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Custom Gateway Setup 🛠️

Please consider the Private Server mode first. It offers additional privacy features and is not significantly different from a self-built solution—with far fewer setup operations required.

Please note

  • Custom builds are not officially supported
  • No troubleshooting assistance provided

Before You Begin ⚠️

Secure Your Deployment

Default configuration exposes public endpoints. You must implement:

  • Firewall rules
  • HTTPS encryption
  • Additional authentication mechanisms if necessary

Use at your own risk

Prerequisites 📋

  1. 📱 Android Development

    • Android Studio 2023.2+
    • SDK API Level 33

  2. 🔥 Firebase Setup

    • Google Cloud account
    • FCM-enabled project
    • Service account credentials

  3. 🗄️ Database

    • MySQL 8.0+ / MariaDB 10.6+
    • 2GB+ storage allocated

  4. ☁️ Server Infrastructure

    • VPS with public IP
    • Reverse proxy (Nginx/Traefik)
    • Valid SSL certificate

  5. ⚙️ Build Tools

    • Go 1.23+
    • Docker 24.0+

Backend Configuration ⚙️

config.yml
gateway:
  mode: public
fcm:
  credentials_json: |
    {
      "type": "service_account",
      "project_id": "your-project"
    }
Implementation Steps:

  1. Follow Private Server Guide
  2. Set gateway.mode: public
  3. Update FCM credentials

internal/sms-gateway/modules/push/upstream/client.go
- const BASE_URL = "https://api.sms-gate.app/upstream/v1"
+ const BASE_URL = "https://your-main-server.com/upstream/v1"
Build Commands: 
make build  # Binary
make docker-build  # Container

Architecture Requirement

Private servers require at least one public server

Communication flow: Device ↔ Private Server ↔ Public Server ↔ FCM

Android App Customization 📱

  1. Clone Repository 

    git clone https://github.com/capcom6/android-sms-gateway
cd android-sms-gateway

  2. Configure Endpoints
    Edit app/src/main/java/me/capcom/smsgateway/modules/gateway/GatewaySettings.kt by replacing PUBLIC_URL with your main server URL (including path): 

    - const val PUBLIC_URL = "https://api.sms-gate.app/mobile/v1"
+ const val PUBLIC_URL = "https://your-main-server.com/mobile/v1"

  3. Set Unique Application ID
    Modify app/build.gradle by replacing applicationId value with your unique application ID: 

    - applicationId "me.capcom.smsgateway"
+ applicationId "com.yourcompany.smsgateway"

  4. Firebase Integration
    Follow the Firebase Android Setup Guide to get the google-services.json file and add it to app/google-services.json.

  5. Build & Deploy

    ./gradlew assembleRelease

Security Checklist 🔐

  • Implement IP whitelisting
  • Configure HTTPS with HSTS
  • Set up rate limiting
  • Enable audit logging
  • Rotate API keys quarterly

See Also 📚