QR I/O


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How to Use QR I/O

QR I/O is a progressive web app for scanning, creating, and sharing QR codes. Works offline after first load.

Buttons

Scan
Opens the camera to scan a QR code. The scanned content appears in the text area. If auto-send is configured, the data is automatically sent to the configured server.
Show
Displays the text from the text area as a full-screen QR code. The QR code is maximized for easy scanning from a distance. Tap anywhere to close.
Email
Opens your default email client with the text content as the email body. Great for quickly emailing scanned QR code content or notes to yourself or others.
ShareTo
Opens the system share dialog to share the text content to any app that supports sharing (messages, notes, social media, etc.). This button is only visible on devices that support the Web Share API.
Share
Sends the attached image to a configured server via WebSocket or HTTP POST. Requires configuration - scan a Config QR code first, then select an image file to share.

Form Controls

Text Area
Enter or paste text that you want to convert to a QR code or share. Scanned QR codes also appear here.
File Input
Attach an image file for sharing.
Clear
Clears the text area and removes any attached image.
Save
Saves the current text to local storage for later use.
Config
Opens the camera to scan a configuration QR code. This sets up auto-send mode where scanned QR codes are automatically sent to a WebSocket or HTTP endpoint. Configuration is saved to browser storage, so this only needs to be done once.

Quick Pairing with Receiver

The easiest way to set up data transfer is to pair with the QR Receiver:

  1. Open the QR Receiver on your computer
  2. Tap Config here on your phone
  3. Scan the Config QR displayed on the receiver
  4. This app auto-configures and connects - no typing needed!
  5. Now scan any QR code and it appears on the receiver in real-time

Manual Configuration

To manually enable auto-send mode, scan a configuration QR code containing JSON:

{"mode":"auto-send","url":"wss://your-server.com"}

Supported URL schemes: wss:// (WebSocket), https:// (HTTP POST), or mqtts:// (MQTT over WSS)

MQTT (Public Broker)

You can enable MQTT to send scanned QR data to a public MQTT broker (broker.emqx.io). This must be explicitly enabled in the configuration section below the Config button.

Enable MQTT
Check the "Enable MQTT" checkbox to connect to the public broker. Your data will be sent to a unique topic.
Topic Format
Topics are generated as qrio/XXX-XXX-XXX where XXX are random Base58 characters. Share this topic with receivers.
Privacy Note
The public broker is accessible to anyone. Only enable this if you understand that your scanned data will be sent over a public network. Use the topic as a simple form of access control.
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