Agentifact assessment — independently scored, not sponsored. Last verified Mar 6, 2026.
Twilio Voice
Twilio Programmable Voice is the industry-standard telephony API for building voice AI agents that make and receive phone calls over PSTN and VoIP. It supports TwiML (XML-based call control), WebSockets for streaming audio to AI models in real time, IVR flows, conference calling, call recording, and ASR in 120 languages. Twilio is the underlying telephony layer used by many voice AI platforms including Retell AI and Vapi. PAYG pricing is $0.013/min outbound and $0.0085/min inbound (US); phone numbers start at $1.15/mo. Volume discounts and committed-use pricing are available for enterprise.
Solid choice for most workflows
You need reliable PSTN and VoIP connectivity to build voice AI agents that make outbound calls, handle inbound IVR, and stream real-time audio to LLMs.
Excellent global reliability and low latency via Super Network; PAYG at $0.013/min outbound US; real-time streaming works flawlessly for AI but requires solid WebSocket handling; volume discounts kick in at scale.
You want to embed programmable voice features like IVR, speech recognition, and secure payments into customer-facing apps without building telephony infrastructure.
Highly customizable with quick prototyping (few lines of code); PCI-compliant payments are seamless; global edge locations minimize latency but expect ~1-2s initial call setup.
Per-minute PAYG billing
Costs $0.0085-$0.013/min (US) plus $1.15/mo per number; no free tier for production voice; enterprise committed-use needed for high volume to avoid bill shocks.
Phone number regulations
Local regs require compliance for numbers in each country (e.g., A2P 10DLC in US); non-compliance leads to blocks or fines—check Twilio's country guide and Trust Hub before global rollout.
Twilio wins on global scale and AI streaming ecosystem; Vonage is cheaper for basic calls.
Pick Twilio when building voice AI agents needing real-time WebSockets and Retell/Vapi integration.
Pick Vonage for simple IVR or low-volume apps prioritizing cost over features.
Trust Breakdown
What It Actually Does
Twilio Voice lets you add phone calling to apps so they make, receive, and handle calls worldwide. It supports features like voice menus, call recording, conferences, and real-time audio streaming.[1][2][4]
Twilio Programmable Voice is the industry-standard telephony API for building voice AI agents that make and receive phone calls over PSTN and VoIP. It supports TwiML (XML-based call control), WebSockets for streaming audio to AI models in real time, IVR flows, conference calling, call recording, and ASR in 120 languages. Twilio is the underlying telephony layer used by many voice AI platforms including Retell AI and Vapi.
PAYG pricing is $0.013/min outbound and $0.0085/min inbound (US); phone numbers start at $1.15/mo. Volume discounts and committed-use pricing are available for enterprise.
Fit Assessment
Best for
- ✓voice-calling
- ✓telephony
Score Breakdown
Protocol Support
Capabilities
Governance
- prompt-injection-protection
- content-moderation
- type-safe-validation
- webhook-signatures
- observability
- rate-limiting