What is blazer?

Blazer is a business intelligence tool built for Ruby on Rails applications. It lets anyone on your team write SQL queries to explore data in your database, then turn those queries into charts, dashboards, and scheduled alerts, all served through a web interface that sits inside your existing Rails app. The project was originally built and battle-tested at Instacart. The core idea is straightforward: you write a SQL query, Blazer runs it against your database, and automatically picks a chart type based on the columns you return. A query returning a timestamp and a number becomes a line chart. A query returning a string and a number becomes a bar chart. Dashboards are just collections of saved queries displayed together. No separate data warehouse or special setup is required beyond your existing database. Blazer connects to many database types including PostgreSQL, MySQL, Redshift, and others. It supports variables inside queries so you can reuse the same query with different filter values without rewriting it. You can define human-friendly dropdown options for those variables so teammates can pick values by name rather than remembering internal IDs. The checks and alerts feature lets you define queries that should return zero rows (or meet some condition), and email your team when that condition breaks. For example, you could alert when orders have been stuck in a certain state for too long. Checks can run on a schedule via cron, Solid Queue, or similar tools, and can also send notifications to Slack. Security is handled by plugging into whatever authentication system your Rails app already uses, such as Devise or a custom admin check. Blazer can also run queries through a read-only database user to prevent accidental data modification. All queries are logged in an audit trail so you can see who ran what and when.