Generate a QR code in Go

This is a small repository showing how to generate a QR code, with an optional watermark, in Go.

This project is the complete code behind the "How to Generate a QR Code with Go" tutorial on the Twilio blog.

Prerequisites

To follow along with the tutorial, you don't need much, just the following things:

• Go (a recent version, or the latest, 1.20.5)
• Curl or Postman
• A smartphone with a QR code scanner (which, these days, most of them should have)

Start the application

To start the application, run the following command:

go run main.go

Generate a QR code

To generate a QR code, send a POST request to http://localhost:8080/generate with two POST variables:

• size: This sets the width and height of the QR code
• url: This is the URL that the QR code will embed

The curl example, below, shows how to create a QR code 256x256 px that embeds "https://arstechnica.com", and outputs the generated QR code to data/qrcode.png.

curl -X POST \
    --form "size=256" \
    --form "url=https://arstechnica.com" \
    --output data/qrcode.png \
    http://localhost:8080/generate

You can also watermark the QR code, by uploading a PNG file using the watermark POST variable. Below is an example of how to do so with curl.

curl -X POST \
    --form "size=256" \
    --form "url=https://matthewsetter.com" \
    --form "watermark=@data/twilio-logo.png" \
    --output data/qrcode.png \
    http://localhost:8080/generate