Helicone vs LangWatch
Updated March 27, 2026
Overview
Helicone is an open-source LLM observability and proxy platform. By adding a single line of code, developers get request logging, cost tracking, caching, rate limiting, and analytics for their LLM applications. Helicone supports all major LLM providers and offers both proxy and async logging modes. Popular with startups for its generous free tier and simple integration.
Open-source LLMOps platform for testing, evaluating, and monitoring AI agents. Differentiated by multi-turn agent simulation testing.
Key features
Core capabilities each platform advertises.
- Multi-turn agent simulation testing
- LLM evaluation with custom evaluators
- OpenTelemetry-native tracing
- Prompt & model management
- Dataset management from production traces
Strengths and tradeoffs
What each tool does well, and the limitations to keep in mind.
Pros
- Open-source with 5.2K GitHub stars and strong community support
- Minimal latency overhead (under 1ms for self-hosted)
- Flexible deployment options including cloud-hosted, self-hosted, or SDK-only
- Y Combinator-backed with SOC 2 Type II and HIPAA compliance
- No code changes required for AI Gateway features like caching and rate limiting
Cons
- Adds computational cost and one network hop for cloud deployment
- Limited pricing transparency on website
- May require infrastructure expertise for self-hosted setup
Pros
- Unique agent simulation testing via Scenario framework — enables multi-turn, stateful agent testing unmatched by LangSmith or Langfuse
- Fully open-source with MIT license and no feature gating on self-hosted deployments
- All-in-one platform combining tracing, evaluation, prompt management, and PII redaction
- Framework-agnostic with OpenTelemetry-native integration across all major agent frameworks
- Enterprise-ready with ISO 27001, SOC2, GDPR compliance, and on-prem deployment options
Cons
- Very small team (~5 employees) with only EUR 1M pre-seed — long-term viability less proven than well-funded competitors
- Smaller community and fewer tutorials compared to LangSmith or Langfuse ecosystems
- Self-hosting requires Kubernetes/Helm for production with known issues on reverse proxy deployments
- Only supports LLM-as-a-judge evaluations — no heuristic or rule-based evaluation options
Helicone or LangWatch — which should you choose?
Choose Helicone if you wantChoose if you want
Choose LangWatch if you wantChoose if you want
- Agent testing before deployment
- Hallucination detection
- Regression testing for LLM apps
- Production monitoring
- Prompt optimization
Compare Helicone and LangWatch on your own traffic
Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 500+ models through one gateway.