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Version: 0.14

Introduction

FreshGuard Core is an open-source, MIT-licensed data pipeline freshness monitoring engine. It detects stale data, volume anomalies, and schema changes across PostgreSQL, DuckDB, BigQuery, Snowflake, MySQL, Redshift, SQL Server, Azure SQL, and Azure Synapse.

What it does​

  • Freshness monitoring — Alert when a table hasn't been updated within a tolerance window
  • Volume anomaly detection — Alert when row counts deviate from a calculated baseline
  • Schema change detection — Alert when columns are added, removed, or modified

Who it's for​

  • Teams running data pipelines who want monitoring without SaaS lock-in
  • Self-hosters who want to run on their own infrastructure
  • Developers building custom data quality tooling

Architecture​

CLI / Direct API
        |
Monitoring Algorithms
  checkFreshness · checkVolumeAnomaly · checkSchemaChanges
        |
Database Connectors
  PostgreSQL · DuckDB · BigQuery · Snowflake · MySQL · Redshift · SQL Server · Azure SQL · Azure Synapse
        |
Metadata Storage (optional)
  DuckDB (embedded) or PostgreSQL

Each monitoring function validates its inputs, queries the target database through a connector, analyzes the result, and returns a CheckResult with a status (ok, alert, or failed).

For the full architectural breakdown, see the Architecture doc.

Open Core model​

This package is the open-source core. It contains all monitoring logic, connectors, and CLI tooling under the MIT license. It does not include multi-tenant features, authentication, dashboards, or billing — those are part of the separate FreshGuard Cloud product.

You can use, modify, and distribute this core freely.

Next steps​