Apache Flagon
Instrument Software. Understand Humans.
Apache Flagon is an open-source, thin-client behavioral logging and analytics suite for web observability, usability engineering, and product analytics. Combine lightweight browser instrumentation with Python behavioral data science to build the stack that fits your infrastructure:
With a single line of code, capture user behavior across your web application with the resolution needed for full-stack observability and behavioral modeling. Apache UserALE.js features pluggable exporters (
http-json, otlp, proto-json, websocket), W3C Trace Context (traceparent) correlation, and two-layer session replay. Try the interactive demo below!
Interactive UserALE.js 2.5 Live Telemetry Demo
Interact with the controls below to inspect live telemetry generated in your browser by UserALE.js 2.5. Switch between UserALE Flat JSON, OpenTelemetry (OTLP/JSON), and Protobuf v1 (LogBatch) wire formats in real time.
1. Standard UI Interactions
2. Behavioral & Session Replay Signals (2.5)
Rapidly click the button below 3+ times to trigger RageClickDetector (rage_click + normalized targetRect bounding box), or mutate the DOM to emit a debounced mutation summary log.
3. Forms & Privacy Controls (data-userale-redact)
Select Component
4. Spatial Viewport & Map Interaction
Process and own your user event data. Apache Flagon Distill is a Python behavioral analytics framework that ingests UserALE flat JSON, Protobuf v1
LogBatch JSON, and OpenTelemetry OTLP/JSON payloads—giving data scientists and engineers built-in algorithms for session segmentation, UX frustration detection (rage clicks, dead clicks, DOM thrashing), spatial click/scroll heatmaps, and Markov clickstream graphs.
About the Project
Apache Flagon is a free and open-source, thin-client behavioral logging solution for business analytics, usage analytics, usability testing and scientific research. Formerly named Apache SensSoft, Flagon had its start at Draper for DARPA's XDATA program and represents the hard-work and innovations of an interdisciplinary team of data scientists, psychologists, developers and system architects. Apache Flagon is maintained by the people that love it under the mentorship and guidance of the Apache Software Foundation. Join the conversation and the community!
