Real agents need more than single-turn evals.
Multi-turn, multi-tool, open source. Yours to extend.
Humanloop scores single input/output pairs through a closed platform. LangWatch is OpenTelemetry-native, simulates full multi-turn agent flows, and gives you the source code under Apache 2.0.
Join thousands of AI developers shipping reliable agents with LangWatch.
How LangWatch compares to Humanloop.
Five things teams care about when picking a quality layer for agents. Each row shows what Humanloop ships today and what LangWatch gives you on day one.
Simulate multi-turn, multi-modal conversations with tool use, persistent state, and a configurable virtual user.
Traditional eval platform focused on single input/output pairs. Multi-step agent flows are not the core model.
Transparent codebase. Self-host with Docker or Helm. Customize anything. Audit every component.
Closed-source platform with restricted customization and dependency on vendor-controlled infrastructure.
Standardized tracing, metrics, and logging across every supported framework, no extra configuration.
Proprietary SDK integration required, limiting interoperability with existing observability tooling.
Python and TypeScript APIs for complex logic. UI for domain experts. Both edit the same source of truth.
Platform-centric workflows designed primarily for manual testing and GUI-based configuration.
Real optimization algorithms that generate, score, and select prompt variants automatically.
Prompt versioning and A/B testing capabilities, but optimization decisions still require human intervention.
Three reasons agent teams choose LangWatch.
Multi-turn simulations exercise tools, state, and reasoning. The kinds of failures that pop in production show up here first.
Self-hosted Apache 2.0 deployment removes platform discontinuation risk. Acquisition-proof, by design.
Algorithmic prompt optimization through systematic experimentation. Stop tuning prompts by hand.
“Single-turn evals shipped a polite agent that broke on call three. Multi-turn simulations caught it in seven minutes.”
Evals are table stakes. Agent simulation is the bar.
Try LangWatch yourself or book time with an expert to help you get set up.