Receive & manage your texts in NubianMail.

Setting it up

Six steps, once.

Four on the phone, one in NubianMail, then one last one back on the phone. Keep both to hand.

1. 1

   Step 1: Install SMS Gateway for Android

   It is free and open source, and it needs Android 5.0 or later. We host the installer here, so the download comes from NubianMail — it is version 1.77.4, the build the project released on 2026-10-19, exactly as they signed it.

   1. Open www.nubianmail.com/phone-app on the phone itself. It downloads the installer (12.7 MB).
   2. Android will say it can't install unknown apps from your browser. Tap the prompt, turn on Allow from this source, and come back. Then open the downloaded file and tap Install.
   3. If Play Protect blocks it: Play Store → your profile picture → Play Protect → Settings → turn off Scan apps with Play Protect, install, then turn it straight back on.

   Download the app

   Version 1.77.4 · 12.7 MB · SHA-256 c10d266aa34ef57ac904b0e8159543dc5d9c07d76f7697aad483371fc9a3b9e4

   Prefer to get it from the project instead? Its documentation is at docs.sms-gate.app (opens in a new tab), and this is the release our copy was taken from. Take app-release.apk and nothing else: the file named app-insecure allows unencrypted connections and its own authors say not to use it, and the .aab files are Play Store bundles a phone cannot install.

2. 2

   Step 2: Let it read your texts, and keep it awake

   Open the app. It asks for permissions as it needs them — grant all of them, then stop Android from putting it to sleep.

   1. SMS permissions. Allow Receive SMS (this is the one that makes texts appear in NubianMail) and Send SMS (this is what lets you reply from your own number). Phone permission is optional and only picks the right SIM on a dual-SIM handset.
   2. If Allow is greyed out, Android is blocking it — not refusing it. An app installed from a download rather than from a store cannot be handed the SMS permission until you say so, and you get a dialog headed App was denied access. Go to Android Settings → Apps → SMSGate → the ⋮ menu (top right) → Allow restricted settings, confirm with your PIN or fingerprint, and the Allow button comes back to life. That menu item only appears once the permission has been blocked at least once, so this order matters.
   3. Battery. Android Settings → Apps → SMS Gateway → Battery → Unrestricted. The wording varies by phone — Samsung, Xiaomi and OnePlus each hide it somewhere different, so look for anything called battery optimisation, sleeping apps or background restrictions and exempt the app wherever you find it.

   Skip the battery step and nothing breaks today — Android stops the app days later, and texts quietly stop arriving with no error anywhere. It is the most common reason this setup goes quiet.

3. 3

   Step 3: Turn RCS off in Google Messages

   RCS is Google's chat protocol, not SMS, and RCS messages never reach the app at all. With RCS on, texts from other Android phones will not appear in NubianMail. With it off, those phones fall back to SMS and the messages come through.

   1. Open Google Messages → tap your profile picture (top right) → Messages settings → RCS chats → turn RCS chats off. On older versions that entry is called Chat features.
   2. To check it worked, open any conversation and look at the send button: it should say it will send by SMS, not by Wi-Fi or mobile data.
   3. Do this before your first test, not after. Recent iPhones send RCS too, so a test message from an iPhone is invisible to the app just as an Android's is. We watched exactly that happen: the text arrived in Google Messages and never reached NubianMail, until RCS went off and the same message came straight through.

   Google warns that turning RCS off removes you from any RCS group chats you are in. You also lose typing indicators, read receipts and full-quality pictures on that handset — that is the real price of this feature, and it is yours alone to pay. Nobody who texts you has to change anything.

4. 4

   Step 4: Turn on Cloud server

   This is what lets NubianMail reach your phone. There is no account to make and nothing to pay — no email, no phone number, no registration.

   1. In the app, on the Home tab, turn on Cloud server.
   2. Tap the Offline button. It connects and changes to Online.
   3. A username and password now appear in that same Cloud server section. They are generated for you the first time it connects. Keep them on screen for the next step.

   Still says Offline? It needs internet, and it uses Google Play Services where they exist. On a phone without them it falls back automatically — Settings → Cloud server → Notification channel → SSE Only, then restart the app.

5. 5

   Step 5: Link the phone in NubianMail

   Now at your computer, in NubianMail: Texts → Connect TxtYa, and find Your own phone's texts.

   1. Fill in Your mobile number — the number on the SIM in that phone.
   2. Paste the username and password from step 4. Self-hosting the gateway instead of using Cloud server? Put its address in Server.
   3. Press Link this phone. NubianMail registers itself with your phone — there is no terminal and no command to run. Your phone shows a notification confirming a webhook was added.

   NubianMail then shows a Webhook URL and a signing key. The signing key is shown once and never again, so copy it before you leave the page. If you do lose it, unlink and link again.

6. 6

   Step 6: Paste the signing key into the app

   Back on the phone: Settings tab → Webhooks → Signing Key. Paste the key from step 5 and save.

   This is how NubianMail knows a text really came from your phone and not from someone pretending to be it. Until it matches, texts arrive and are refused — so this step is not optional.