W&B Weave
wandb.ai · Observability
Weights & Biases toolkit for tracing, evaluating and iterating on LLM applications.
W&B Weave is one of 10 observability tools on TrueIQ. See all observability tools or how we check facts.
Freemium
// guides
Guides that cover W&B Weave
Best LLM Observability Tools in 2026, Compared
The best LLM observability tools in 2026 compared: Langfuse, LangSmith, Phoenix, Opik, Weave and more, with licenses, self hosting and who now owns what.
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W&B Weave alternatives and related tools
Langfuselangfuse.comOpen source LLM engineering platform (MIT core) for tracing, prompt management, datasets and evals, free to self host. Owned by ClickHouse since January 2026.ObservabilityOpen source★ 36.6k
Laminarlaminar.shOpen source observability platform for AI agents with tracing, evaluations and browser session replays.ObservabilityOpen source★ 3.5k
Opikcomet.comComet's open source platform for logging, evaluating and monitoring LLM apps, RAG systems and agents.ObservabilityOpen source★ 23k
Arize Phoenixarize.comFree, self hostable tracing and evaluation tool built on OpenTelemetry, source available under the Elastic License 2.0. Arize became part of Dynatrace in October 2026.ObservabilityFree★ 12k
LangSmithlangchain.comLangChain's platform for tracing, evaluating and monitoring LLM apps and agents, framework agnostic.ObservabilityFreemium
Datadog Agent Observabilitydatadoghq.comDatadog's hosted tracing and evaluation product for LLM apps and agents (formerly LLM Observability), billed per LLM call and linked to Datadog APM and infrastructure data.ObservabilityFreemium