GlassFlow ClickHouse ETL is a full-stack, open-source streaming ETL platform designed to ingest data from Apache Kafka (or OpenTelemetry), apply in-flight transformations (deduplication, temporal joins, filtering, stateless transformations), and sink the processed data into ClickHouse with schema evolution support. The system provides a REST API for pipeline lifecycle management, a web UI for visual configuration, and a NATS JetStream backbone for reliable message passing. It supports advanced features like dead-letter queues, schema registry integration (Avro/Protobuf), OpenTelemetry receiver (gRPC/HTTP), and Kubernetes-native deployment via Helm charts. The architecture follows a microservice pattern with distinct roles: ingestor, dedup, join, sink, and OTLP receiver, each running as an independent binary. The Go backend uses a clean component pattern with pluggable processors (filter, dedup, transform) in a chain, backed by PostgreSQL for configuration persistence and BadgerDB for deduplication state. The React/Next.js frontend features a multi-step wizard for pipeline creation, real-time status updates via SSE, and extensive notification channels (toast, modal, banner, Slack, email). The codebase demonstrates high engineering rigor with comprehensive testing (Go unit/integration/BDD tests, Vitest for UI), observability instrumentation (OpenTelemetry, Prometheus metrics), and a design-system approach with Figma tokens. While primarily an application, the repo includes data-focused demos (5G telemetry with OTLP emitter, fraud detection) and a suite of ClickHouse table creation scripts and verification queries, indicating a hybrid character with strong data engineering concerns. The platform specifically targets the challenges of CDC ingestion, backfill, schema evolution, and data quality for ClickHouse sinks.