Set up your cloud SMS relay in under 10 minutes. Follow these steps to pair your Android device, send your first message, and connect your tools.
Sign up for a free Pairfon account at web.pairfon.com/signup.
Every account starts with a 14-day free trial on your selected plan. No credit card required during the trial period.
Go to the Mobile App page in your dashboard to download the latest Pairfon APK.
The APK is about 8 MB. If you're downloading directly on the phone, just open the download link in Chrome on your phone.
In your dashboard, go to the Mobile App page to see the QR code.
The pairing links your phone to your Pairfon account over a secure WebSocket connection. The phone stays connected in the background, even when you close the app. Android will show a persistent notification confirming the connection.
If your phone has dual SIM, choose which SIM Pairfon should use:
If you select "Both," you can choose which SIM to use per message from the dashboard or specify it in API calls. This is useful if you have separate numbers for different purposes (e.g., sales vs. support).
Go to the Chat page in your dashboard:
You should see the message status update to "Sent" within a few seconds. If the recipient replies, the reply appears in the same conversation thread. Send a test to your own secondary number or a colleague to verify everything works.
Forward inbound SMS to any URL in real time:
Every inbound SMS matching your filters will POST a JSON payload to your URL with the sender, message, device, SIM, and timestamp. The payload looks like:
{"event":"sms.received","from":"+15551234567","body":"Hello","device":"Office Phone","sim":"SIM 1","timestamp":"..."}
Your endpoint should respond with HTTP 200 within 10 seconds. If it fails, Pairfon retries up to 3 times with exponential backoff.
Connect Pairfon to your favorite tools:
Go to the Integration page in your dashboard for direct connect links. Each integration has its own setup flow, but all take under 5 minutes to configure.
For programmatic access:
Authorization: Bearer your-api-keyThe API lets you send SMS, list devices, check message status, and manage webhooks programmatically. Common endpoints:
POST /api/v1/sms/send — Send an outbound SMSGET /api/v1/devices — List paired devices and their statusGET /api/v1/sms — Retrieve message historyCheck that the Pairfon app is running on your phone (look for the persistent notification). Make sure the phone has a stable internet connection (Wi-Fi or mobile data). Try opening the app and tapping "Reconnect." If the phone is behind a strict corporate firewall, it may block WebSocket connections — switch to mobile data to test.
This means the server received the message but can't reach the phone. Check device connectivity (see above). If the phone was recently restarted, open the Pairfon app once to re-establish the connection. Queued messages will send automatically once the phone comes back online.
Verify your carrier plan has active SMS capability. Check if you have sufficient balance (for prepaid plans). Make sure the recipient number includes the country code. If you're sending to international numbers, confirm your carrier supports international SMS.
Make sure your phone's camera has permission to be used by the Pairfon app. Try increasing screen brightness on the computer displaying the QR code. If the QR code has expired, refresh the Mobile App page to generate a new one.
Verify the webhook URL is publicly accessible (not localhost). Check that your server returns HTTP 200 within 10 seconds. Look at the webhook delivery logs in your Pairfon dashboard — failed deliveries show the HTTP status code returned by your server.
Make sure your phone runs Android 8.0 or later (Settings → About Phone → Android Version). Ensure you have at least 50 MB of free storage. If you get a "Parse error" during install, re-download the APK — the file may have been corrupted during transfer.
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