A lightweight SIP call bridging tool for VOIP.MS that connects two phone numbers via automated transfer.

• 🔗 Bridges two phone calls using SIP REFER method
• 📞 HD voice support with G.722 codec
• 🚀 Fast and lightweight Go implementation
• 🔒 Secure digest authentication
• 📦 Nix flake for reproducible builds
• 🖥️ Cross-platform support (macOS, Linux)

# Run directly
nix run github:ak2k/siplink -- 15551234567 15559876543

# Install to profile
nix profile install github:ak2k/siplink

git clone https://github.com/ak2k/siplink
cd siplink
go build -o siplink main.go

Set your VOIP.MS credentials as environment variables:

export VOIPMS_USER='your_voipms_username'
export VOIPMS_PASS='your_voipms_password'
export VOIPMS_SERVER='chicago.voip.ms'  # Optional, defaults to chicago

See VOIP.MS Recommended POPs for the full list of available servers and their locations.

# Basic usage
siplink <source_number> <destination_number>

# Example
siplink 15551234567 15559876543

# With environment override
VOIPMS_SERVER=toronto.voip.ms siplink 14161234567 14169876543

Using rbw, a fast Bitwarden CLI:

1. Store your credentials in Bitwarden:

   • Item name: voipms (or any name you prefer)
   • Custom fields:
     • voipms_user: Your VOIP.MS username
     • voipms_pass: Your VOIP.MS password

2. Install and configure rbw:

   # Install rbw
   nix-env -iA nixpkgs.rbw  # or add to your nix configuration
   
   # First-time setup
   rbw config set email [email protected]
   rbw login
   rbw sync

3. Use with siplink:

   # Set credentials from Bitwarden
   export VOIPMS_USER=$(rbw get "voipms" --field voipms_user)
   export VOIPMS_PASS=$(rbw get "voipms" --field voipms_pass)
   export VOIPMS_SERVER="chicago.voip.ms"  # or your preferred server
   
   # Run siplink
   siplink 15551234567 15559876543

1. Registration: Authenticates with VOIP.MS SIP server
2. Call Initiation: Places call to first number
3. Transfer: Uses SIP REFER to transfer call to second number
4. Monitoring: Tracks transfer progress via NOTIFY messages
5. Completion: Exits cleanly when transfer succeeds

• VOIP.MS account with sub-account credentials
• Go 1.21+ (for building from source)
• Nix (for nix-based installation)

Use 11-digit format for US/Canada numbers: 1XXXXXXXXXX

• Verify credentials are correct
• Check if your IP is whitelisted in VOIP.MS settings
• Try a different server if connection fails

Some carriers may not support SIP REFER transfers. Test with known working numbers first.

MIT License - see LICENSE file for details

Pull requests welcome! Please ensure:

• Code follows Go conventions
• Tests pass
• Documentation is updated
• Both flake.lock and vendorHash are updated when dependencies change

Built with SIPGO - a modern SIP library for Go.