Tutorial
6 min read

Server Uploads with Vercel Blob

Learn how to upload files to Vercel Blob using Server Actions and Route Handlers
Table of Contents

Vercel Blob is available in Beta on Hobby and Pro plans

Those with the owner, member, developer role can access this feature

In this quickstart, you'll learn how to do the following:

  • Use the Vercel dashboard to create a Blob store connected to a project
  • Upload a file using the Blob SDK from the server

Vercel has a 4.5 MB request body size limit on Vercel Functions. If you need to upload larger files, use client uploads.

Vercel Blob works with any frontend framework. First, install the package:

pnpm
yarn
npm
pnpm i @vercel/blob
  1. Navigate to the Project you'd like to add the blob store to. Select the Storage tab, then select the Connect Database button.

    Under the Create New tab, select Blob and then the Continue button.

    Use the name "Images" and select Create a new Blob store. Select the environments where you would like the read-write token to be included. You can also update the prefix of the Environment Variable in Advanced Options

    Once created, you are taken to the Vercel Blob store page.

  2. Since you created the Blob store in a project, we automatically created and added the following Environment Variable to the project for you.

    • BLOB_READ_WRITE_TOKEN

    To use this Environment Variable locally, we recommend pulling it with the Vercel CLI:

    vercel env pull .env.development.local

Server uploads are perfectly fine as long as you do not need to upload files larger than 4.5 MB on Vercel. If you need to upload larger files, consider using client uploads.

The following example shows how to use a Server Action with Next.js App Router to upload a file to Vercel Blob.

app/components/form.tsx
import { put } from '@vercel/blob';
import { revalidatePath } from 'next/cache';
 
export async function Form() {
  async function uploadImage(formData: FormData) {
    'use server';
    const imageFile = formData.get('image') as File;
    const blob = await put(imageFile.name, imageFile, {
      access: 'public',
    });
    revalidatePath('/');
    return blob;
  }
 
  return (
    <form action={uploadImage}>
      <label htmlFor="image">Image</label>
      <input type="file" id="image" name="image" required />
      <button>Upload</button>
    </form>
  );
}

Then, add the hostname to your next.config.js file including the store id from the dashboard:

next.config.js
/** @type {import('next').NextConfig} */
const nextConfig = {
  images: {
    remotePatterns: [
      {
        protocol: 'https',
        hostname: 'my-blob-store.public.blob.vercel-storage.com',
        port: '',
      },
    ],
  },
};
 
module.exports = nextConfig;

This will allow you to use next/image to display images from your Vercel Blob store.

app/components/images.tsx
import { list } from '@vercel/blob';
import Image from 'next/image';
 
export async function Images() {
  async function allImages() {
    const blobs = await list();
    return blobs;
  }
  const images = await allImages();
 
  return (
    <section>
      {images.blobs.map((image) => (
        <Image
          priority
          key={image.pathname}
          src={image.url}
          alt="Image"
          width={200}
          height={200}
        />
      ))}
    </section>
  );
}

Read more about Server Actions and App Router on the Next.js documentation.

You can upload files to Vercel Blob using Route Handlers/API Routes. The following example shows how to upload a file to Vercel Blob using a server upload page and route.

  1. This page will upload files to your server. The files will then be sent to Vercel Blob.

    Next.js (/app)
    Next.js (/pages)
    src/app/avatar/upload/page.tsx
    'use client';
     
    import type { PutBlobResult } from '@vercel/blob';
    import { useState, useRef } from 'react';
     
    export default function AvatarUploadPage() {
      const inputFileRef = useRef<HTMLInputElement>(null);
      const [blob, setBlob] = useState<PutBlobResult | null>(null);
      return (
        <>
          <h1>Upload Your Avatar</h1>
     
          <form
            onSubmit={async (event) => {
              event.preventDefault();
     
              if (!inputFileRef.current?.files) {
                throw new Error('No file selected');
              }
     
              const file = inputFileRef.current.files[0];
     
              const response = await fetch(
                `/api/avatar/upload?filename=${file.name}`,
                {
                  method: 'POST',
                  body: file,
                },
              );
     
              const newBlob = (await response.json()) as PutBlobResult;
     
              setBlob(newBlob);
            }}
          >
            <input name="file" ref={inputFileRef} type="file" required />
            <button type="submit">Upload</button>
          </form>
          {blob && (
            <div>
              Blob url: <a href={blob.url}>{blob.url}</a>
            </div>
          )}
        </>
      );
    }
  2. This route forwards the file to Vercel Blob and returns the URL of the uploaded file to the browser.

    Next.js (/app)
    Next.js (/pages)
    src/app/api/avatar/upload/route.ts
    import { put } from '@vercel/blob';
    import { NextResponse } from 'next/server';
     
    export async function POST(request: Request): Promise<NextResponse> {
      const { searchParams } = new URL(request.url);
      const filename = searchParams.get('filename');
     
      const blob = await put(filename, request.body, {
        access: 'public',
      });
     
      return NextResponse.json(blob);
    }
  1. Run your application locally and visit /avatar/upload to upload the file to your store. The browser will display the unique URL created for the file.

    When your local website is served on http://localhost:3000, then the onUploadCompleted step won't succeed as Vercel Blob cannot contact your localhost. Instead, we recommend you run your local application through a tunneling service like ngrok, so you can experience the full Vercel Blob development flow locally.

    • Go to the Vercel Project where you created the store
    • Select the Storage tab and select your new store
    • Paste the blob object URL returned in the previous step in the Blob URL input box in the Browser section and select Lookup
    • The following blob object metadata will be displayed: file name, path, size, uploaded date, content type and HTTP headers
    • You also have the option to download and delete the file from this page

You have successfully uploaded an object to your Vercel Blob store and are able to review it's metadata, download, and delete it from your Vercel Storage Dashboard.

Last updated on June 20, 2024