Pulse

Pulse is a compact chart strip above the events table. Each bar covers a slice of time and shows the worst single event in that slice: the most expensive call, the slowest response, the biggest token burst. The spike you are hunting for is a tall bar, not a row you have to sort your way down to. Click or drag a spike and the table narrows to that window.

Pulse is open by default above the events table. Close it with the × in its top-right corner, and reopen it with the Pulse button in the table toolbar.

What each bar shows

Each bar is one time bucket. Its height is a single aggregate of the events in that bucket, so a tall bar is a bucket that holds an outlier. The default aggregate is the maximum, so a bar shows the worst single event in its slice.

The bars span the full selected time range. A bucket with no events is a gap on the baseline rather than absent space, so a quiet stretch reads as a flat baseline and a spike stands out against it. Bars use a square-root height scale: real cost and latency outliers run many times the base load, and a linear scale would flatten everything but the peak, so the scale keeps the base load readable while the outlier still dominates.

Bucket width adapts to the range and the available width. Langfuse picks the finest bucket that fits the range into the strip, from one minute up to one week, so a one-hour range and a one-month range both fill the strip with bars.

Hover a bar to read its time bucket, the metric value, and how many events fell in it. When events exist in a bucket but carry no value for the current metric, the bar shows a faint activity tick instead of a height, so a missing metric never reads as "nothing happened". When the range holds no events at all, the strip reads No events in range; when it holds events but none carry the current metric, it reads No [metric] data in range.

Metric modes

A dropdown at the left of the strip switches what the bars plot:

• Cost
• Latency
• Tokens
• Split shows Cost, Latency, and Tokens side by side at once.

Split fits three charts when the strip is wide enough, drops to Cost and Latency on a narrower strip, and is offered as an option only when at least two fit.

Each metric plots the aggregate that fits it. Where a metric offers more than one aggregate, a second dropdown next to the metric name switches it:

max is the outlier view: each bar is the single worst event in its bucket. sum, p95, and avg describe the bucket as a whole instead. Your metric and aggregate choices are remembered across visits.

Navigate to an outlier

Pulse turns spotting a spike into navigating to it.

• Click a bar and the table's time range narrows to that bucket, showing exactly the events in the spike.
• Drag across a range of bars to select a wider span. The selection applies when you release.
• Browser Back returns you to the range you started from, so exploring costs you nothing.

An empty bucket does not navigate, since there would be nothing to show.

On touch devices, a tap or drag previews the span with a pinned tooltip and an Explore this window action instead of changing the range immediately, so an accidental touch never moves you.

Filters it applies

Pulse plots the same filtered query as the events table below it. The time range, the sidebar facets, and the search bar all carry over.

A few filters cannot be expressed as an aggregate over time, so the strip cannot apply them:

• Numeric measures used as filters (filtering by latency, cost, or token value). These are still available as strip metrics; only filtering the rows by their value is unavailable.
• Scores, metadata, and comments filters.
• Full-text search and field-scoped text search (input:, output:).
• Presence checks (has: and -has:).

When any of these are active, the strip shows a "N filters not applied" note. The table still honors those filters; only the strip shows the unfiltered distribution for them. This is the reverse of chart view, where those filters are dimmed instead, because the chart replaces the table rather than sitting above it.

Pulse and charting the table

Pulse and Chart any table both draw the events table's data, but they answer different questions. Pulse is an always-on strip above the table for finding and jumping to outliers, one bar per time bucket, with the worst event as the default. Charting the table replaces the table with a full, configurable chart (type, metric, aggregation, breakdown) of the same filtered query, and can be saved to a dashboard. Use Pulse to spot and drill into a spike; switch to a chart when you want to shape a view and keep it.

Learn more

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