Prevalpreval
Observe·Evaluate·Simulate

preval your agents before your users do.

Simulate conversations before launch, trace every LLM call and voice span in production, and auto-score every response — so nothing slips through, from first test to millionth call.

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Global observability

Monitor agents across every region. Trace LLM calls, voice pipelines, and tool executions from users worldwide — with <5ms overhead. Evaluate quality automatically, catch regressions before they reach production.

Everything you need to ship
reliable AI agents.

From first trace to production monitoring — Preval covers the full AI agent lifecycle.

01

Real-time tracing

Every LLM call, STT transcription, TTS synthesis, and tool execution captured as spans with latency, tokens, and cost.

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02

Automated evaluations

18+ LLM-as-judge metrics score every trace automatically — task completion, hallucination, sentiment, accuracy.

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03

Unified playground

Compare models A/B/C side-by-side. Run datasets, stream outputs, and score results with built-in evaluators.

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04

PII detection

Microsoft Presidio-powered scanning detects 50+ entity types. Flag sensitive data in traces before it reaches production.

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05

Prompt optimization

AI-powered prompt improvement loop. Test, evaluate, improve, ship. Get better prompts with every iteration.

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06

SDK in 3 lines

pip install preval. Three lines instruments OpenAI, LangChain, CrewAI, LiveKit, or any OpenTelemetry app.

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3-line integration

No complex setup.
Just trace.

Install the SDK, add three lines, and every LLM call, tool execution, and voice span is automatically captured with latency, tokens, and cost.

GuidesGuidesSDK DocsSDK Docs
1import preval
2
3# Initialize in 3 lines
4p = preval.init(
5 api_key="prz_your_key",
6 project="my-voice-agent"
7)
8
9# Auto-instrument all LLM calls
10p.init_opentelemetry()
11
12# That's it — every OpenAI, Anthropic,
13# Google call is now traced automatically

Works with every major AI provider and framework

OpenAIOpenAI
AnthropicAnthropic
GoogleGoogle
MetaMeta
DeepSeekDeepSeek
Pricing

Start free.
Scale when ready.

Preval supports Bring Your Own Keys.

Free

$0forever

For individual developers exploring AI agent observability

  • +10K traces/month
  • +7-day retention
  • +1 project
  • +4 preset evaluators
  • +Community support
  • +SDK + OTLP ingestion
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Ship

$29/month

For teams shipping AI agents to production

  • +500K traces/month
  • +30-day retention
  • +5 projects
  • +Custom evaluators
  • +Unified Playground
  • +Priority support
  • +CSV export
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Scale

$79/month

For teams running AI agents at scale

  • +5M traces/month
  • +90-day retention
  • +Unlimited projects
  • +Red team testing
  • +Auto-improve
  • +Drift detection
  • +Dedicated support
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