Interactive ER diagrams
Automatic layout, crow's-foot notation, focus on a table and its neighbours, saved subject-area diagrams, and the join path between any two tables as ready SQL.
DB Mastermind
The database client that
understands your data
Browse and filter data without limits, draw and redesign your schema with generated migrations, and ask an AI that knows your database. Free and open source, nothing to install on Windows.
Windows: portable zip, just unzip and run · macOS (Apple Silicon & Intel) · Linux AppImage / deb
Scoop:
scoop install https://github.com/eLh0m3r0/db-mastermind/releases/latest/download/db-mastermind.jsonHomebrew:
brew tap elh0m3r0/db-mastermind https://github.com/eLh0m3r0/db-mastermind && brew install --cask db-mastermind- PostgreSQL
- SQL Server
- Oracle
- MySQL
- MariaDB
- SQLite
- DuckDB
- ClickHouse
- CockroachDB
- BigQuery
- Trino
- CSV · Parquet · Excel
Everything you do every day, done well
No row limits, no paywalled features. English and Czech UI.
Advanced filters
Nested AND/OR groups, 25+ operators (in list, between, regex, last N days, this month), raw WHERE, or describe the filter in plain words.
SQL editor
Schema-aware autocomplete that writes whole JOINs from foreign keys, snippets, parameters, execution plans, history and saved queries.
Query any file
Drop a CSV, Parquet, JSON or Excel file on the window and query it with SQL. Czech exports with decimal commas just work.
Charts & dashboards
Chart any result in one click and pin it to a dashboard that refreshes itself.
Compare
Schemas between environments with the migration for the target, and table data with a sync script.
For DBAs too
Running queries and lock waits, cancel or end sessions, users & roles with their privileges.
Enterprise connections
SSH tunnels, SSL, read-only and production guard rails, SQL Server Windows authentication, Oracle without Instant Client.
Share with your team
Export connections without passwords, a data dictionary as one HTML page, and a Markdown knowledge base in Git.
Understand and redesign the model
Design on the live database
Edit tables, columns, keys and indexes right on the diagram. DB Mastermind writes the migration for your database, checks the existing data first and gives you the rollback script.
Models as text
Keep the model as a DBML file next to your notes, see the diagram as you type, and compare it with the database to get the migration.
AI that knows your database
Use your own API key (Anthropic, OpenAI, OpenRouter, Gemini, Azure, local Ollama) or your existing Claude Code / Codex subscription.
Ask, explain, fix
The assistant explores the schema, samples data, runs read-only queries and asks before any change. Press Ctrl/⌘ I in the editor to describe a query; failed statements get a Fix with AI button.
A per-database knowledge base of Markdown notes teaches it what your codes and statuses mean — and AI can write the first version for you.
Your databases in Claude Code, Codex and Cursor
DB Mastermind is also an MCP server: agents get schema exploration, read-only queries, join paths and your knowledge base, using the connections you already have.
claude mcp add dbmastermind -- "/Applications/DB Mastermind.app/Contents/MacOS/DB Mastermind" --mcp
Or just click Add to Claude Code / Claude Desktop / Codex / Cursor / VS Code in Settings → MCP server.
Pro kolegy: stáhněte si DB-Mastermind-…-win-x64-portable.zip, rozbalte a spusťte DB Mastermind.exe — nic se neinstaluje. V Nastavení → Obecné → Jazyk přepněte na češtinu. Připojení vám může kolega poslat jako soubor (bez hesel).
Code signing policy
Free code signing provided by SignPath.io, certificate by SignPath Foundation.
Team roles
- Committers and reviewers: Václav Mudra (@eLh0m3r0)
- Approvers: Václav Mudra (@eLh0m3r0)
How releases are built and signed
- Every release is built by GitHub Actions from the tagged source in this repository; nothing is built or signed on a personal computer.
- Only files built from this project's own source are signed. Contributions from outside the team are reviewed before they are merged.
- Each signing request is approved by hand by an approver.
- All team members use multi-factor authentication for GitHub and SignPath.
Installing and uninstalling
The portable zip changes nothing on your system: delete the folder to remove it (your data is in the data folder next to the app). The installers add a Start menu / Applications entry and remove it again through Apps & features on Windows, by moving the app to the Trash on macOS, with scoop uninstall db-mastermind or brew uninstall --cask db-mastermind, and on Linux by deleting the AppImage or removing the .deb package. Your settings and connections stay in your user data folder (Settings → About → Data folder) until you delete it.
Privacy
This program will not transfer any information to other networked systems unless specifically requested by the user or the person installing or operating it.
No telemetry, no analytics, no crash reports, no account. In detail:
- Update checks (the only thing that happens on its own): every few hours the app asks GitHub for the latest release and downloads it if there is one. GitHub sees your IP address and the app version, under the GitHub Privacy Statement. Turn it off in Settings → General → Updates; IT can turn it off for everyone with the
disableUpdateCheckpolicy. - Databases: the app connects only to the databases you set up.
- AI is off until you set up a provider. Then your questions and the schema and data the assistant reads go to the provider you chose, under its privacy policy: Anthropic, OpenAI, OpenRouter, Google Gemini, Azure OpenAI. Ollama runs on your own computer. Each connection can have AI turned off, and IT can turn it off for all.
- MCP server: off until you turn it on, and then it listens only on your own computer (127.0.0.1).
- Passwords and API keys are stored encrypted on your computer and never leave it, except to the database or AI provider they belong to.
This website is hosted on GitHub Pages; the download button asks GitHub which file is the latest.