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March 23, 2026

Dashboard Changes in Langfuse v4

Valeriy Meleshkin

Detailed reference for how dashboards behave differently in Langfuse v4 — trace counts, histograms, filters, and more.

With the Langfuse v4 preview, dashboards are powered by a new observation-centric data model. We have published a detailed reference page covering all the changes — what stays the same, what's different, and expected numerical differences when switching between Langfuse v3 and Langfuse v4.

Key changes include:

• Trace counts are now computed as uniq(trace_id) from the wide observations table instead of counting rows in the traces table
• "Traces by time" is replaced by "Observations by time", reflecting the shift to spans as the primary unit
• Score histograms are now computed server-side, including all scores regardless of dataset size
• Trace names fall back to the root span name for OTEL-native ingestion, so previously unnamed traces now display correctly
• High-cardinality dimensions (like userId) now require top-N queries with explicit limits
• NULL and empty strings are treated as equivalent in filters