PlyDB
PlyDB is a free, open-source database gateway that lets AI agents query live data sources with standard SQL.
What PlyDB is
PlyDB is a free, open-source database gateway that lets AI agents query live data sources with standard SQL. It runs locally and sends queries directly to connected sources instead of moving or staging the data. Agents connect through MCP or the PlyDB CLI to discover schemas and run queries; listed compatible agents include Claude, ChatGPT, Gemini, and Codex. A single query can combine sources such as PostgreSQL, CSV files, and Google Sheets. Other supported sources include MySQL, SQLite, DuckDB, JSON, Parquet, Excel, and Amazon S3. Schema discovery helps agents identify available data, while persistent semantic overlays can preserve context beyond the schema. PlyDB is read-only by default, and writes require explicit permission. Its FAQ says data stays in the user's infrastructure and only query results are returned to the AI agent. Installation instructions cover Linux, macOS, and Windows, with pre-built single binaries that have no runtime dependencies. The CLI requires shell access, and an MCP server must be restarted to pick up configuration changes. PlyDB is self-hosted under the Apache 2.0 license; Apache Iceberg and Delta Lake support are planned.
Good
- Free and open source under Apache 2.0.
- Queries connected sources without moving or staging data.
- One SQL query can join multiple source types.
- Read-only by default; writes need explicit permission.
- Available for Linux, macOS, and Windows.
Watch out
- The CLI requires shell access.
- MCP server restarts are needed after configuration changes.
- Apache Iceberg and Delta Lake support is planned, not available.
Who it suits
PlyDB may suit people who want AI agents to query live databases and files with SQL while keeping data in their own infrastructure. Its listed use cases include DevOps incident response, sales and retention, revenue operations, and executive insights.
Verdict
PlyDB provides local, SQL-based access to a broad set of data sources for compatible AI agents. Consider the shell-access and MCP configuration requirements when choosing how to connect.
The facts
Each one read from PlyDB's own pages, with the date it was checked.
What it does
- Access control
- PlyDB is read-only by default, and its page says writes require explicit permission.checked 7 Oct 2026
- Agent access
- AI agents connect through MCP or the PlyDB CLI to discover schemas, run SQL queries, and analyze data.checked 8 Oct 2026
- Agent integration
- AI agents can connect to PlyDB through MCP or CLI, including Claude, ChatGPT, Gemini, and Codex.checked 7 Oct 2026
- AI compatibility
- The site lists Claude, ChatGPT, Gemini, and Codex among agents that work with PlyDB.checked 8 Oct 2026
- Cross-source queries
- PlyDB can federate sources so a single SQL query can join data such as a PostgreSQL table, CSV file, and Google Sheet.checked 8 Oct 2026
- Cross-source SQL
- PlyDB can join data from sources such as PostgreSQL, CSV files, and Google Sheets in one SQL query.checked 7 Oct 2026
- Data movement
- PlyDB executes queries directly against connected sources without copying or staging data.checked 8 Oct 2026
- Google Sheets authentication
- Google Sheets supports service account authentication for server-side use and browser OAuth for interactive querying.checked 8 Oct 2026
- Installation
- The site provides installation commands for macOS, Linux, and Windows and describes PlyDB as a single binary with no runtime dependencies.checked 7 Oct 2026
- Integration limitation
- The CLI requires shell access, while an MCP server must be restarted to pick up configuration changes.checked 8 Oct 2026
- Intended users
- The site presents use cases for DevOps incident response, sales and retention, revenue operations, and executive insights.checked 7 Oct 2026
- License
- PlyDB is open source under the Apache 2.0 license.checked 8 Oct 2026
- Local operation
- PlyDB runs locally and queries sources directly; the FAQ says data stays in the user's infrastructure and only query results go to the AI agent.checked 8 Oct 2026
- Privacy
- PlyDB runs locally and queries sources directly; the FAQ says only query results are returned to the AI agent.checked 7 Oct 2026
- Product
- PlyDB is an open-source database gateway that lets AI agents query live data sources using standard SQL.checked 7 Oct 2026
- Read-only behavior
- PlyDB is read-only by default, and the site says agents cannot alter original data unless explicitly allowed.checked 8 Oct 2026
- Semantic context
- PlyDB automatically scans sources for schemas, tables, columns, types, and database COMMENT metadata to provide agents with semantic context.checked 8 Oct 2026
- Supported sources
- Supported sources include PostgreSQL, MySQL, SQLite, DuckDB, CSV, JSON, Parquet, Excel, Amazon S3, and Google Sheets.checked 8 Oct 2026
- What it does
- PlyDB is an open-source database gateway that lets AI agents query live data sources using standard SQL.checked 8 Oct 2026
Where it runs
- Installation platforms
- The installation instructions provide quick-install commands for macOS, Linux, and Windows, and say pre-built binaries are available for all platforms.checked 8 Oct 2026
The company
- Maker
- The site footer identifies Paul Tzen.checked 8 Oct 2026
Money
- Planned sources
- Apache Iceberg and Delta Lake are listed as planned and are not yet supported.checked 8 Oct 2026
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