Grok Voice API Empowers Real‐Time Voice Agents

December 23, 2025

🔊 Soundcheck

  • Voice‑first AI dev toolkit unleashed

  • Hyro raises $45M to revolutionize voice AI in healthcare

  • Enterprise AI agents just got real big.

Read time: 4 minutes

🔥 Hot Mic

Big moves, deep dives, and standout stories.

xAI released the Grok Voice Agent API, offering fast, multilingual, tool‑calling voice agents at just $0.05/min.

xAI has unveiled the Grok Voice Agent API, making its powerful voice‑agent technology widely available. It harnesses the same engine used in Tesla vehicles and mobile apps, bringing proven, real‑time voice capabilities into developers’ hands. The API supports dozens of languages and excels in pronunciation, accent, and prosody, with automatic language detection and seamless language switching. It delivers outstanding performance—ranking first in audio reasoning benchmarks and boasting sub‑second response time—while remaining cost‑efficient at a flat rate of $0.05 per minute. Developers can also integrate real‑time web or X search, custom tools, and pick expressive voices like Ara, Eve, Leo, or Rex to craft tailored conversational experiences.

Key Points:

  • Built on Grok Voice tech used in Tesla and mobile apps

  • Achieves under‑1‑second response latency—#1 in audio benchmarks

  • Flat $0.05 per minute billing, undercutting typical token pricing

  • Supports auto language detection and seamless multilingual switching

Takeaway: With its speed, affordability, multilingual skill, and tool‑calling flexibility, the Grok Voice Agent API dramatically lowers the barrier for developers to build rich, conversational AI experiences.

Hyro secured $45 million in growth funding to expand its voice AI agents across healthcare systems.

Hyro, a startup born from Cornell Tech’s Startup Studio, just raised $45 million in a growth round led by strategic healthcare investors and VCs. The funding follows just 10 months after its previous round and brings total capital raised to $95 million. Hyro’s voice and chat AI agents help patients with scheduling, prescriptions, and billing—while seamlessly handing off to human support when needed.

Founded by Israel Krush and Rom Cohen in 2018, Hyro has scaled fast, now serving more than 45 major health systems and tens of millions of patients. The new capital will fuel expansion into specialty care AI agents and proactive outreach tools, such as screening reminders and bi-directional patient engagement, improving both access and efficiency in healthcare.

Key Points:

  • Raised $45 million growth round, bringing total to $95 million

  • Funding led by Healthier Capital, with Norwest, Define Ventures, others

  • Platform serves over 45 health systems and 30 million patients

  • Building specialty care agents and proactive patient outreach tools

Takeaway: This latest round underscores growing demand for healthcare-specific voice AI—Hyro’s domain-focused agents are gaining trust by integrating deeply into workflows and expanding into proactive patient outreach to drive efficiency and access.

Sierra AI's $10B valuation and $100M ARR mark enterprise-grade conversational AI stepping into indispensable infrastructure.

Sierra AI’s explosive valuation jump reflects the shift from speculative chatbot hype to practical, mission‑critical agent deployment. Founded by Bret Taylor and Clay Bavor, the startup quickly scaled to $100M in ARR, proving enterprise trust in AI agents is not just talk.

The company’s Agent OS and Data Platform support memory‑infused, context‑aware agents across regulated workflows. This isn't just about chat—it’s about AI that acts reliably, governance baked in, and agents embedded deeply into operations. The question now is whether Sierra can sustain this growth amid rising expectations and stiff competition.

Key Points:

  • Raised $350M in September 2025 at a $10 billion valuation.

  • Reached $100M annual recurring revenue within seven quarters.

  • Agent OS 2.0 and Data Platform enable memory-driven, governed AI workflows.

  • High-touch enterprise adoption across fintech, healthcare, retail, and more.

Takeaway: Sierra’s leap to a $10B valuation alongside rapid ARR growth demonstrates that conversational AI is maturing into foundational enterprise infrastructure—no longer experimental, but essential. The real test now is delivering consistent ROI and trust at scale.

🎙️ Mic Drop

What else is making noise in voice AI.

Minuscule introduces Agentforce Voice capabilities for Salesforce, promising improved AI-powered voice support in contact centers. (aithority.com)

Together AI releases new TTS models for partners, expanding multi-cloud voice service options for developers. (gamesbeat.com)

VoAgents upgrades its platform with capabilities to automate both inbound and outbound calls at enterprise scale. (openpr.com)

Concentrix debuts emotionally aware conversational AI, elevating customer engagement through empathetic automation for brands. (quiverquant.com)

Concentrix unveils pre-built conversational AI agents to streamline deployment for enterprise clients. (verdict.co.uk)

Explores deploying private, local voice assistants for smart homes as privacy-focused alternatives to mainstream platforms. (restechtoday.com)

Wasatch streamlines leasing for multifamily properties using AI voice agents to boost prospect experience and operational efficiency. (usatoday.xpr-gannett.com)

Examines SoundHound's focus on restaurant voice AI and its impact on sustained company growth. (zacks.com)

Known secures $9.7M in funding, targeting matchmaking and communication with voice-first dating app experiences. (cryptorank.io)

Industry report forecasts massive growth and ROI for conversational AI in healthcare over the next decade. (openpr.com)