Google Stax is free, with no paid plan attached. OpenLLMetry (Traceloop) is free, with no paid plan attached. Both are listed under LLM Eval & Observability, so this is a like-for-like comparison. Neither is ranked above the other — Flocci carries no sponsored placement.
Google Stax is free, with no paid plan attached and is listed for build evals with human raters or LLM autoraters on your own data. OpenLLMetry (Traceloop) is free, with no paid plan attached and is listed for openTelemetry-based instrumentation for LLM calls, vector DBs and frameworks. Both sit in LLM Eval & Observability.
Neither — Google Stax and OpenLLMetry (Traceloop) are both free, so the choice comes down to capability rather than cost. Both entries list what they uniquely do above.
Choose Google Stax if you need build evals with human raters or LLM autoraters on your own data; choose OpenLLMetry (Traceloop) if you need openTelemetry-based instrumentation for LLM calls, vector DBs and frameworks. Flocci AI Tools does not rank one above the other — it shows both feature sets side by side and lets the requirement decide.
| Google Stax | OpenLLMetry (Traceloop) | |
|---|---|---|
| Pricing tier | Free | Free |
| Free to start | Yes | Yes |
| Category | AI Models & Local Execution | AI Models & Local Execution |
| Type | LLM Eval & Observability | LLM Eval & Observability |
| Listed capabilities |
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| Tags | google stax, llm evaluation tool, free prompt evaluation, llm as judge autoraters, compare llm prompts | openllmetry, opentelemetry llm, traceloop, llm observability open source, otel ai tracing |
| Website | stax.withgoogle.com | github.com |
| Full page | Google Stax details → | OpenLLMetry (Traceloop) details → |
| Alternatives | Google Stax alternatives → | OpenLLMetry (Traceloop) alternatives → |