Every backend app needs to answer a boring question:

“Where do we put all these images and videos?”

You’ve got options: object storage (like AWS S3), or dedicated media platforms like Cloudinary.

Let’s zoom in on Cloudinary, because it solves more than just “where to store the file”.

Cloudinary is a cloud media platform for:
- Uploading & secure storage
- On-the-fly transformations/optimization
- Fast delivery via CDN

Teams use it so they don’t reinvent: thumbnails, formats, compression, secure URLs, etc.

Config (Node.js SDK):
You configure Cloudinary with three values from your Cloudinary console after creating a project:
- cloud_name
- api_key
- api_secret

before anything you must install cloudinary package
npm i cloudinary

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import { v2 as cloudinary } from 'cloudinary';
cloudinary.config({
cloud_name: process.env.CLOUDINARY_CLOUD_NAME,
api_key: process.env.CLOUDINARY_API_KEY,
api_secret: process.env.CLOUDINARY_API_SECRET,
});

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Best practice: put them in env vars (e.g. CLOUDINARY_URL or separate CLOUDINARY_CLOUD_NAME / API_KEY / API_SECRET). Never expose api_secret to the frontend.

Upload flow (server-side with streams):
In a typical Node backend, the client sends a multipart request, you parse it into a readable stream, then stream directly to Cloudinary.

upload_stream is the key here.
- It creates a writable stream that accepts file data
- Perfect when you don’t want to write temp files to disk

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import { v2 as cloudinary } from "cloudinary";
import { Readable } from "stream";

function uploadBuffer(buffer: Buffer): Promise<any> {
return new Promise((resolve, reject) => {
   const stream = cloudinary.uploader.upload_stream(
    { folder: "users" },
    (error, result) => {
    if (error) return reject(error);
     resolve(result);
    });

Readable.from(buffer).pipe(stream);
});
}

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result from cloudinary:
{
"asset_id":"...",
"public_id":"users/profile_123",
"secure_url":"https://lnkd.in/e2EDRN4A..."
}

secure_url -> represents image url

public_id represents the asset’s identifier in Cloudinary. Store it in your DB so you can later:
- Delete the asset
- Overwrite/update it
- Generate transformation/delivery URLs
- Fetch metadata

Crucial detail: with upload_stream, nothing is uploaded until you actually write/end the stream.

That “last line” where you pipe the incoming readable stream into Cloudinary?
That’s when the upload really starts.

pipe() wires things up:
Readable (from request / multipart parser) -> Writable (Cloudinary upload_stream).

Result: data goes straight from the client to Cloudinary, without ever touching your server’s disk.

How are you handling uploads today in your backend?

Store Images in Your Node.js Backend with Cloudinary (No Temporary Files)