Reliability
Why a phone disconnects with the screen off
Implementation scenario · This is an example implementation, not a story about a named customer. Results depend on your integration, phone, network and carrier.
AI-generated scenario illustrationThe problem
Android and manufacturer settings can restrict background apps. If opening the app restores connectivity, check phone settings as well as the server.
Build the solution
Allow SMS and notifications, enable the gateway and its battery-optimisation exemption. On Huawei and Honor, check auto-launch, secondary launch and background operation. Keep internet access and stable charging.
Check before launch
Test screen-off operation on the actual model. A force-stopped app needs manual opening. No service can promise continuous connectivity on every Android device.
How SIM Bridge works
Your backend creates a job through the API, and the connected Android sends SMS through your SIM. Store the message ID in your system and receive status changes through a webhook. A queued job is not yet a sent message: the phone must be available and the carrier must accept it.
Start with your own test number. Check Android permissions, screen-off connectivity, retries with the same Idempotency-Key, and unknown-status handling. Keep API keys out of browser code and public repositories.
