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File Upload & Download Testing

? File Upload & Download Testing

? Quick Overview

Postman allows testing APIs that handle file uploads and downloads. This includes multipart/form-data for uploads and binary file responses for downloads. These tests are essential for validating backend file handling logic.

? Key Concepts

  • Multipart Form Data
  • Binary File Responses
  • Content-Type Headers
  • File Streams
  • API Validation

? Syntax / Theory

File uploads usually use multipart/form-data, while downloads return binary streams with headers like Content-Disposition.

? Code Example(s)

? View Code Example
// Example of multipart file upload request
POST /upload HTTP/1.1
Content-Type: multipart/form-data

file=@document.pdf
? View Code Example
// Example of file download response headers
HTTP/1.1 200 OK
Content-Type: application/pdf
Content-Disposition: attachment; filename="document.pdf"

? Live Output / Explanation

In Postman, uploaded files appear in the request body preview. Downloaded files can be saved locally using the “Save Response” option when binary data is returned.

? Interactive Example / Diagram

You can visually verify file uploads by checking server logs and response sizes. For downloads, inspect response headers and ensure binary mode is enabled.

Body > form-data
Key
Type
Value
file
File ▾
? Click to select document.pdf

? Use Cases

  • User profile image upload
  • Document management systems
  • Report export APIs
  • Media streaming services

? Tips & Best Practices

  • Always validate file size and type on server
  • Use correct Content-Type headers
  • Test with multiple file formats

? Try It Yourself

  • Create an API that accepts image uploads
  • Test file downloads with different MIME types
  • Validate error handling for large files