How the Android SMS Gateway Solves the Delivery Cost Problem

The problem with traditional SMS gateways

Sending SMS in volume comes at a cost. Traditional SMS gateways typically charge between €0.03 and €0.08 per message sent, depending on the volume and the carrier.

For a company sending 5,000 messages a month, this represents between €150 and €400 monthly just in delivery costs — before any management platform is considered.

There is an alternative that many companies are unaware of: using an Android smartphone with the company's SIM card as an SMS gateway. Messages are sent as normal SMS by the carrier, at the cost of the SIM card plan — which is often unlimited or has a marginal cost.

How the Android SMS Gateway works in WhatSMS

WhatSMS includes an Android application developed specifically for this purpose. The architecture is simple:

Step 1: The WhatSMS platform receives messages that need to be sent and places them in a queue.

Step 2: The Android smartphone — a dedicated device or an old phone — is plugged in, with the application running in the background.

Step 3: The Android app queries the platform's queue every 5 seconds and sends the messages via Android's native SMS, using the company's SIM card.

Step 4: Delivery reports are sent back to the platform, which updates the status of each message.

Communication between the Android app and the platform is done via HTTPS. The phone does not need to have a static IP or open ports — it is always the phone that initiates communication with the server.

10-minute setup

What you need

• An Android smartphone (Android 7 or higher) with an active SIM card
• The SIM card must have SMS sending capability
• Internet connection (mobile data or Wi-Fi)
• An active WhatSMS account

Step-by-step guide

Step 1 — Generate the pairing QR code: On the WhatSMS platform, go to Settings → SMS Gateway → Add device. A unique QR code is generated with a pairing token.

Step 2 — Install the Android application: Download the WhatSMS Gateway application from the downloads page (available as an APK for business installation). Upon opening, tap Pair device and point at the QR code.

Step 3 — Authorize permissions: The app needs permission to send SMS and access network status.

Step 4 — Keep it powered: Place the device on charge and enable the Disable battery optimization option for the app. The app shows the Active status when it is communicating correctly with the platform.

Advanced features: Dual SIM

The WhatSMS Gateway supports Dual SIM devices. You can configure which SIM card sends the messages — useful if you have two company numbers with different rates, or if you want to separate marketing sends from transactional sends.

The configuration is done directly in the Android app, in the SIM Settings section.

Monitoring and alerts

The WhatSMS platform monitors the status of the device in real time:

• Battery: current battery level of the device.
• Last signal: when the device last communicated with the platform.
• Messages sent: counter of messages sent in the last 24 hours.
• Connection status: Online, Offline, or No Network.

If the device goes offline for more than 5 minutes, the platform can send an email or WhatsApp alert to the administrator.

When it makes sense to use the Android SMS Gateway

This solution is ideal for:

• Companies with medium volumes (500–10,000 SMS/month) where traditional gateway costs are significant.
• Businesses with generous carrier plans — some corporate plans include unlimited SMS.
• Startups and SMEs that want to keep operational costs low without sacrificing professional features.

It is not ideal for very high volumes (more than 50,000 SMS/month) or for cases where a shortcode is required.

Combination with WhatsApp

In most companies, the Android SMS Gateway works in complement with WhatsApp. WhatsApp handles conversations; SMS is used for critical reminders where guaranteed delivery is a priority.

The WhatSMS platform allows you to manage both channels from the same dashboard, with automatic routing rules: if the customer has WhatsApp, the message goes via WhatsApp; if not, it goes via SMS.