Full observability for your Retell voice agents
Connect your Retell agent to Tuner with no code, paste your API key, add your Agent ID, and every call's transcript, latency, and outcome flows in automatically. One quality layer that scales with you across every stack you build on.
Integrate in under two minutes
No SDK, no re-architecting. Paste your Retell key, point Tuner at your agent, and Tuner configures the webhook for you.
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Get your Retell credentials
Copy your Retell API key and Agent ID (it starts with agent_) from the Retell dashboard.
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Add your key in Tuner
Paste your Retell API key under Workspace Settings → API Keys & Integrations and save, before you create the agent.
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Create your agent
Add a new agent in Tuner with Provider: retell and your Assistant ID as the Agent Remote ID.
04
Tuner wires the webhook
Tuner configures the Retell webhook automatically. Already using a webhook? The webhook proxy forwards every call to your existing n8n or Zapier flow too.
Read the retell guide →
One dashboard
Every Retell call, scored automatically
Transcripts, latency, usage, and red flags from every call land in one place, so quiet failures surface before they reach your churn data.
Why you need Tuner
Voice agents fail quietly, and at a scale no team can review by hand. Tuner turns every production call into signal you can debug, alert on, test against, and improve.
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Debug in minutes, not days
When a call goes wrong, see exactly what happened and where — the full transcript, every turn, latency at each step, tool calls, and conversation state. No more guessing from sparse logs.
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Get alerted the moment something breaks
Don’t wait for a customer complaint. Configure your own alerts with multiple triggers and conditions — by red flag, metric threshold, agent, or flow — and get notified the instant quality slips.
03
Test before you ship
Run call simulations and automated checks over SIP before every launch and after every change, scored against the same evals that monitor production — so you catch regressions before your callers do.
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Diagnose your agent at scale
At thousands of calls a day, manual validation is impossible. Tuner finds the patterns, pinpoints where your agent breaks, and suggests how to fix it — so one engineer can stay on top of production.
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Analytics that explain production
Understand how your agent actually behaves live: where it breaks, when callers get frustrated, which flows are missing, when it hallucinates, and which tool calls fail the most.
Everything you need to run Retell agents in production
Turn production from a black box into something you can actually monitor, measure, and improve.
Catch failures early
Hallucinations, broken flows, dead air, early hangups, and missed intents are flagged automatically — before they reach your churn data.
Outcome & intent scoring
Score every call against your own outcomes and evals ,not just Retell's call status so you know whether the agent actually did its job.
Real-time alerts
Get notified the moment red flags or failed evals appear in production, instead of weeks later buried in logs.
Call simulation
Stress-test your agent over SIP before launch and after every change, scored against the same evals that monitor live traffic.
Cost, latency & usage per call
Track LLM, TTS, and STT spend and latency on every session, with agent-version tagging so you can compare deploys side by side.
Keep your existing webhooks
Tuner's webhook proxy takes Retell's single webhook slot and forwards the full payload to your original URL, so your automations keep running.
Ship with confidence
Catch regressions the moment a new version ships
Compare agent versions across success rate, red-flag rate, and cost per call, and see exactly which failure types are driving the drop.
Tuner vs Retell's built-in monitoring
Retell's evals bill at ~+$0.10/min—costs climb with call length and scale. Tuner charges per call regardless of length, adds pre-launch SIP simulation with AI agents, and stays independent: not the vendor grading its own agent
Vendor-independent observability, eliminating the conflict of a platform evaluating its own output
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Evals pricing built for scale: tuner price per call, no per minute surcharge
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Per-node breakdown ,pinpoint the exact STT, LLM or TTS step at fault (Vapi only totals each turn)
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SIP call simulations with AI agents, using your live evals
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Root-cause diagnosis with a specific fix, not just metrics
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30+ voice quality metrics & red flags out of the box
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Production monitoring & real-time alerting
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Native call transcripts
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Frequently asked questions
Do I need to write code to connect Vapi to Tuner?
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Does Tuner work with transient (inline) Vapi agents?
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What gets captured?
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Will connecting Tuner break my existing Vapi webhook?
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How long does setup take?
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Does Tuner support alerts and monitoring?
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Can I define my own evaluations and metrics?
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How is Tuner priced?
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Is my call data private and secure?
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