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Posted on • Edited on • Originally published at zencoding.hashnode.dev

Crafting a Minimalist File Upload API with Node.js and Express

#node #webdev #backend #backenddevelopment

Crafting a Minimalist File Upload API with Node.js and Express

Need a simple file upload API without the overhead of a full-blown framework? Today, we’ll craft a calm, minimalist solution using Node.js and Express.

Just pure backend bliss.

Table of Contents

Why Keep It Simple?

A basic file upload service is a common sidekick:

  • Upload profile pictures

  • Submit documents

  • Store small attachments

By using only Node.js + Express with a sprinkle of Multer, we can avoid bloat and focus on clarity.

Project Setup

Let’s spin up a fresh project:

mkdir file-upload-api cd file-upload-api npm init -y npm install express multer
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Then create an entry file:

touch index.js
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Building the API

  1. Create the Express Server 
// index.js const express = require('express'); const multer = require('multer'); const path = require('path'); const app = express(); const PORT = 3000; // Set storage engine const storage = multer.diskStorage({ destination: './uploads/', filename: (req, file, cb) => { cb(null, `${Date.now()}-${file.originalname}`); } }); const upload = multer({ storage }); // Middleware app.use(express.json()); // Upload endpoint app.post('/upload', upload.single('file'), (req, res) => { if (!req.file) { return res.status(400).json({ message: 'No file uploaded.' }); } res.status(201).json({ filename: req.file.filename }); }); // Start server app.listen(PORT, () => console.log(`Server running on http://localhost:${PORT}`));
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  1. Create the Express Server

Make sure there’s a folder to store uploaded files:

mkdir uploads
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Testing the Upload

You can test the API using Postman or cURL: Using cURL:

curl -F "file=@/path/to/your/file.jpg" http://localhost:3000/upload
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You should receive:

{ "filename": "timestamp-file.jpg" }
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And the file should appear inside the /uploads directory.

Using Postman:

  • Create a new POST request to http://localhost:3000/upload
  • Under “Body” select “form-data”
  • Add a field named file
  • Attach a file
  • Hit Send!

Next Steps

This calm little project can be expanded:
* Add file type restrictions (only images, only PDFs)
* Limit file size
* Integrate cloud storage (S3, Azure Blob)
* Add simple authentication

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