Telephony providers for voice AI agents: Why full-stack integration matters

Telephony providers for voice AI agents: Why full-stack integration matters

The voice AI agent market is exploding, but there's a critical infrastructure challenge most providers don't address: telephony. While numerous platforms offer AI conversation capabilities, very few actually own and operate the telephony infrastructure needed to deliver these experiences reliably at scale.

This disconnect matters. When voice AI providers rely on third-party telephony services or carrier partnerships, enterprises face multiple points of failure, increased latency, and fragmented support experiences. The result? Robotic-sounding conversations, compliance gaps, and operational headaches that defeat the purpose of AI automation.

The voice assistant landscape market is projected to be valued at USD 19.09 in 2025, with a forecast to reach USD 81.59 billion by 2032. As this 23.1% compound annual growth rate accelerates, the providers that control their full stack, from carrier infrastructure to AI inference, will define the standard for enterprise deployments.

The telephony gap in voice AI

Most voice AI providers treat telephony as an afterthought—something to be bolted on through APIs or partner integrations. This approach creates fundamental problems:

• Latency compounds when voice data travels through multiple providers and handoffs
• Quality degrades without end-to-end control over the signal path
• Compliance becomes complex when different vendors handle different regulatory requirements
• Troubleshooting turns into finger-pointing between AI providers and telephony partners
• Costs multiply through middlemen markups at each layer of the stack

The enterprises deploying voice AI agents need more than conversation models; they need features like:

• Local numbers and caller ID for better pickup rates and regulatory compliance
• Low-latency infrastructure so conversations don't feel delayed or robotic
• Enterprise-grade compliance features like HIPAA support, STIR/SHAKEN for caller authentication, and GDPR alignment
• Seamless handoff to human agents when a call requires it

Looking for more context? Check out Ozonetel's overview of voice AI agents and MarkTechPost's breakdown of top providers.

Why full-stack ownership changes everything

When a single provider owns every layer, from the physical network to the AI models, enterprises gain:

Ultra-low latency: Processing happens closer to telephony infrastructure with colocated GPUs and edge compute, keeping round-trip time (RTT) under 200ms to power natural conversations.

Predictable quality: No third-party handoffs means consistent call quality and fewer points of failure.

Unified compliance: One provider handling STIR/SHAKEN, HIPAA, GDPR, and other frameworks instead of coordinating between vendors.

Single-pane observability: Call tracing, provisioning, and scaling through one portal instead of multiple dashboards.

True flexibility: Instantly switch between TTS and STT engines, swap LLMs, or bring your own models, all while leveraging enterprise-grade infrastructure. When providers own the full stack, they can integrate new models as they emerge, ensuring you're always using the best available technology without vendor lock-in or complex migrations.

Telnyx: The only true full-stack provider

Telnyx stands alone in owning every layer of the voice AI stack. With carrier licenses in 30+ markets and a global private IP network, Telnyx controls the entire signal path from PSTN to GPU inference. This isn't just vertical integration, it's purpose-built infrastructure designed specifically for AI-powered voice.

Key differentiators include:

• Telephony built for service providers: Direct interconnects with carriers worldwide, not resold minutes
• Colocated compute: GPUs positioned at network edges for minimal latency
• Mission Control Portal: Complete observability, from live call traces to instant scaling
• One-click migration: Seamless transition from platforms like ElevenLabs and Vapi

This combination makes Telnyx the optimal choice for global contact centers, compliance-heavy industries, and builders who need full control. Learn more about how Telnyx approaches voice AI agents here.

How other providers approach telephony

While many platforms offer voice AI capabilities, their telephony integration varies significantly:

CPaaS providers

Twilio
Twilio remains a developer favorite with global numbering and broad APIs. However, Twilio primarily resells carrier services rather than owning infrastructure, adding latency and limiting control over call quality.

Vonage (Nexmo)
Vonage offers strong global coverage, particularly in Europe, but relies on partner networks for telephony delivery, creating potential quality variations across regions.

Cloud platform providers (partner-dependent telephony)

Amazon Connect
Amazon Connect integrates with AWS services like Lex and Contact Lens but depends on third-party carriers for PSTN connectivity. This adds complexity for enterprises needing consistent global coverage.

Google Cloud (Dialogflow + Contact Center AI)
Google offers advanced NLU and ML tooling, but telephony integration varies by region through carrier partnerships. Local number availability and call performance depend heavily on these third-party relationships.

Microsoft Azure Communication Services
Microsoft ACS provides telephony via partner carriers, creating dependencies that can impact latency and numbering breadth based on specific partnerships.

Contact center platforms (hybrid approaches)

Genesys Cloud CX
Genesys uses carrier partnerships for global reach, which works for traditional contact centers but can introduce latency for AI workloads.

8x8
8x8 bundles UCaaS and contact center features but relies on a mix of owned and partner infrastructure, creating inconsistent experiences for voice AI deployments.

RingCentral
RingCentral's telephony footprint varies by region, with quality depending on local carrier relationships.

Zoom Contact Center
Zoom is expanding into AI-enhanced contact center tools (see TechRadar's coverage), but telephony remains dependent on third-party integrations.

The infrastructure requirements for enterprise voice AI

Successful voice AI deployments require more than APIs and models. The underlying telephony infrastructure must deliver:

Reliability: Direct carrier interconnects, redundant routing, and failover capabilities that maintain five-nines uptime.

Global reach with local presence: Carrier licenses and local numbers in target markets, not just SIP trunking through intermediaries.

Edge compute capabilities: Processing power positioned close to the PSTN to minimize latency to ideally under 200ms round-trip.

Compliance-first architecture: Built-in support for STIR/SHAKEN, HIPAA, GDPR, and regional regulations without bolt-on solutions.

Developer-friendly tools: APIs that abstract complexity while providing granular control when needed.

Making the right choice for your organization

Selecting a telephony provider for voice AI isn't about feature comparisons, it's about fundamental architecture decisions:

• Traffic patterns: Global deployments need providers with actual carrier infrastructure, not API aggregators
• Compliance requirements: Healthcare, finance, and regulated industries require end-to-end control for audit trails
• Performance standards: Sub-200ms round-trip time demands colocated compute and direct PSTN access
• Operational complexity: Multiple vendor relationships multiply points of failure and support overhead

Conclusion

Voice AI agents depend on telephony infrastructure that most providers don't own. While many platforms offer compelling AI capabilities, only Telnyx delivers the full-stack ownership required for enterprise-grade deployments.

As organizations move beyond pilots to production deployments handling millions of minutes, the choice of telephony provider becomes strategic. Full-stack ownership isn't just a technical advantage, it's the foundation for delivering natural, compliant, and reliable AI-powered customer experiences at scale.

For teams evaluating voice AI agents, the question isn't which platform has the best features. It's which provider controls the infrastructure needed to deliver those features reliably, globally, and at the performance standards customers expect.