Open-Source Databases · ankane

blazer

Blazer is a Ruby-based business intelligence tool that lets teams explore databases with SQL and create interactive dashboards, charts, and alerts. It integrates into Rails apps, supports multiple database backends, and includes features like query auditing, data checks, and variable-driven reports.

Talk to DEV.co Discuss Implementation

Source: GitHub — github.com/ankane/blazer

4.8k

GitHub stars

499

Forks

Ruby

Primary language

MIT

License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

Field	Value
Repository	ankane/blazer
Owner	ankane
Primary language	Ruby
License	MIT — OSI-approved
Stars	4.8k
Forks	499
Open issues	31
Latest release	Unknown
Last updated	2026-06-25
Source	https://github.com/ankane/blazer

What blazer is

Blazer is a Rails engine providing a web UI for SQL query execution against PostgreSQL, MySQL, Redshift, and other databases. It offers parameterized queries, automatic chart generation based on result schema, scheduled checks with email/Slack alerts, and role-based access control via authentication hooks.

Quickstart

Get the blazer source

Clone the repository and explore it locally.

terminalbash

1git clone https://github.com/ankane/blazer.git2cd blazer3# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

Internal analytics dashboards for existing Rails applications

Teams already running Rails can mount Blazer as an engine to provide non-technical stakeholders with self-service SQL exploration and pre-built dashboards without building custom BI infrastructure.

Data quality monitoring and anomaly detection

Use Blazer's scheduled checks to run periodic queries against data sources and trigger email or Slack alerts when metrics fall outside acceptable ranges, automating operational monitoring.

Audit-friendly SQL analytics with full query history

Organizations requiring compliance or data governance benefit from Blazer's built-in query auditing, which tracks all executed SQL and results, essential for regulated industries.

Implementation considerations

Requires a Rails application and database connectivity; integration is via Gemfile addition and route mounting. Production setup requires environment variables for database URLs and authentication secrets.
Database permissions must be carefully managed—use read-only database roles to prevent accidental or malicious data modification, as Blazer's transaction rollback is noted as not foolproof.
Scheduled checks (alerts, anomaly detection) require a background job scheduler (cron, Solid Queue, Heroku Scheduler, etc.); ensure infrastructure supports recurring task execution.
Authentication must be explicitly configured (basic auth, Devise, or custom before_action). Do not expose Blazer endpoints without authentication in production.
Sensitive data handling via Hypershield or blind indexing is optional but recommended if the database contains PII or regulated data.

When to avoid it — and what to weigh

Standalone BI platform requirement — Blazer is a Rails engine, not a standalone application. If your stack is not Ruby/Rails or you need an independent BI tool, consider dedicated platforms like Metabase or Looker.
Complex multi-tenant SaaS with strict data isolation — Blazer's permission model integrates with your Rails authentication system; building robust multi-tenant isolation requires careful custom configuration and is not built-in.
Real-time analytics on massive datasets — Blazer executes ad-hoc SQL queries and caches results; it is not optimized for sub-second queries across petabyte-scale data warehouses. Data warehouse query engines like Presto are better suited.
Advanced data modeling and semantic layers — Blazer lacks sophisticated semantic layer features (dimensions, measures, hierarchies). Teams needing rich data models should evaluate Cube.js or similar platforms.

License & commercial use

Blazer is licensed under the MIT License, a permissive OSI-approved license that permits commercial use, modification, and distribution with minimal restrictions. Attribution is requested but not legally required.

MIT License permits commercial use without license fees or proprietary restrictions. However, ensure your Rails application and any deployed infrastructure comply with your own commercial and compliance requirements. No warranty or support guarantees are provided by the license.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

Signal	Assessment
Maintenance	Active
Documentation	Adequate
License clarity	Clear
Deployment complexity	Low
DEV.co fit	Good
Assessment confidence	High

Security considerations

Blazer executes arbitrary user-submitted SQL queries. Key considerations: (1) Protect endpoints with authentication—default to no auth; configure basic auth, Devise, or custom before_action. (2) Use read-only database roles to mitigate accidental or intentional data modification. (3) SQL injection: Blazer uses parameterized queries for variables, but users can write arbitrary SQL; assume users have query-level data access. (4) Audit all queries (built-in); review logs for suspicious patterns. (5) Sensitive data (PII) should be shielded using Hypershield or similar. (6) No mention of role-based query access control (RBAC) beyond authentication; query-level permissions rely on database permissions. (7) Deployment must protect credentials (database URLs, secrets) via environment variables, not code.

Alternatives to consider

Metabase

Standalone, language-agnostic BI platform with rich UI, data modeling, and RBAC. Does not require Rails; better for multi-team, multi-source analytics. More feature-complete but higher operational overhead.

Superset (Apache)

Open-source data visualization platform with semantic layer, advanced charting, and SQL exploration. Suitable for larger teams and data warehouses. Requires separate Python/Flask deployment.

Looker (by Google)

Commercial BI platform with semantic modeling, RBAC, and enterprise features. Ideal for regulated organizations needing governance and audit trails. Significantly higher cost and complexity.

Software development agency

Build on blazer with DEV.co software developers

Blazer integrates in minutes and requires no standalone infrastructure. Contact us to evaluate Blazer or build custom BI solutions for your team.

Talk to DEV.co

Related open-source tools

Surfaced by semantic similarity across the DEV.co open-source index.

glaredb scalardb bundler-audit

Related on DEV.co

Explore the category and the services that help you build with it.

Open-Source Databases Web App Development API Development Custom Software Development Talk to DEV.co

blazer FAQ

Can I use Blazer without Rails?

Blazer is a Rails engine, so it requires a Rails application to function. However, a standalone Docker image (blazer-docker) is available for deployments that do not use Rails directly.

Is my data safe if I expose Blazer on the internet?

No, not by default. Blazer has no built-in authentication; you must configure authentication (basic auth, Devise, custom before_action) and use read-only database roles. Never expose Blazer without these controls in production.

How do I prevent users from deleting or modifying data via Blazer?

Blazer attempts transaction rollback for data-modifying queries, but this is not foolproof. The safest approach is to use a read-only database user with only SELECT permissions. The README provides SQL examples for PostgreSQL and MySQL.

Does Blazer support real-time data or streaming?

No. Blazer executes ad-hoc SQL queries and caches results. It is not designed for real-time streaming or sub-second latency analytics on large datasets.

Software development & web development with DEV.co

DEV.co is a software development agency delivering custom software development services to companies building on open source. Our software developers and web developers design, integrate, and ship production systems — spanning web development, APIs, AI, data, and cloud. If blazer is part of your open-source databases roadmap, our team can implement, customize, migrate, and maintain it.

Ready to add self-service analytics to your Rails app?

Blazer integrates in minutes and requires no standalone infrastructure. Contact us to evaluate Blazer or build custom BI solutions for your team.

Talk to DEV.co Schedule a Consultation