Sinch unveils Voice Relay to power AI-driven calls

Sinch has launched Voice Relay, a feature in its Enterprise Voice platform that connects text-based AI agents to live phone calls. The product is in early access and launches alongside updates to voice infrastructure, branded calling protection and the company's global network.

Sinch described the release as a step towards wider use of AI agents in telephone-based customer service, amid growing interest in agent-led interactions across customer experience and contact centre operations.

Voice challenges

AI assistants are now common in text channels, but live voice brings different operational issues. Low latency matters in spoken conversations. Telecom network connectivity can be a constraint, and fraud prevention has become more prominent as call volumes and automated activity grow.

Many customer interactions still take place over the phone, particularly when issues are urgent or sensitive. Sectors that often rely on voice include financial services, utilities, travel, retail and public services. Organisations in these areas typically balance fast responses with verification, compliance and customer trust.

Building AI-led voice interactions can be complex for enterprises. Tasks include managing audio streaming, running speech recognition, generating synthetic speech and tuning systems to reduce delays during a call.

Voice Relay connects AI agents built on large language models to live calls, giving developers a simpler interface to integrate an agent with Sinch's voice network.

During a call, the service manages the "conversational loop", including speech recognition, voice synthesis and interruption handling. Sinch said the design lets teams focus on conversation design and business logic rather than telecom integration.

Julia Fraser, Executive Vice President Americas at Sinch, said enterprises want to extend AI into phone interactions because voice remains important for customer engagement.

"Voice remains one of the most powerful channels for customer engagement, and enterprises are increasingly looking to bring AI into those interactions," Fraser said. "Voice Relay allows developers to connect AI agents to the global telephone network quickly and reliably, helping them automate routine calls, reduce wait times and resolve issues faster without having to build and manage complex voice infrastructure themselves."

Model choice

Sinch also highlighted model flexibility for large organisations building customer-facing agents. Enterprises have been cautious about being tied to a single AI provider, particularly when systems handle customer data or brand-sensitive conversations.

Daniel Morris, Chief Product Officer at Sinch, said the company expects customers to use a range of AI models and aims to provide the telecom network connection.

"Enterprises want the freedom to choose the AI models that power their agents," Morris said. "Voice Relay provides the infrastructure that connects those agents to the global voice network, delivering the real-time media, reliability and control required to run AI-powered voice interactions in production."

Network and protection

The Voice Relay launch also includes updates across the Enterprise Voice platform, including "AI-ready voice infrastructure", branded calling protection and expanded global network capabilities.

Branded calling protection has become a focus for telecom and communications platform providers as enterprises contend with spoofing and fraudulent call activity. Businesses also face growing reluctance from customers to answer unknown numbers, reducing the effectiveness of outbound contact strategies.

Sinch did not provide technical specifications or pricing for Voice Relay. It described the release as early access, typically indicating limited availability while the product matures through customer testing.

Agentic conversations

Separately, Sinch recently introduced what it calls agentic conversations: a set of functions to operationalise AI agents across messaging, voice and email. The company expects conversational traffic to increase as customer engagement shifts towards agents and automated workflows.

Sinch said customers are not locked into a single agent model, data layer or ecosystem. Adoption options include using Sinch's AI features, bringing third-party agents, building in-house systems, or integrating through partners. Sinch said it provides orchestration and communications infrastructure through its messaging, voice and email APIs.

The statement reflects a broader pattern in customer communications, where vendors position themselves between AI systems and regulated channels such as telephony and email. The approach aims to support control, auditability and routing across regions and carriers, rather than point deployments within a single channel.

Wendy Johnstone linked voice automation to competitive pressure in sectors where customers still expect quick support by phone.

"In high-stakes industries such as travel, retail and public services, the phone remains a critical channel for urgent support. The ability to deploy fully autonomous AI agents is quickly becoming a competitive advantage."

Sinch said it handles more than 900 billion customer interactions each year for more than 200,000 customers globally, and generated net sales of USD $3 billion in 2025.