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Overview

WiFi QR codes allow users to connect to wireless networks instantly by scanning a code, without manually typing network names and passwords. Most modern smartphones automatically detect WiFi QR codes and prompt the user to join the network. This is especially useful for guest networks, businesses, cafes, and events.

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Data Structure

WiFi QR codes use the WifiQrData interface: 
export interface WifiQrData {
  ssid: string;
  password: string;
  security: "WPA" | "WEP" | "nopass";
}
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ssid
string
required
The network name (SSID - Service Set Identifier). Must be 1-32 characters in length.
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password
string
required
The network password. Required for WPA and WEP security types. Minimum 8 characters for WPA, 5 characters for WEP. Maximum 63 characters. Leave empty for open networks (nopass).
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security
'WPA' | 'WEP' | 'nopass'
required
The network security type:
  • "WPA": WPA/WPA2/WPA3 encrypted networks (most common)
  • "WEP": WEP encrypted networks (legacy, not recommended)
  • "nopass": Open networks without password protection

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Encoding Format

WiFi QR codes use a standardized format (from /src/domain/encoders/encoders.ts:25-28): 
const encodeWifi = (data: WifiQrData) => {
  const password = data.security === "nopass" ? "" : data.password.trim();
  return `WIFI:T:${data.security};S:${data.ssid.trim()};P:${password};;`;
};

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Format Specification

The WiFi QR code format follows this structure: 
WIFI:T:<security_type>;S:<ssid>;P:<password>;;
Where:
  • T: - Authentication type (WPA, WEP, or nopass)
  • S: - Network SSID (name)
  • P: - Network password (empty for open networks)
  • ;; - Terminator

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Example Encoding

InputEncoded Output
SSID: “MyNetwork”
Password: “secret123”
Security: “WPA”		WIFI:T:WPA;S:MyNetwork;P:secret123;;
SSID: “GuestWiFi”
Security: “nopass”		WIFI:T:nopass;S:GuestWiFi;P:;;
SSID: “Office-5G”
Password: “password”
Security: “WEP”		WIFI:T:WEP;S:Office-5G;P:password;;

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Validation Rules

The validator (from /src/domain/validation/validators.ts:71-96) enforces these requirements:
  • Cannot be empty or whitespace only
  • Maximum length: 32 characters (WiFi standard)
  • Error messages:
    • “El SSID es obligatorio”
    • “El SSID no puede tener más de 32 caracteres”
For security: "WPA":
  • Password is required (cannot be empty)
  • Minimum length: 8 characters
  • Maximum length: 63 characters
  • Error messages:
    • “La contraseña es obligatoria para redes con seguridad”
    • “La contraseña WPA/WPA2 debe tener al menos 8 caracteres”
    • “La contraseña no puede tener más de 63 caracteres”
For security: "WEP":
  • Password is required (cannot be empty)
  • Minimum length: 5 characters
  • Maximum length: 63 characters
  • Error messages:
    • “La contraseña es obligatoria para redes con seguridad”
    • “La contraseña WEP debe tener al menos 5 caracteres”
    • “La contraseña no puede tener más de 63 caracteres”
For security: "nopass":
  • Password is not required and will be ignored in encoding
  • No password validation is performed

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Validation Implementation

export const validateWifiQr = (data: WifiQrData): ValidationResult => {
  const errors: Record<string, string> = {};

  if (!data.ssid || data.ssid.trim() === "") {
    errors.ssid = "El SSID es obligatorio";
  } else if (data.ssid.trim().length > 32) {
    errors.ssid = "El SSID no puede tener más de 32 caracteres";
  }

  if (data.security !== "nopass") {
    if (!data.password || data.password.trim() === "") {
      errors.password = "La contraseña es obligatoria para redes con seguridad";
    } else if (data.security === "WEP" && data.password.length < 5) {
      errors.password = "La contraseña WEP debe tener al menos 5 caracteres";
    } else if (data.security === "WPA" && data.password.length < 8) {
      errors.password = "La contraseña WPA/WPA2 debe tener al menos 8 caracteres";
    } else if (data.password.length > 63) {
      errors.password = "La contraseña no puede tener más de 63 caracteres";
    }
  }

  return {
    isValid: Object.keys(errors).length === 0,
    errors,
  };
};

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Usage Example

import { QrTypeKey } from "./domain/types/qr";
import type { WifiQrData } from "./domain/types/qr";
import { encodeQrData } from "./domain/encoders/encoders";
import { validateWifiQr } from "./domain/validation/validators";

// Create WiFi QR data for a WPA network
const wifiData: WifiQrData = {
  ssid: "CoffeeShop-Guest",
  password: "welcome2024",
  security: "WPA"
};

// Validate the data
const validation = validateWifiQr(wifiData);
if (!validation.isValid) {
  console.error("Validation errors:", validation.errors);
}

// Encode the data
const encodedWifi = encodeQrData(QrTypeKey.Wifi, wifiData);
// Result: "WIFI:T:WPA;S:CoffeeShop-Guest;P:welcome2024;;"

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Common Use Cases

  • Guest Networks: Provide easy WiFi access for visitors
  • Businesses: Share network credentials with customers (cafes, restaurants, hotels)
  • Events: Allow attendees to connect quickly at conferences or gatherings
  • Offices: Simplify onboarding for new employees
  • Home Networks: Share WiFi with guests without revealing the password verbally

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Security Considerations

WiFi QR codes contain your network password in plain text. Anyone who can scan the code can access your network.
  • Use WiFi QR codes only for guest networks or networks you intend to share publicly
  • Consider using a separate guest network isolated from your main network
  • For WPA networks, ensure you’re using WPA2 or WPA3 on your router
  • Avoid using WEP encryption as it’s outdated and insecure
  • Regularly rotate guest network passwords

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