Hevo

Test voice agents before your customers do.

Simulate conversations, score every call, and trace latency turn by turn. One platform from staging to production.

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Call analysis view with audio waveform, turn-by-turn trace timeline, and synchronized transcript

Works with your voice stack

Point your provider at Hevo and calls start flowing in. No changes to your agent code.

VAPIAvailable

Sync production calls, recordings, and transcripts.

Retell AIAvailable

Import calls with word-level transcript timing.

Bland AIOn request

Connect through a webhook. Ask us to enable it.

Voice breaks in ways dashboards miss

Your agent took an action on a live phone call with a real customer. By the time a complaint reaches you, the call is over and the context is gone.

A bad turn ends the call

Text users retry. Phone callers hang up, and you never learn why.

Latency is cumulative

Speech recognition, model, and speech synthesis each add delay to every single turn.

Logs are not conversations

Reading a transcript tells you what was said, not how it sounded or where it stalled.

One loop: simulate, evaluate, monitor

Catch regressions in staging, grade what ships, and keep watching once real callers arrive.

Simulate

Run the call before it happens

Drive scripted personas through your agent and replay the same scenario after every prompt change.

  • Reusable scenarios per agent
  • Repeatable runs against any provider
  • Compare results across versions
Stage progression funnel showing where callers drop off between greeting, discovery, and closing
Evaluate

Score conversations automatically

Every call is graded on resolution, sentiment, turn efficiency, and conversion, so you can rank the worst calls first.

  • Automated quality scoring
  • Top failing checks surfaced first
  • Worst calls queued for review
Quality insights view listing top problems to fix and quality scores trending over time
Monitor

Watch production in real time

Call volume, handle time, cost composition, and latency breakdown across speech recognition, model, and synthesis.

  • Cost split by model and telephony
  • Latency broken out per stage
  • Sentiment trends by hour
Operations dashboard showing call volume, average handle time, spend, and latency breakdown

Built for debugging real calls

Open any conversation and see exactly what the agent heard, decided, said, and spent.

Turn-by-turn traces

Inspect any turn down to the model used, tokens spent, tools called, and the latency contributed by each stage.

Turn inspector showing processing pipeline, model, token count, and latency waterfall

Cost per call, not per month

Spend is split across the model, speech recognition, speech synthesis, and telephony, for every single call.

Model
tokens in and out
Speech to text
billed duration
Text to speech
characters spoken
Telephony
provider minutes

Audio beside the transcript

Scrub the recording and the transcript follows. Hear the pause your users complained about instead of guessing at it from logs.

Volume and outcomes over time

Track resolution, conversion, and drop-off week over week so prompt changes show up as numbers, not opinions.

Call metrics dashboard with weekly call volume, resolution rate, conversion rate, and drop-off rate

Connected in an afternoon

No SDK to install and no changes to your agent logic.

  1. 1

    Connect your provider

    Add your provider API key in the dashboard and point its webhook at your workspace endpoint.

  2. 2

    Calls arrive on their own

    Recordings, transcripts, traces, and cost land in your workspace as each call ends.

  3. 3

    Review and get alerted

    Scores run automatically. Failures and degraded metrics raise a notification.

connect-vapi.sh
# Point your provider webhook at your workspace
curl -X PATCH https://api.vapi.ai/assistant/$ASSISTANT_ID \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "serverUrl": "https://app.hevo.dev/api/webhooks/vapi",
    "serverMessages": ["end-of-call-report", "status-update"]
  }'

Straight answers on security

Call recordings are sensitive. Here is what is in place today, and what is not yet.

Encrypted provider credentials

Provider and model API keys are encrypted with AES-256-GCM before they are stored.

Bring your own model keys

Run evaluations against your own model accounts so inference stays on your billing and your terms.

Workspace isolation

Calls, agents, and evaluation runs are scoped to a workspace, with roles controlling access.

Your data stays yours

We do not train models on your calls, transcripts, or recordings.

Not available yet

SSO and SAML, SOC 2 Type II, Configurable data retention. If one of these blocks a rollout for your team, get in touch and we will share timelines.

Questions buyers ask

See it against your own calls

Bring a provider key and a handful of recent calls. We will walk through what the traces and scores show.

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