instagram?

I see some websites that can fetch an instagram profile and get all their posts, reels and videos by simply typing the username and I don't understand how they do it because it's so fast. I've tried scraping instagram's profile by doing this:
const fs = require("fs")
const url = "https://instagram.com/instagram"

async function Scrape() {

const headers = new Headers()

const res = await fetch(url)
const data = await res.text()

fs.writeFile("result.html", data, err => {
if(err) {
console.log(err)
} else {
console.log("file written successfully")
}
})

}

Scrape()
const fs = require("fs")
const url = "https://instagram.com/instagram"

async function Scrape() {

const headers = new Headers()

const res = await fetch(url)
const data = await res.text()

fs.writeFile("result.html", data, err => {
if(err) {
console.log(err)
} else {
console.log("file written successfully")
}
})

}

Scrape()
But in result.html I only get a sorry there's nothing here page. How do they do it? For example go to https://igdownloader.app/ and type https://instagram.com/instagram
IGDownloader.app
Instagram Downloader: Videos, Photos, Story, Reels, IGTV - IGDownlo...
IGDownloader is an Instagram downloader that helps you to download videos, photos, stories, Reels and IGTV from Instagram. Support iPhone, Android.
1 Reply
Jochem
Jochem4mo ago
Meta for Developers
Instagram APIs | Facebook for Developers
Instagram APIs lets you manage and build unique services. Gain tools to help your business interact with the Instagram community.