SMS Forwarder
Auto-Forward Android SMS to Webhook, Email & Phone

// use-cases.md

// features.md

// tech-stack.md

// technical-flow.md — SMS received → forwarded, step by step

1. 01

   Detection — SmsReceiver (priority 999)

   A high-priority BroadcastReceiver registered for android.provider.Telephony.SMS_RECEIVED intercepts every incoming SMS before other apps. Calls goAsync() to avoid ANR on the main thread, buying 10 seconds of background processing time.

2. 02

   Extraction — getMessagesFromIntent()

   Uses Telephony.Sms.Intents.getMessagesFromIntent() to parse raw PDU data and extract sender address, message body, and Subscription ID (for Dual-SIM identification). Multi-part messages are concatenated automatically.

3. 03

   Rule Loading — RuleRepository on Dispatchers.IO

   A Kotlin Coroutine on Dispatchers.IO queries RuleDao (Room 2.8.4) for all enabled ForwardingRule entities. No main thread blocking. Results are filtered in-memory.

4. 04

   Filtering — processMessage()

   Each rule is evaluated: senderMatches() (exact/partial), keywordMatches() (case-insensitive body search), simMatches() (Subscription ID). All three must pass. A rule with no sender/keyword filter matches all messages.

5. 05

   Loop Validation — RuleValidator

   RuleValidator analyses the rule graph to detect circular forwarding chains (A→B→A). If a loop is found, the forward is blocked, the rule is flagged red in the database, and LiveData propagates the warning to the UI instantly.

6. 06

   Template Formatting — formatMessage()

   Resolves placeholders: {sender} → originating number/ID, {body} → full message, {OTP} → auto-detected 4–8 digit code, {regex_group_N} → custom Regex capture. Webhook JSON templates are also rendered here.

7. 07

   Execution — Forwarder interface dispatch

   Rule destination type dispatches to the concrete implementation: SmsForwarder → SmsManager.sendTextMessage(). EmailForwarder → javax.mail SMTP session. WebhookForwarder → OkHttp 4.12.0 POST with JSON body and optional custom headers.

// comparison.md — SMS Forwarder vs competitors

// highlights.md

// permissions.md

// All permissions are declared in AndroidManifest.xml with clear purpose

// faq.md — 13 questions — click to expand

What is an SMS Forwarder app for Android?

An SMS Forwarder is an Android app that automatically intercepts incoming text messages and relays them to another destination — such as a webhook URL, email inbox, or another phone number — without any manual action. SMS Forwarder v3.4 uses a high-priority BroadcastReceiver (priority 999) and a persistent ForegroundService, ensuring zero missed messages even with the screen off. No root required.

How do I forward SMS to a webhook URL on Android?

Download the free APK, install it, tap + (FAB) to add a rule, choose Webhook as destination, paste your URL (n8n Production URL, Zapier Catch Hook, Make.com webhook, your own REST API), set any sender/keyword filter, and toggle ON. Enable Expert Mode to customise the JSON payload shape and add HTTP headers like Authorization: Bearer TOKEN. The app POSTs {sender, body, timestamp} and any extracted values.

How do I automatically forward OTP codes to email?

Go to Settings → SMTP Configuration and enter your mail server details (host, port, username, password). Then add a rule: choose Email destination, enter your email address. Set sender filter to your bank's ID (e.g. "HDFC") or keyword "OTP". Enable Auto-OTP extraction mode. The {OTP} placeholder will contain the extracted code. Every matching SMS is forwarded to your inbox within seconds — completely automatically, even when your phone is locked.

How do I forward SMS to n8n or Zapier from Android?

In n8n: create a Webhook node → copy the Production URL. In Zapier: Webhooks by Zapier → Catch Hook → copy the URL. In Make.com: add a Custom Webhook module → copy the URL. Then in SMS Forwarder: add a rule, choose Webhook, paste the URL. Enable Expert Mode to add Authorization headers or customise the JSON template to match your automation platform's expected format. The app will trigger your workflow on every matching SMS in real time.

Does SMS Forwarder work in the background on Android 10, 11, 12, 13, 14, 15?

Yes. ForwardingService is a ForegroundService with a persistent status bar notification — Android cannot kill it automatically. BootReceiver restarts it after reboots. START_STICKY tells Android to recreate it if killed by memory pressure. The app prompts you to disable battery optimisation on first launch via Settings.ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS. Additionally, SmsReceiver (priority 999) intercepts messages independently of the service state.

Does SMS Forwarder support Dual-SIM phones?

Yes. The app reads the Subscription ID from the incoming SMS intent to identify which SIM received it. Each forwarding rule can independently target Any SIM, SIM 1 only, or SIM 2 only. When forwarding to another phone number, you can also choose which SIM to use for sending the outgoing message.

Is SMS Forwarder private? Are my messages stored on a server?

SMS Forwarder is 100% privacy-first. All SMS processing happens locally on your device — no messages, no metadata, no rule data is ever sent to the developer or any third-party server. There is no analytics, no telemetry, no ads. The optional Google Drive backup uses DriveScopes.DRIVE_FILE (restricted scope — the app can only access files it created) and saves only your rule configurations to your own Drive — completely inaccessible to the developer.

Does SMS Forwarder require root?

No. SMS Forwarder uses only standard Android APIs — the SMS_RECEIVED broadcast intent and SmsManager. It works on any non-rooted Android 10+ device from any manufacturer (Samsung, Xiaomi, OnePlus, Realme, Vivo, Oppo, stock Android). No modifications to the system partition are needed or made.

What is Loop Protection and why is it important?

Without loop detection, if Phone A (running SMS Forwarder) forwards to Phone B (also running SMS Forwarder), and Phone B has a rule that forwards back to Phone A, you get an infinite SMS chain that can generate hundreds of messages per minute. RuleValidator detects these circular graphs before execution and blocks the forward. Affected rules are marked with a red warning indicator in the MainActivity card list so you can fix the configuration.

How does the Regex extraction feature work?

In AddEditRuleActivity, choose "Regex" as the extraction mode and enter a regular expression with capture groups. SMS Forwarder applies it to every matching message body and exposes the captured groups as template variables. Useful for extracting: transaction amounts from bank alerts, order IDs from delivery SMS, custom OTP formats that Auto-OTP doesn't detect, or any structured data from a specific SMS format.

Is SMS Forwarder free? What is the pricing?

Yes, SMS Forwarder v3.4.0 is completely free to download and use — with no in-app purchases, no ads, no subscriptions, and no accounts required. The app is proprietary, closed-source, and distributed directly on GitHub as a pre-compiled APK.

Is SMS Forwarder available on the Google Play Store?

SMS Forwarder is distributed as a direct APK download from GitHub, not through the Google Play Store. This is common for SMS-reading apps because Google Play has strict restrictions on apps that access SMS content. Download the APK directly from the GitHub Releases page. Google Play Protect may warn you — this is a standard false positive for SMS-permission apps from trusted repositories on GitHub.

What Android version is required?

SMS Forwarder v3.4.0 requires Android 10 (API 29) or higher. It targets Android 15 (API 36). Tested and confirmed working on Android 10, 11, 12, 13, 14, and 15. Compatible with all major Android OEM skins: One UI (Samsung), MIUI/HyperOS (Xiaomi), OxygenOS (OnePlus), Realme UI, ColorOS (Oppo), OriginOS (Vivo), and stock Android.