PlyDB

Free plan LinuxMacWindows

What PlyDB is

PlyDB is an open-source database gateway for querying live data with standard SQL. It connects AI agents to data sources and runs queries directly against them, without moving or staging the data. Agents can use MCP or the PlyDB CLI to discover schemas, run queries, and analyze results; listed compatible agents include Claude, ChatGPT, Gemini, and Codex. A single SQL query can combine data from sources such as PostgreSQL, CSV files, and Google Sheets. PlyDB also supports MySQL, SQLite, DuckDB, JSON, Parquet, Excel, and Amazon S3. Schema discovery helps agents understand available data, while persistent semantic overlays can capture context that is not present in a schema. PlyDB runs locally, and its FAQ says only query results are returned to the AI agent. It is read-only by default; writes require explicit permission. The software is available for Linux, macOS, and Windows as a single binary with no runtime dependencies. PlyDB is free and self-hosted under the Apache 2.0 license. The site identifies Apache Iceberg and Delta Lake support as planned.

Who it suits

PlyDB suits 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.

What it does well

Joins data across sources in one SQL query.
Queries connected sources directly without staging data.
Runs locally; only query results go to the AI agent.
Read-only by default, with writes requiring explicit permission.
Free and open source under Apache 2.0.
Installation commands are available for Linux, macOS, and Windows.

What to know first

The CLI requires shell access.
MCP must be restarted to pick up configuration changes.
Apache Iceberg and Delta Lake support is planned.

Getting started

Visit https://www.plydb.com/.
Install PlyDB using the command for macOS, Linux, or Windows.
Connect a supported data source.
Connect an AI agent through MCP or the PlyDB CLI.
Discover schemas and run SQL queries.

Verdict

Choose PlyDB if you want AI agents to query live sources with SQL while the data stays in your infrastructure. Its cross-source queries, local operation, and read-only default make it a fit for the listed operational and business analysis use cases. The CLI requires shell access, and MCP configuration changes require a server restart.

Questions

Is PlyDB free?

Yes. PlyDB has a free plan and no free trial.

Which operating systems does PlyDB support?

Its platforms are Linux, macOS, and Windows, with installation commands and pre-built binaries for all three.

Which data sources can it query?

Listed sources include PostgreSQL, MySQL, SQLite, DuckDB, CSV, JSON, Parquet, Excel, Amazon S3, and Google Sheets.

Is PlyDB open source?

Yes. It is open source under the Apache 2.0 license.

How do AI agents connect?

Agents connect through MCP or the PlyDB CLI. The site lists Claude, ChatGPT, Gemini, and Codex as compatible.

Does PlyDB change source data?

It is read-only by default. The site says writes require explicit permission.

Facts from PlyDB's own pages

Access control: PlyDB is read-only by default, and its page says writes require explicit permission. · plydb.com, 7 Oct 2026
Agent access: AI agents connect through MCP or the PlyDB CLI to discover schemas, run SQL queries, and analyze data. · plydb.com, 8 Oct 2026
Agent integration: AI agents can connect to PlyDB through MCP or CLI, including Claude, ChatGPT, Gemini, and Codex. · plydb.com, 7 Oct 2026
AI compatibility: The site lists Claude, ChatGPT, Gemini, and Codex among agents that work with PlyDB. · plydb.com, 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. · plydb.com, 8 Oct 2026
Cross-source SQL: PlyDB can join data from sources such as PostgreSQL, CSV files, and Google Sheets in one SQL query. · plydb.com, 7 Oct 2026
Data movement: PlyDB executes queries directly against connected sources without copying or staging data. · plydb.com, 8 Oct 2026
Google Sheets authentication: Google Sheets supports service account authentication for server-side use and browser OAuth for interactive querying. · plydb.com, 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. · plydb.com, 7 Oct 2026
Installation platforms: The installation instructions provide quick-install commands for macOS, Linux, and Windows, and say pre-built binaries are available for all platforms. · plydb.com, 8 Oct 2026
Integration limitation: The CLI requires shell access, while an MCP server must be restarted to pick up configuration changes. · plydb.com, 8 Oct 2026
Intended users: The site presents use cases for DevOps incident response, sales and retention, revenue operations, and executive insights. · plydb.com, 7 Oct 2026
License: PlyDB is open source under the Apache 2.0 license. · plydb.com, 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. · plydb.com, 8 Oct 2026
Maker: The site footer identifies Paul Tzen. · plydb.com, 8 Oct 2026
Planned sources: Apache Iceberg and Delta Lake are listed as planned and are not yet supported. · plydb.com, 8 Oct 2026
Privacy: PlyDB runs locally and queries sources directly; the FAQ says only query results are returned to the AI agent. · plydb.com, 7 Oct 2026
Product: PlyDB is an open-source database gateway that lets AI agents query live data sources using standard SQL. · plydb.com, 7 Oct 2026
Read-only behavior: PlyDB is read-only by default, and the site says agents cannot alter original data unless explicitly allowed. · plydb.com, 8 Oct 2026
Semantic context: PlyDB automatically scans sources for schemas, tables, columns, types, and database COMMENT metadata to provide agents with semantic context. · plydb.com, 8 Oct 2026
Supported sources: Supported sources include PostgreSQL, MySQL, SQLite, DuckDB, CSV, JSON, Parquet, Excel, Amazon S3, and Google Sheets. · plydb.com, 8 Oct 2026
What it does: PlyDB is an open-source database gateway that lets AI agents query live data sources using standard SQL. · plydb.com, 8 Oct 2026

Where PlyDB stands on Freedom251

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