> ## Documentation Index
> Fetch the complete documentation index at: https://launchdarkly-preview.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Traces
> This topic explains how to use LaunchDarkly's observability features to trace session activity through your application.
> For the complete documentation index, see [llms.txt](/llms.txt). For the full documentation snapshot, see [llms-full.txt](/llms-full.txt).
## Overview
This topic explains how to use LaunchDarkly's observability features to trace session activity through your application. Traces let you filter on spans of traces in your product based on a query. The **Traces** view shows a summary of traces, including the number of traces and the latency associated with them over time.
Hover on any span and click **Open** to view more details about it, including the span duration, details about the initiating event, and information about the telemetry. Click **View session** or **View logs** to see the span's related session or logs.
## Get started
To instrument your application to capture traces, read the documentation on [Observability SDKs](/sdk/observability). The functionality is available through plugins to the LaunchDarkly JavaScript SDK.
To view traces:
1. In the left navigation, expand **Observe**.
2. Click **Traces**.
3. Select a trace from the list.
## Search
To learn more about the search specification for the **Traces** view, read [Search specification](/home/observability/search).
When you search on the **Traces** view, the following behaviors apply by default:
* The default search [key](/home/observability/search#keys-and-values) is `span_name`. For example, if you enter an expression without a key, such as `search-term`, then LaunchDarkly automatically expands that to `span_name=*search-term*`.
### Search attributes
By default, the [observability SDK plugin](/sdk/observability) automatically injects the following attributes to provide additional help with searching for traces:
\| Category
\| Attribute
\| Description
| Example |
| - |
\| ---
\| ---
\| --- |
\| Feature flag
\| `feature_flag`
\| Produces a list of spans that are associated with a feature flag. You can refine results with the following additional attributes: `context.id` , `contextKeys` , `key` , `provider.name` , `result.reason.inExperiment` , `result.reason.kind` , `result.value` , `set.id` , and `.variant` .
\| `true` |
\| Service or application
\| `environment`
\| The environment key, based on the SDK credentials used in the [Observability SDKs](/sdk/observability) .
\| `production` |
\| `secure_session_id`
\| Session ID that contains the span.
\| `wh1jcuN5F9G6Ra5CKeCjdIk6Rbyd` |
\| `service_name`
\| Name of the service specified in the SDK plugin. To learn more, read [Versioning sessions and errors](/sdk/features/observability-config-client-side#versioning-sessions-and-errors) .
\| `private-graph` |
\| `service_version`
\| Version of the service specified in the observability SDK plugin. To learn more, read [Versioning sessions and errors](/sdk/features/observability-config-client-side#versioning-sessions-and-errors) .
\| `e1845285cb360410aee05c61dd0cc57f85afe6da` |
\| Trace properties
\| `duration`
\| Time length of the span. Defaults to nanoseconds. Use `s` , `m` , or `h` suffixes to designate seconds, minutes, or hours.
\| `10s` |
\| `has_errors`
\| Whether the span has an error tied to its ID.
\| `true` |
\| `parent_span_id`
\| Span ID of the span's parent.
\| `327611203ec5b0a1` |
\| `span_kind`
\| Broad source of the span.
\| `Browser` |
\| `span_name`
\| Title of the span.
\| `POST https://app.launchdarkly.com` |
\| `trace_id`
\| Trace ID of the spans.
\| `7654ff38c4631d5a51b26f7e637eea3c` |