Midplane

Midplane is an MCP gateway that sits between AI assistants and a Postgres database. It checks every statement before it reaches the database, blocking risky operations such as updates or deletes without a WHERE clause, schema changes, and writes hidden inside read-looking queries. It also masks sensitive fields, prevents prompt-injection instructions in data from triggering actions, and keeps the database password and rows within the user's own network.

The gateway parses statements with Postgres's own parser, applies field masking inside queries, binds approvals to a single exact statement, and logs every query before execution. It works with Claude, ChatGPT, Cursor, VS Code, and other MCP clients, and can run locally or in the user's cloud. Midplane Cloud adds team approvals, SSO, shared rules, an audit view, and EU or US region selection. The local edition is free and open source under an MIT license, with rules in a policy file and a local query log; the cloud edition is aimed at teams needing shared governance across gateways.