traceloop.com · Observability
OpenTelemetry based instrumentation for LLM providers and frameworks, sending traces to any observability backend.
OpenLLMetry is one of 10 observability tools on TrueIQ. See all observability tools or how we check facts.
// guides
Datadog LLM Observability vs Langfuse: how each bills (LLM spans vs units), retention, self hosting, evals and setup, with worked cost examples for 2026.
AI agent observability explained: trace tool loops, permissions and memory, the six PAI telemetry gaps, and which tools fit, from Langfuse to Datadog.
The best LLM observability tools in 2026 compared: Langfuse, LangSmith, Phoenix, Opik, Weave and more, with licenses, self hosting and who now owns what.
Langfuse vs LangSmith in 2026: open source license, self hosting, pricing, retention, framework fit and migration tips, so you can pick the right LLM tracer.
Langfuse vs Arize Phoenix in 2026: licenses, self hosting stacks, features, managed pricing, new owners and which open LLM tracing tool fits your team best.
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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
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
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
Heliconehelicone.aiOpen source LLM gateway and request logger for tracking cost, latency and usage. Acquired by Mintlify in March 2026; the hosted service now runs in maintenance mode.ObservabilityOpen source★ 6.2k