SignalWire

⚠️ AVOID Deprecated APIs

SignalWire maintains compatibility APIs (LAML/CXML) that should NOT be used for new development:

• LAML endpoints (/laml/) → Use REST API (/api/calling/, /api/video/)
• CXML (XML markup) → Use SWML (YAML/JSON)

This skill documents ONLY modern APIs: REST with JSON, SWML, Relay SDK, AI Agents SDK.

SignalWire Technologies Quick Reference

Practical Knowledge from Production

This skill combines technical API documentation with practical implementation guidance from real-world SignalWire deployments. Each workflow file includes:

• Best Practices - Production-tested techniques and patterns
• Common Patterns - Real-world implementation examples
• Anti-Patterns - What NOT to do, mistakes to avoid
• Production Tips - Deployment, monitoring, and testing insights
• Real-World Examples - Complete working patterns from live applications

These insights come from analysis of 89 SignalWire training videos, LiveWire sessions, and production deployments.

Workflows by Use Case

Getting Started:

• [Authentication & Setup](workflows/authentication-setup.md) | [Number Management](workflows/number-management.md)

Voice Calls:

• [Outbound Calling](workflows/outbound-calling.md) | [Inbound Handling](workflows/inbound-call-handling.md) | [Call Control](workflows/call-control.md)

AI Voice Agents: Start with [Voice AI](workflows/voice-ai.md) overview

• SDK: [Basics](workflows/ai-agent-sdk-basics.md) | [Prompting](workflows/ai-agent-prompting.md) | [Functions](workflows/ai-agent-functions.md) | [Deployment](workflows/ai-agent-deployment.md)
• Best Practices: [Patterns](workflows/ai-agent-patterns.md) | [Error Handling](workflows/ai-agent-error-handling.md) | [Security](workflows/ai-agent-security.md) | [Testing](workflows/ai-agent-testing.md) | [Debug Webhooks](workflows/ai-agent-debug-webhooks.md)

Other:

• [Messaging](workflows/messaging.md) | [Video](workflows/video.md) | [Fabric & Relay](workflows/fabric-relay.md) | [Webhooks & Events](workflows/webhooks-events.md)

Quick Start Patterns

Authentication: HTTP Basic Auth with Project ID (username) + API Token (password)

Space URL: All API requests go to https://{space-name}.signalwire.com

SWML Variables: %{call.from}, %{call.to}, %{params.customfield}, %{args.userinput}

Webhooks: HTTP POST with JSON (callid, callstate, from, to, direction)

Errors: REST returns HTTP status + JSON with error/message. SWML logs to Dashboard.

Key Concepts

Call States: queued → created → ringing → answered → ended

SWML Sections: main (required entry point) | execute (call + return) | transfer (goto)

Resources: Subscribers, AI Agents, SWML Scripts, Video Rooms, SIP Gateways, Relay Apps (created via Dashboard or REST API)

Critical Pattern: Loop Protection

SWML gather/prompt nodes can infinite loop. Always add counters:

- set:
    loop_counter: "{{loop_counter | default(0) | int + 1}}"
- condition:
    if: "{{loop_counter}} > 3"
    then: hangup  # Prevent caller stuck in loop

For complete patterns, see [Inbound Call Handling](workflows/inbound-call-handling.md).

AI Agents SDK Reference

IMPORTANT: For AI agent tasks, start with [Voice AI](workflows/voice-ai.md) - it covers 90% of use cases with examples and best practices.

Only load reference docs for: Complete API parameters, advanced features (Contexts/Steps, Prefabs), platform-specific deployment (Lambda/GCF/Azure), or debugging production issues.

See [Voice AI workflow](workflows/voice-ai.md) "When to Pull Additional Documentation" section for detailed guidance on when to use each reference document.

Finding the Right Workflow

New to SignalWire? → [Authentication & Setup](workflows/authentication-setup.md)

Building AI voice agent? → [Voice AI](workflows/voice-ai.md)

Making/receiving calls? → [Outbound Calling](workflows/outbound-calling.md) or [Inbound Handling](workflows/inbound-call-handling.md)

Debugging webhooks/callbacks? → [Webhooks & Events](workflows/webhooks-events.md)

Need real-time control? → [Fabric & Relay](workflows/fabric-relay.md)

Additional Resources

• Main Documentation: https://developer.signalwire.com/
• GitHub Examples: https://github.com/signalwire
• AI Agents SDK: https://github.com/signalwire/signalwire-agents
• Dashboard: https://{your-space-name}.signalwire.com