When large language models evolve, one of the biggest risks is regression: new model behavior that breaks something that previously worked. That’s why teams rely on replay testing: rerunning real user interactions from production against the latest model version to ensure nothing critical changes for the worse.
Cekura makes this process simple, automated, and measurable.
What Replay Testing Does
| Function | What It Means |
|---|---|
| Production Data Capture | Cekura automatically logs real user-facing calls or chats from live environments. Sensitive information can be filtered or anonymized. |
| Replay Engine | Feed those stored conversations back into a new model version - such as moving from GPT-4o to GPT-5 in a controlled environment to reproduce realistic behavior. |
| Diffing & Evaluation | Cekura compares new vs. old outputs using numeric, Boolean, or rating-based metrics like accuracy, tone, latency, or hallucination rate, with timestamped issue markers. |
| Human-in-the-Loop Review | Teams can annotate and rank results directly on Cekura’s UI to validate which version performs better in real-world conditions. |
| Regression Detection | Automatically flag drops in correctness, responsiveness, or reliability when migrating to a new model or infrastructure. |
| Batch & Segment Testing | Run replays across user segments, prompt clusters, or domains to identify where performance differs most. |
How Cekura Extends Replay Testing
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Baseline Regression Suites: Teams create steady-state test suites that serve as a “version control” for conversational quality. Cekura re-runs these automatically whenever a prompt, model, or infra change happens in CI/CD.
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Turn-Level Metrics & Charts: Latency, interruptions, and factual correctness are tracked turn by turn, not just at call level, with visual diffs and performance curves.
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Multi-Model Benchmarking: Test GPT-4o vs. GPT-5 vs. Gemini on the same data to quantify which one performs best before deploying to production.
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API & GitHub Integration: The entire platform is accessible by API so you can trigger replays directly from your CI pipeline.
Why It Matters
Without automated replays, teams face blind spots when upgrading models. Cekura closes that gap by showing exactly how a new version behaves on your real users’ conversations, not just synthetic benchmarks.
From regression detection to A/B model comparison, Cekura turns model upgrades into a data-driven decision rather than a leap of faith.