OpenCall: Real-time, low latency AI voice at enterprise scale

"OpenCall.ai powers AI-driven voice interactions at enterprise scale, where every millisecond of latency and every nuance of natural speech directly impacts the end-user experience. Tech 42 helped us take our fine-tuned Sesame CSM text-to-speech model from concept to production on AWS — delivering a dedicated, real-time voice generation layer with streaming audio and word-level alignment that our platform depends on.

The architecture is built for performance and reliability: GPU-backed ECS infrastructure, containerized model deployment via ECR, S3-based model loading, WebSocket audio streaming, CSM-native alignment metadata, API key authentication, and fully Terraform-managed infrastructure — all working together to give our platform precise, real-time visibility into what words are being spoken as audio is produced.

One of the most valuable contributions was Tech 42's approach to intelligent autoscaling — balancing GPU utilization, active Gateway connections, and TTS capacity signals to keep the service responsive without letting idle GPU capacity drive up costs. For a production speech model running at scale, that balance is everything.

Tech 42 also set our team up for long-term ownership with smoke-test scripts, operational documentation, model refresh guidance, API key rotation procedures, and a hands-on knowledge transfer session. Their depth in MLOps, AWS infrastructure, and real-time AI systems made them a true partner in extending our Sesame CSM platform — and the result is a voice experience that is more natural, more scalable, and fully production-ready.

What stood out beyond the technical delivery was the team itself. Tech 42 consistently went above and beyond — proactively solving problems, communicating with clarity, and showing genuine investment in our success. They felt less like a consulting partner and more like an extension of our own team. We look forward to continuing to partner with Tech 42 on future initiatives as we scale our platform."

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