MLCraft
Open source semantic layer for centralized metrics management
About MLCraft
MLCraft (now Synmetrix) is an open source data engineering platform and semantic layer built on Cube. It provides a complete framework for modeling, integrating, transforming, aggregating, and distributing metrics data at scale, serving as a modern alternative to Looker.
Pros & Cons
Pros
- Fully open source with permissive dual licensing (Apache 2.0 / MIT)
- Built on proven Cube.js engine with excellent query performance and caching
- Supports 50+ data sources including all major cloud data warehouses
- Self-hosted deployment gives full control over data privacy and security
- Visual data exploration makes metrics accessible to non-technical users
- Schema versioning provides auditability and governance capabilities
Cons
- Requires self-hosting and Docker knowledge — no managed cloud offering
- Smaller community compared to established BI tools like Looker or Metabase
- Documentation could be more comprehensive for advanced use cases
- Limited to 608 GitHub stars, indicating a niche but growing user base
- Setup and initial configuration can be complex for non-technical teams
Key Features
Semantic Layer on Cube
Flexibly define metrics and dimensions using SQL and Cube data models to create a single source of truth across your organization
SQL API
Distribute metrics downstream to any consumer via a SQL API, integrating with BI tools, dashboards, and data science workflows
Caching & Pre-aggregations
Uses Cube Store as a purpose-built caching and query execution layer optimized for fast aggregations and time series data
Scheduled Reports & Alerts
Monitor metrics with scheduled reports and real-time alerts with notification capabilities for critical data events
Schema Versioning
Track schema changes over time with built-in versioning for full auditability and governance
Role-Based Access Control
Set personalized user permissions and data security policies to control who can access which metrics
50+ Data Source Connectors
Seamlessly connect to BigQuery, Snowflake, ClickHouse, Redshift, Databricks, PostgreSQL, and many more
Data Exploration UI
Visual data exploration interface that makes data accessible to non-technical users without requiring SQL knowledge
Self-Hosted Deployment
Deploy on your own infrastructure with Docker Compose for full control over data and security
Pricing
- Full platform features
- Self-hosted via Docker
- Community support on Slack
- Apache 2.0 / MIT license
- Unlimited users
- 50+ data source connectors
- Everything in Open Source
- Priority support
- Custom integrations
- SLA guarantees
- Dedicated onboarding
Best For
Centralized Metrics Layer
Create a single source of truth for business metrics across multiple data warehouses, eliminating inconsistent definitions across teams
Self-Service Analytics
Enable business analysts and decision makers to explore data and generate queries without SQL knowledge through the visual interface
Open Source Looker Alternative
Replace proprietary BI tools like Looker with a self-hosted, open source semantic layer that integrates with existing BI tools via SQL API
Data Engineering Pipeline
Build real-time data transformation pipelines with caching, pre-aggregations, and multi-source integration for production workloads
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