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POST /api/files/upload

Upload files to Vercel Blob storage. Currently supports image files (JPEG and PNG) up to 5MB.

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Authentication

Requires authenticated session. Returns 401 if not authenticated.

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Request

This endpoint expects a multipart/form-data request with a file field.
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file
File
required
The file to upload. Must be a JPEG or PNG image under 5MB.

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Validation rules

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file size
constraint
Maximum 5MB (5,242,880 bytes)
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file type
constraint
Must be image/jpeg or image/png

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Response

Returns a blob metadata object on success.
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url
string
Public URL of the uploaded file
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pathname
string
Path of the file in blob storage
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contentType
string
MIME type of the uploaded file
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contentDisposition
string
Content disposition header value

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Example

const formData = new FormData();
formData.append("file", file);

const response = await fetch("/api/files/upload", {
  method: "POST",
  body: formData,
});

const data = await response.json();
console.log(data.url); // https://blob-url.vercel-storage.com/filename.png

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Error responses

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400 Bad Request
error
  • No file uploaded
  • File size exceeds 5MB
  • File type is not JPEG or PNG
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401 Unauthorized
error
User is not authenticated
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500 Internal Server Error
error
  • Upload to Vercel Blob failed
  • Failed to process request

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Implementation

The endpoint uses Vercel Blob’s put function with public access. Files are stored with their original filename.
app/(chat)/api/files/upload/route.ts
import { put } from "@vercel/blob";

const data = await put(`${filename}`, fileBuffer, {
  access: "public",
});
To support additional file types, update the FileSchema validation in the route handler.

Chat interface

Learn how files are used in chat messages

Data persistence

Learn about Vercel Blob storage configuration

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