MotherDuck is a managed cloud platform for DuckDB analytics. PlyDB is an open-source gateway that connects AI agents to many data sources — including DuckDB — with zero ETL and native MCP support. They serve different roles, and can work together.
| MotherDuck | PlyDB | |
|---|---|---|
| DuckDB support | The canonical cloud deployment of DuckDB | DuckDB as a local source |
| Team collaboration & sharing | Org sharing, ACL-based access, zero-copy DB cloning | Not supported |
| Fully managed / serverless | No infrastructure to run; auto-scaling compute | Local / self-hosted |
| Hybrid local + cloud execution | Join local DuckDB data with cloud-hosted tables in one query | Not applicable |
| Agent integration (MCP) | First-party MCP server — queries MotherDuck data (Claude, ChatGPT, Cursor) | MCP & CLI — queries any live source |
| Semantic context for agents | SQL Assistant (basic AI features) | Auto-discovery + OSI overlays that compound across sessions |
| File & object storage queries | S3, GCS, Azure, Parquet, CSV, JSON, Iceberg, Delta Lake | S3, Parquet, CSV, Excel, Google Sheets |
| PostgreSQL / MySQL live queries | Load into MotherDuck first (PostgreSQL server-side support on roadmap) | Direct, no loading required |
| Cross-source joins | Within DuckDB-compatible sources | Across any connected source (powered by DuckDB) |
| Open source | Proprietary SaaS (built on open-source DuckDB) | Full product, Apache 2.0 |
| Pricing | Free tier; pay-as-you-go compute + storage | Open source |
MotherDuck is the canonical cloud deployment of DuckDB — backed by DuckDB Labs itself. It takes the speed and SQL expressiveness of DuckDB and adds the things local DuckDB lacks: cloud scale, team collaboration (org-wide sharing, ACLs, zero-copy database cloning), and hybrid local+cloud query execution that routes work between your machine and the cloud automatically. It queries files and object storage (S3, GCS, Parquet, Iceberg, Delta Lake) directly without loading. A first-party MCP server connects AI agents like Claude and ChatGPT to your MotherDuck data. Live federation from PostgreSQL and MySQL databases requires a local load step today; server-side PostgreSQL support is on their roadmap.
PlyDB is an open-source gateway built from the ground up for AI agents — powered by DuckDB as its query engine, but designed to reach beyond the DuckDB ecosystem. You declare your sources in a single JSON config file: PostgreSQL, MySQL, SQLite, files, S3, Google Sheets — each needing only a type and connection details to become immediately queryable. Any AI agent connects via MCP or CLI with no custom connectors, no cloud account, and no loading step for relational databases. PlyDB also ships a semantic context system: automatic schema discovery plus an OSI-format overlay system where agents record and share institutional knowledge — enum meanings, business rules, domain context — that compounds across sessions so every future query benefits from what was learned before.
These tools can complement each other. PlyDB supports DuckDB as a local data source — so if your team uses DuckDB (with or without MotherDuck), PlyDB can expose it to AI agents alongside your other data sources, without any additional ETL work.
DuckDB, PostgreSQL, S3, CSV, Google Sheets — query them all from a single AI agent. No ETL. No lock-in.
Apache License 2.0