> ## Documentation Index > Fetch the complete documentation index at: https://docs.evidentlyai.com/llms.txt > Use this file to discover all available pages before exploring further. # Overview > Introduction to Tracing. Trace store and viewer are available in **Evidently OSS, Evidently Cloud** and **Evidently Enterprise**. Tracing uses the open-source `Tracely` library, based on OpenTelemetry. ## What is LLM tracing? Tracing lets you instrument your AI application to collect data for evaluation and analysis. It captures detailed records of how your LLM app operates, including inputs, outputs and any intermediate steps and events (e.g., function calls). You define what to include. Evidently provides multiple ways to explore tracing data. See a timeline of execution steps with input-output details and latency.

Automatically generate a tabular view for easier evaluation or labeling.

For conversational applications, browse traces by user or session to focus on chat flows.

Once you capture the data, you can also run evals on the tracing datasets. ## Do I always need tracing? Tracing is optional on the Evidently Platform. You can also: * Upload tabular datasets using Dataset API. * Run evals locally and send results to the platform without tracing. However, tracing is especially useful for understanding complex LLM chains and execution flows, both in experiments and production monitoring.