Blazer is a Ruby on Rails engine that provides a self-service business intelligence web application. It allows users to run raw SQL queries against multiple databases (PostgreSQL, MySQL, Redshift, BigQuery, Snowflake, 30+ others via pluggable adapters), visualize results as charts and maps, build interactive dashboards, and schedule recurring data quality checks with email or Slack notifications. The architecture follows a monolith Rails engine pattern with clear separation of concerns: adapters for database connectivity, a statement parser for variable substitution, a result caching layer, and controllers/views for the web UI. It also supports anomaly detection and forecasting as optional enhancements. The codebase is well-structured, extensively tested, and actively maintained with frequent releases. Notable patterns include the adapter interface in `lib/blazer/adapters/base_adapter.rb`, the SQL statement parsing in `lib/blazer/statement.rb`, and the execution pipeline in `lib/blazer/run_statement.rb`.