Sub-500ms voice AI latency — because callers notice every half second

Vociply delivers end-to-end voice AI response times under 500ms in production. Not in demos. Not in controlled benchmarks. In live calls, at scale, globally.

Human conversational turn-taking averages 200–300ms. Above 700ms, callers perceive a pause and start speaking again.

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< 500ms latency|99.99% uptime|SOC2 + HIPAA

The problem you already know

High latency is the fastest way to destroy the illusion of a natural conversation. When an AI agent takes 1.5 seconds to respond after a caller finishes speaking, callers either assume the line dropped or start talking again — creating crosstalk that cascades into a broken interaction. Most voice AI platforms quote "first token" latency, which measures only the first word of the AI response, not the complete utterance. In a real conversation, a response like "Sure, let me look that up for you" has multiple tokens — what matters is how quickly the full, speakable response is delivered to the caller's ear. Vociply measures end-to-end latency: from the moment the caller finishes speaking to the moment the caller hears the first syllable of the response. This is the number that determines whether a call sounds like talking to a person or a robot. Our median is under 500ms. Our 95th percentile stays under 750ms globally.

What teams build with Vociply

Real-time conversation — not chatbot cadence

At sub-500ms response time, AI voice conversations feel natural to callers. Responses arrive before the conversational silence becomes awkward. Callers stop noticing the technology and focus on the outcome.

High-frequency transactional calls

Order status, balance inquiries, appointment confirmations — calls where callers want fast answers. Sub-500ms latency makes these interactions 40–60% shorter, improving throughput and reducing cost-per-call.

Complex multi-turn conversations

Sales qualification, insurance FNOL, and support troubleshooting involve many turns. Low latency prevents the compounding effect where each delay degrades caller patience further. Calls complete, not abandon.

Global enterprise deployments

Vociply routes traffic through regional infrastructure to minimize geographic latency. Deployments in North America, Europe, and Asia-Pacific maintain sub-500ms medians regardless of caller location.

High-volume contact centers

At 100,000 calls per day, the performance envelope must hold. Vociply's architecture maintains latency targets under load — not just in isolated tests. Concurrent call capacity scales without latency degradation.

Latency-sensitive verticals

Healthcare triage, fraud alert calls, and emergency dispatch lines — where caller anxiety is already elevated and hesitation reads as incompetence. Sub-500ms response times signal capability and control.

Under the hood

How Vociply achieves sub-500ms latency

End-to-end latency in voice AI has three components: speech-to-text (STT), language model inference, and text-to-speech (TTS). Vociply runs optimized versions of each stage in a streaming pipeline — STT results stream to the LLM as the caller speaks; LLM tokens stream to TTS before the full response is generated; TTS audio streams to the caller as tokens arrive. Each stage is overlapped with the next, eliminating sequential wait times. We colocate all three components in the same infrastructure region as your telephony endpoint.

How we measure and report latency

Vociply measures Time-To-First-Audio (TTFA): the interval between end-of-utterance detection (when the caller stops speaking) and the first audio byte delivered to the telephony stream. We track median, p95, and p99 latency continuously across all active calls. These metrics are available in the platform dashboard and via API for SLA monitoring. We publish benchmarks quarterly against independent recordings.

Latency under production load

Benchmark latency in a demo environment is meaningless without production validation. Vociply's infrastructure is capacity-provisioned to maintain latency targets at 10x current peak load. Auto-scaling ensures no single traffic spike degrades response times. Our SLA for enterprise customers guarantees p95 TTFA ≤ 750ms — backed by service credits.

How Vociply compares

FeatureVociplyVapiRetell AI
Median TTFA (production)< 500ms600–900ms (reported)500–700ms (reported)
p95 TTFA< 750ms1,200–1,800ms900–1,200ms
Latency measurement definitionEnd-to-end TTFA (full utterance)First token (partial)First token (partial)
Geographic coverageUS, EU, APACUS primaryUS primary
Latency SLAp95 ≤ 750ms, service creditsNoneNone
Latency under peak load10x provisioned, guaranteedDegrades at scaleDegrades at scale
Streaming pipelineFully overlapped STT → LLM → TTSSequentialPartial streaming
Dashboard visibilityReal-time p50/p95/p99 per agentBasic metricsBasic metrics

Get started in 3 steps

1

Create your agent

Sign up, name your agent, choose a voice, and write a system prompt — or pick a pre-built template for support, sales, or scheduling.

2

Connect your tools

Attach a knowledge base (PDF, URL, or website), build a visual workflow, and connect integrations like Google Calendar, Slack, or your CRM.

3

Assign a phone number and go live

Link a Twilio or Telnyx number. Your agent starts answering calls immediately — or launch an outbound campaign with a contact list.

Frequently asked questions

What is "end-to-end" latency vs. "first token" latency?

First token latency measures how quickly the AI produces its first output token — a single word or syllable. End-to-end latency (TTFA) measures from when the caller stops speaking to when they hear the first audio. First token is only one component of TTFA. Vociply reports TTFA because that is the number callers actually experience — and it is consistently lower for us than competitors who quote first-token figures.

Does latency increase at higher call volumes?

No — when properly architected. Vociply's infrastructure auto-scales horizontally. Each call runs in an isolated processing pipeline; latency is not shared across concurrent calls. We provision at 10x measured peak load and maintain latency targets even during unexpected volume spikes. Enterprise SLAs include p95 latency guarantees backed by service credits.

How does caller location affect latency?

Geographic distance between the telephony endpoint and the AI processing infrastructure adds network latency. Vociply operates regional infrastructure in North America, Europe, and Asia-Pacific. Calls are routed to the closest regional endpoint automatically. For enterprise deployments requiring specific data residency, we can configure dedicated regional routing.

What is the typical caller experience at 500ms vs. 1,000ms?

At 500ms, the response arrives within the natural pause of conversation — callers do not notice a delay. At 700–800ms, attentive callers perceive a slight pause but the conversation flows. Above 1,000ms, callers consistently notice the gap and often start speaking again, creating crosstalk. Above 1,500ms, abandonment rates on simple calls increase measurably. Latency directly impacts CSAT and first-call resolution.

Can we monitor latency in real time?

Yes. The Vociply dashboard shows real-time and historical latency metrics per agent, per campaign, and platform-wide. You can set latency alerts and export metrics to your observability stack via webhook. Enterprise customers can access raw latency data via API for integration with Datadog, Grafana, or custom monitoring.

Ready to move past a POC?

Book a 30-minute technical demo with a solutions engineer. No slides — we build your first agent live.