Simplifying QR Code Generation for 2FA in ASP.NET Core

Learn how to simplify 2FA integration in ASP.NET Core by generating the QR Code using the QR Plus API, without additional libraries.

13 June/2024
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Two-factor authentication (2FA) enhances security by requiring not just a password but also a second factor, such as a code generated by an authenticator app.

While ASP.NET Core supports 2FA, it doesn’t natively support QR code generation for setting up TOTP (Time-based One-time Password) with authenticator apps. This article will show you how to streamline this process using the QR Plus API.

Why Use QR Codes for 2FA?

QR codes simplify the process of setting up 2FA with an authenticator app. Instead of manually entering a long key, users can scan a QR code, which automatically configures their authenticator app.

Adding QR Codes to the 2FA Configuration Page Using QR Plus

Using an external API like QR Plus can make the implementation straightforward and library-free. Here’s how to do it:

Step 1: Add the Necessary Using Directive

At the top of your Razor page, add the following directive to use the URL encoding:

@using System.Text.Encodings.Web

Step 2: Embed the QR Code in Your Page

Within your 2FA configuration page, use an image tag to embed the QR code. Ensure the TOTP URI is URL-encoded to handle special characters correctly:

<div id="qrCode">
<img src="" />

Step 3: Test Your Application

Make sure to test your application to confirm that the QR code is displayed correctly and can be scanned by authenticator apps.

Microsoft Documentation Overview

The official Microsoft documentation suggests including a library like qrcode.js to generate QR codes for 2FA. This method involves downloading the library, adding it to your project, and writing custom JavaScript to generate the QR code.

Benefits of Using QR Plus

  • Simplicity: No need to install additional libraries.
  • Efficiency: Quick and easy QR code generation.
  • Reliability: External service handles QR code rendering.
  • Cost: QR Plus offers a free and straightforward solution without the need for extra libraries or registration.

Security Considerations

While using an external service like QR Plus is convenient, it’s important to consider the security implications. Ensure that sensitive information, such as TOTP keys, is handled securely and that you trust the external service provider.


By integrating QR Plus for QR code generation, you can significantly simplify the 2FA setup process for your users. This approach is easy to implement and eliminates the need for additional libraries, making it a practical solution for many ASP.NET Core applications.