Retell makes it easy to build powerful voice agents. The harder part is making sure they behave correctly across thousands of real-world conversations before and after launch.
Cekura helps teams building on Retell move from manual spot checks to automated, measurable quality engineering across the full lifecycle of their voice agents. From simulation to production monitoring, here is how to properly test Retell-powered voice systems at scale.
Native Retell Integration for Voice and Chat
Cekura provides direct integrations with Retell for both voice and chat agents, allowing teams to:
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Automatically trigger inbound and outbound calls
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Run text-based chat tests using Retell chat agents
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Sync call metadata, transcripts, and evaluation results
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Auto-populate provider call IDs for correlation
Retell users can enable outbound auto-calling directly from Agent Settings without manual dialing. Test runs are matched one-to-one with evaluation sessions to avoid timeouts and mislinked calls.
This removes manual copy-paste workflows and supports fully automated CI pipelines for Retell agents.
Test Every Stage of the Voice Agent Lifecycle
Retell agents need validation across multiple stages:
While Building: Component Testing
Validate:
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Slot/entity capture
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Tool calls
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Instruction following
Cekura runs structured simulations against individual flows to confirm each part of the agent behaves as expected.
Before Go-Live: End-to-End Stress Testing
Simulate complete, real-world journeys such as:
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Booking an appointment
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Modifying an order
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Escalating to a human
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Handling hearing issues and repetition
Each scenario is paired with expected outcomes and evaluated automatically.
Teams can also run A/B comparisons between two Retell agent versions using identical evaluator sets to measure regressions before deployment.
Post Go-Live: Production Monitoring
Instead of manually reviewing recordings, Cekura evaluates live production calls via observability APIs.
Imported Retell calls can be evaluated at:
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0.2 credits per metric run
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Voice tests consume 5 credits per minute
This makes high-volume monitoring economically predictable.
Metric-wise alerts via Slack or email notify teams when quality drifts, including trend-based anomaly detection.
Deep Conversational Metrics for Retell Voice Agents
Cekura measures over 25 predefined metrics across four core layers
Cekura measures over 25 predefined metrics across four core layers:
Speech Quality
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Words per minute
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Talk ratio
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Average pitch
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Voice tone and clarity
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Letterwise pronunciation detection
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Pronunciation checks
The Voice Tone + Clarity metric evaluates audio directly and costs 0.2 credits per minute processed.
Conversational Flow
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Latency
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AI interrupting user
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User interrupting AI
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Interruption overrun time
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Silence detection
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Appropriate call termination
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Unnecessary repetition count
Lindy used interruption testing to reduce stop time after user interruption to under one second in many cases, ensuring the agent never talks over the customer.
They also maintain under 200 WPM and talk ratio below 0.8 to preserve natural cadence.
AI Accuracy
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Instruction follow
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Relevancy
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Response consistency
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Hallucination detection
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Tool call success
Tool call verification confirms actions like:
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Updating a CRM
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Editing an order
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Validating account balance
Customer Experience
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CSAT scoring
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Sentiment analysis
These metrics provide measurable indicators of conversational quality beyond surface-level transcript checks.
Personalities and Real-World Simulation
Real users interrupt, mumble, switch topics, and challenge agents.
Cekura includes 50+ predefined personalities including:
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Interrupter
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Pauser
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Accent-based personas
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Broken English speakers
Teams can override personalities at runtime to test bias and behavioral drift without modifying evaluators.
If you run 10 scenarios across 3 personalities, Cekura automatically executes 30 calls and compiles the results.
Red Teaming for Compliance and Security
Retell agents operating in BFSI, healthcare, or legal environments must withstand adversarial behavior.
Cekura Red Teaming includes:
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10,000+ multi-turn adversarial scenarios
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Jailbreak simulations
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Bias testing
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Toxicity provocation
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PII and data leakage extraction attempts
Enterprise teams can also engage our Forward Deployed Engineers to build custom adversarial test libraries tailored to HIPAA, PCI DSS, or other sector-specific requirements.
Regression Testing and CI/CD for Retell Agents
Prompt updates often break unrelated flows.
Cekura supports:
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Scheduled Cron-based test runs
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Pre-built CI infrastructure test suites
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Parallel call throttling to manage concurrency
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Up to 2000+ concurrent call load testing
Twin Health runs full regression simulations before every deployment to ensure that prompt tweaks do not break clinical workflows.
Infrastructure and Telephony Flexibility
Retell agents can be tested across:
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PSTN
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SIP
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WebRTC
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Bring Your Own Telephony via Twilio or Telnyx
Cekura also supports:
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IVR simulation with DTMF
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Voicemail testing
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OTP and SMS validation during calls
This ensures complete flow validation beyond simple speech exchange.
Enterprise Security and Compliance
Cekura supports enterprise deployments with:
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SOC 2 Type II
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HIPAA readiness
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GDPR compliance
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Role-based access control
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VPC deployment options
Healthcare teams can request a BAA and securely evaluate calls containing PHI. Plus, sensitive transcripts and audio can be automatically redacted during observability ingestion.
Pricing Built for Scaling Retell QA
Developer Plan:
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$30 per month
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750 credits included
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10 concurrent calls
Enterprise Plan:
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Custom concurrency
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Custom credits
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Dedicated support
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Custom integrations and red teaming as a service
Voice testing: 5 credits per minute. Evaluation: 0.2 credits per metric.
This transparent credit model allows teams to estimate cost per call and per deployment gate.
Moving from Manual QA to Measurable Reliability
Teams building on Retell often begin with manual testing; calling the agent repeatedly does not scale.
Lindy transformed QA from a manual bottleneck into a structured quality engineering workflow using Cekura.
Twin Health moved from anecdotal testing to simulation-driven clinical validation across thousands of conversational paths.
For teams building voice agents on Retell, automated testing and continuous observability are the difference between experimental demos and production-grade systems.
Cekura provides the infrastructure to simulate, measure, secure, and continuously improve Retell-powered voice agents at scale.