Voice agents should be load-tested before they go live, according to AssemblyAI, which has laid out three specific areas teams need to probe: worst-case telephony audio, peak concurrency, and billable session handling. The guidance amounts to a pre-launch checklist for companies deploying voice AI, a category where failures tend to surface in production rather than in the lab.
Why telephony audio breaks voice agents
Voice agents don't operate in clean audio. Real phone lines introduce background noise, compression artifacts, packet loss, and clipped speech — conditions that rarely show up in a developer's test environment. AssemblyAI recommends testing against the worst telephony audio conditions a deployment is likely to encounter, not the average. A model that transcribes studio-quality recordings perfectly can still mishear a customer calling from a moving car or a crowded room. The point isn't to prove the agent works under ideal conditions. It's to find where it stops working before a caller does.
Peak concurrency is the test most teams skip
Load testing at peak concurrency means simulating the maximum number of simultaneous calls the system is expected to handle — and then some. Voice agents are stateful, real-time systems, and the failure modes under load are different from those of a typical web API. Latency creeps up. Turn-taking breaks down. Calls that worked fine in isolation start dropping mid-sentence. AssemblyAI's recommendation is to run these tests before launch rather than discovering the ceiling when traffic spikes. For teams that have only tested single sessions or small batches, the peak-concurrency test is often the first time the system's actual limits become visible.
Billable session handling needs a pre-launch audit
The third area is billing. Voice agents that connect to telephony providers or usage-based platforms generate billable sessions, and session handling bugs can create charges that don't match actual usage — or fail to record sessions that should be billed. AssemblyAI recommends testing billable session handling before launch, which means verifying that sessions start, stop, and reconcile correctly under the same conditions the agent will face in production. This isn't just a finance concern. Mismatched session records can also make it harder to diagnose dropped calls or failed interactions later.
What the guidance means for launch timelines
None of the three tests is exotic. The problem is sequencing. Teams under launch pressure tend to validate the conversational flow first and defer load and billing tests until after a soft launch. AssemblyAI's guidance pushes the opposite order: stress the audio, stress the concurrency, audit the session handling, then ship. For companies already in production, the same tests can be run as a retroactive audit, though the cost of finding a concurrency ceiling after launch is usually higher than finding it before.
AssemblyAI hasn't attached a timeline or a certification program to the recommendations. They're presented as pre-launch practices, not a compliance standard. Teams building on the platform will have to decide how much of the checklist to adopt before their next release — and whether their current test harness can simulate the telephony conditions the guidance describes.
