Install the simwire app, scan a QR from your terminal, and your SIM starts answering to your code.
The app installs outside the Play Store, so verify the download rather than trusting it:
sha256sum simwire-0.2.0.apk 3e52d50f06f4099551a7da4f5c457492899287a01d56aec7aeb35a5fb5e295c7
On macOS, shasum -a 256 simwire-0.2.0.apk. The digest is also
published as a file next to the APK on the release page.
The app comes straight from us, not from the Play Store, so Android asks one extra confirmation.
Android will ask you to allow installs from this source. Allow it once; you can revoke it right after.
Open the app, go to Health, and turn the three checks green. Each one is explained below.
Run npx simwire pair in your terminal and scan the QR. Phone and computer must share the same Wi-Fi.
simwire asks for exactly what a local SMS gateway needs, and nothing else.
This is the product. Your code sends texts through your SIM, and incoming texts are forwarded to your computer. Messages are never sent anywhere else.
Used only to list your SIM cards and carriers, so you can route each message through the SIM you choose (dual-SIM).
Opens only when you scan the pairing QR, never in the background. You can deny it afterwards; pairing stays valid.
Android requires a permanent notification for apps that keep working in the background. It shows the gateway is alive; it never pings you.
Without it, Android kills the gateway a few minutes after the screen turns off, and your code loses the connection. This is the number one fix when "it stopped working".
The app announces itself on your Wi-Fi so your computer finds it without typing an IP. All traffic stays between your two devices.