HK Relay: Turn Any Android Phone Into an SMS Gateway

Multi-Channel Support

HK Relay supports three messaging channels:

• SMS — standard text messages via SIM card
• WhatsApp Personal — messages through your personal WhatsApp account
• WhatsApp Business — messages through WhatsApp Business app

Switch between channels based on your use case — OTPs via SMS, customer notifications via WhatsApp Business, personal messages via WhatsApp.

24/7 Reliability Features

The app is engineered to run non-stop:

// Recovery mechanisms built into HK Relay:
// 1. Foreground Service — persists through memory pressure
// 2. Wake Lock — prevents CPU sleep during message processing
// 3. WiFi Lock — maintains network connection
// 4. Watchdog Alarm — checks service health every 5 minutes
// 5. Boot Auto-Start — restarts after device reboot
// 6. Network Change Listener — auto-reconnects on network switch
// 7. Socket.IO Auto-Reconnect — handles server disconnections

In real-world testing, HK Relay maintains uptime of 99.9%+ without manual intervention.

Security First

• Token-based authentication — only authorized phones can connect
• Encrypted WebSocket (WSS) — all communication is encrypted in transit
• No message storage — messages are processed and forgotten
• Server-side validation — every request is validated before processing

Use Cases

OTP & 2FA Delivery Send verification codes to users during registration or login. Works perfectly with our Developer Portfolio & SaaS Platform's authentication system.

Business Notifications Automatically notify clients about:

• Order confirmations and shipping updates
• Invoice due dates and payment receipts
• Appointment reminders
• Service status updates

Marketing Campaigns Send promotional messages to opted-in customers. Perfect for announcing new products, sales, or events.

Personal Automation Automate personal messaging:

• Scheduled birthday/anniversary messages
• Automated responses to specific keywords
• Integration with smart home systems

Integration with Developer Portfolio

HK Relay integrates seamlessly with our Developer Portfolio & SaaS Platform:

// Server-side: Send SMS via HK Relay
import { io } from "socket.io-client";

const socket = io("wss://your-server:3001", {
  auth: { token: "device-auth-token" },
});

// Send SMS
socket.emit("send_sms", {
  to: "+91XXXXXXXXXX",
  message: "Your OTP is 847291",
  channel: "sms", // or "whatsapp" or "whatsapp_business"
});

// Listen for delivery confirmation
socket.on("delivery_status", (data) => {
  console.log(`Message to ${data.to}: ${data.status}`);
});

The platform's admin dashboard shows real-time device status, message queues, and delivery reports.

Requirements

• Android 8.0+ (API 26)
• Active SIM card with SMS plan
• Internet connection (WiFi or mobile data)
• WhatsApp installed (for WhatsApp messaging)
• ~30MB storage
• Server: Developer Portfolio Platform with Relay module + Socket.IO server

Pricing

Single Device License: $79 (Compare at $129)

Multi-device licenses available for businesses that need redundancy or high volume — contact us for custom pricing.

Get Started

1. Purchase HK Relay from hardikkanajariya.in
2. Install the APK on your Android device
3. Configure the server URL and authentication token
4. Start sending messages programmatically

Related reads:

• Socket.IO Real-Time Communication — the technology powering HK Relay
• Developer Portfolio SaaS Platform — the server that manages HK Relay
• HK AIR IoT Controls — our other native Android companion app

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Stop paying per message. HK Relay — one-time $79, unlimited messages. Part of the Developer Portfolio ecosystem.