How SIMtrix Works

The Bridge Concept

SIMtrix acts as a real-time bridge between your Bitrix24 CRM and your physical Android phone. Unlike VoIP solutions that require virtual phone numbers, SIMtrix uses your existing SIM card — your real phone number, your existing carrier plan, your local caller ID. The server orchestrates communication but never stores your call content or SMS messages.

Outbound Call Flow

When you click a phone number in Bitrix24, the following happens in real-time: (1) Bitrix24 sends a call request to the SIMtrix server via REST API. (2) The SIMtrix server instantly pushes a command to your Android phone via WebSocket (or FCM as fallback). (3) The Android app receives the command and initiates a native phone call using your SIM card. (4) The call connects and optionally starts recording. (5) When the call ends, the Android app reports duration and recording to the server. (6) The server logs the completed call in Bitrix24 CRM on the contact timeline.

Inbound Call Flow

When someone calls your SIM card number: (1) The Android phone detects the incoming call. (2) If enabled, a CRM overlay shows the caller information from Bitrix24 (name, company, deal). (3) After the call ends, the Android app sends call details to the SIMtrix server. (4) The server matches the phone number to a Bitrix24 contact and logs the call on their timeline. (5) If the number is unknown, SIMtrix can optionally create a new lead in Bitrix24.

SMS Flow

Outbound SMS: Click "Send SMS" from a contact or deal card in Bitrix24. The command goes to the server, then to your phone, which sends the SMS via your SIM card. The message is logged on the contact timeline in Bitrix24. Inbound SMS: When your phone receives an SMS, the app forwards it to the SIMtrix server, which logs it on the matching contact timeline in Bitrix24 — creating a full two-way conversation history.

Data Privacy

SIMtrix follows a strict "bridge not storage" principle. Call recordings and SMS content are only stored in your Bitrix24 CRM and on your Android phone. The SIMtrix server processes data in transit but does not permanently store message content or call recordings. Your data stays under your control.

الأسئلة الشائعة

Is there any delay when making calls?

The communication between Bitrix24, SIMtrix server, and your phone happens in under 1 second thanks to persistent WebSocket connections. The actual call connects at normal cellular speed.

What happens if my phone loses internet?

If the phone temporarily loses connectivity, SIMtrix uses Firebase Cloud Messaging (FCM) as a fallback to deliver commands. FCM can wake the app and re-establish the connection. During a complete internet outage, commands are queued on the server and delivered once the phone reconnects.

Does SIMtrix use my mobile data?

SIMtrix uses a minimal amount of data for command signaling — typically under 5 MB per month for the control channel. Call recordings, if enabled, use additional data when uploading to Bitrix24 (roughly 0.5 MB per minute of recorded audio).