Built for LLMs. Not retrofitted from ML monitoring.

Statistical drift was the old story. Agent behaviour is the new one.

Arize started in classic ML monitoring and bolted on LLM features. LangWatch is LLM-native end to end: scenario simulation, conversation-aware evals, prompt optimization, and a workflow domain experts can run.

Join thousands of AI developers shipping reliable agents with LangWatch.

ML-monitor view
statistical drift
kl-div ↑ 0.18 · what now?
LLM-native view
agent conversation
user: refund unused minutes?
agent: lookup_account()
judge: policy-violation
caught at turn-03 · pre-prod
from drift to dialogueLLM-native
The Arize alternative.

How LangWatch compares to Arize.

Five things teams care about when picking a quality layer for agents. Each row shows what Arize ships today and what LangWatch gives you on day one.

01
Pre-production testing
Agent simulation suite

Scenario-based testing simulates real users against your full agent stack with tools, state, and a judge.

Input/output evaluation

Traditional evaluation on input/output pairs with statistical analysis. Limited for multi-turn agent behaviour.

02
Platform origin
LLM-native architecture

Purpose-built for conversation flows, prompt engineering, and agent-specific evaluation patterns.

ML monitoring, LLM bolted on

Drift detection and statistical analysis remain the spine. LLM features are extensions of that worldview.

03
Who can use it
Engineers + domain experts

Friendly platform UI for domain experts. Powerful APIs and SDKs for engineers building complex workflows.

ML engineers, data scientists

Advanced statistical tools designed for technical teams. Steep ramp for product or business users.

04
Prompt optimization
DSPy-native automation

Systematic generation and scoring of prompt variants using real optimization algorithms.

Manual prompt management

Standard prompt versioning and tracking. Optimization happens by hand, run after run.

05
Evaluation library
LLM-as-judge + bring-your-own

Full library of LLM and agent-specific evaluators, plus a one-line API to attach your own metrics to traces.

Statistical evals

Strong on statistical evals and drift, lighter on conversation-level quality and agent-specific scoring.

Three reasons agent teams choose LangWatch.

scenario.run() · 240 simsedge case found · turn-08
Simulate real users

Scenario-based testing finds workflow failures and edge cases during development, before production sees them.

conversation tracesprompt registryagent-aware evalsDSPy optimization
LLM-native, end to end

Conversation traces, prompt registry, agent-aware evaluators, and DSPy optimization in one platform.

scenarios.tsscenario.run()// engineersscenario UIdomain experts
Hybrid collaboration

Domain experts create test scenarios in the UI. Engineers implement advanced evaluation logic in code.

Drift charts told us something changed. Scenario tests told us what would break. We finally had agent-level quality, not ML metrics.
Director of AI · Search and recommendation platform
94%
regressions caught pre-prod
5 min
time-to-first-eval
any
frameworks supported
$0
cost to start

Move from ML monitoring to agent quality.

Connect in five minutes. Any framework, any model. Agent simulation included on day one.