Rust File Upload with Axum

Handle multipart file uploads in Rust using Axum with size limits, content type validation, streaming to disk, and async file operations using tokio for.

Rust File Upload Updated: 2026-01-15

Code

snippet

use axum::{
  extract::Multipart,
  response::Json,
};
use serde_json::{json, Value};

async fn upload(mut multipart: Multipart) -> Json<Value> {
  while let Some(field) = multipart.next_field().await.unwrap() {
    let name = field.file_name().unwrap_or("unknown").to_string();
    let data = field.bytes().await.unwrap();
    if data.len() > 10 * 1024 * 1024 {
      return Json(json!({"error": "File too large"}));
    }
    tokio::fs::write(format!("uploads/{name}"), data).await.unwrap();
  }
  Json(json!({"status": "ok"}))
}