Langfuse icon

Langfuse

Log LLM traces, spans, generations, and scores to Langfuse, or query traces, prompts, datasets, sessions, and more via the Public API.

Actions28

Ingestion → Event Create

AI-generated

Summary

Create a new event observation in Langfuse with optional detailed metadata and timestamps to log domain-specific events within a trace.

Inputs

  • Name (required) — Human-readable name for the event observation.
  • Input JSON — JSON string representing the input payload associated with the event.
  • Output JSON — JSON string representing the output payload associated with the event.
  • Trace ID — Trace ID to associate this event with; if not provided, it auto-fills from previous node output to continue a trace chain.
  • Event ID — Optional unique event ID used for idempotency and deduplication of this event.
  • Observation ID — Optional observation ID; left blank to auto-generate a new one for create operations.
  • Parent Observation ID — Optional parent observation ID to create nested or hierarchical event relationships.
  • Timestamp — ISO 8601 timestamp of the event; uses current time if blank.
  • Environment — Optional environment label to categorize the event, e.g., production or staging.
  • Metadata JSON — Additional arbitrary metadata as a JSON string to augment the event record.
  • Version — Optional version string to specify event versioning.
  • Level — Optional log or observation level, e.g., info, warning, error.
  • Status Message — Optional status message describing the event's state or outcome.
  • Fail On Batch Errors — Boolean to fail the workflow item if Langfuse returns partial ingestion errors during batch submissions.

Output shape

a single event record including assigned or provided IDs and metadata returned by Langfuse ingestion API

The operation returns the created event observation details, including generated IDs such as traceId and observationId when not explicitly provided. Partial ingestion errors can be surfaced if "Fail On Batch Errors" is set; otherwise, partial failures won't cause node failure. Timestamp defaults to current time if omitted.

Examples

Example 1: Create an event logging a user action with input and output payloads, auto-linking to an existing trace

Set Name to describe the event, provide Input JSON and Output JSON payloads, and leave Trace ID blank to auto-associate with prior step's trace.

Links

Discussion