The scaling challenge voice AI can’t ignore

Every month, my team at Speechmatics processes more than 500 years of human conversation. That includes meetings, customer service calls, medical consultations and voice assistant interactions. 

All of it happens in real time and depends on systems that can handle pressure without breaking.

To make this work, speed and accuracy matter. But the foundation holding everything up is something else entirely: concurrency.

Concurrency means handling many live speech sessions at the same time, with each one starting immediately and continuing smoothly, often for hours. 

It is the difference between a demo that runs smoothly and a product that delivers at scale. Without concurrency, even high-performance models can fall short when demand grows.

What real-time voice actually looks like

A lot of people think of voice input as short, disconnected moments, like clicking a button or typing a quick query. But real-time speech is different. It involves continuous audio streams that stay active. 

Video calls, live transcriptions and voice interfaces all rely on systems that can process audio without interruption from the moment the session begins.

Our real-time platform supports sessions up to 48 hours. In some cases, we’ve hosted conversations that lasted more than 100 days. 

Supporting that kind of persistence means building for long-haul performance, not just speed.

What happens when systems can't keep up

Startups often run into problems when their concurrency limits are tested. A platform might perform well in testing and even handle a few early customer pilots. But things change fast when a major client joins, whether it’s a contact center with hundreds of agents or a healthcare provider running dozens of remote consultations at once.

At that point, new sessions take too long to connect. Audio starts cutting out. Reliability drops. The issues tend to surface at exactly the wrong moment, when expectations are highest and performance matters most.

Healthcare use cases show this clearly. Consultations spike at certain times of day and during seasonal peaks. These are not minor fluctuations, they require real, flexible capacity. 

A system that performs well with 50 sessions may completely fail at 500.

What we do differently

At Speechmatics, we design our systems around real-time speech from the start. We plan for concurrency as a core requirement, not an add-on. That means everything from session state management to load distribution is architected to handle live audio under pressure.

This level of performance also relies on operations. Engineering matters, but so does the ability to monitor, manage and respond in milliseconds. Voice workloads place unique demands on systems, and they require teams who treat uptime and latency as fundamental measures of success.

We also don’t rely on brute force or shortcuts. We invest in structure that can scale without compromise — able to coordinate speech recognition, customer logic and real-time response even during peak usage.

Why it matters early

The platform you choose early on sets the limits of your growth. A speech system that struggles with concurrency creates problems long before you hit scale. And the fixes aren’t simple. Teams often spend months trying to patch systems that were never built to handle live sessions at volume.

Concurrency needs to be part of your technical plan from day one. If it’s not, every future milestone gets harder. Reliability falters. New features take longer to launch. And engineering velocity slows just when momentum should be building.

Where this is going

Voice AI is evolving fast. New products are already combining transcription, text-to-speech and large language models in the same flow. Making those experiences feel smooth requires infrastructure that can coordinate them in real time, at scale, without gaps.

At Speechmatics, we’re building for that future. Our systems support on-prem deployments, can absorb spikes in demand and are designed to keep multiple AI models working together in sync.

The companies that succeed in voice will be those who build for concurrency upfront, not because it’s a nice-to-have, but because everything else depends on it.