Blazor.DownloadFileFast

June 13, 2025 · View on GitHub

Fast download from files to the browser from Blazor without any javascript library reference or dependency.

BlazorDownloadFileFast is the solution to saving files on the client-side, and is perfect for web apps that generates files on the client.

When using this project in a NET 5 (and up) Blazor WebAssembly project, there is an additional speed increase. Read the blog post mentioned from Gérald Barré in the credits.

Usage

Register

builder.Services.AddBlazorDownloadFile();

Inject in code-behind

[Inject]
public IBlazorDownloadFileService BlazorDownloadFileService { get; set; }

Use in your code

byte[] bytes = ...; 
await BlazorDownloadFileService.DownloadFileAsync("example.txt", bytes);

Credits

The idea and code from this project is based on Generating and efficiently exporting a file in a Blazor WebAssembly application
For resolving the Content-Type based on the file extension, this code is used: MimeTypeMap
This project is inspired by BlazorDownloadFile