What is McpMux?
McpMux is a tray app for Windows, macOS and Linux that sits between your AI clients and your MCP servers. You install servers once, from a built-in registry of more than 100 or by hand, and point Cursor, Claude Code, VS Code, Windsurf, ChatGPT or any other MCP client at a single address, http://localhost:45818/mcp.
Credentials are stored in the operating system's keychain rather than plain-text JSON, sensitive database fields are encrypted with AES-256-GCM, and the gateway only listens on 127.0.0.1. Spaces separate sets of servers and credentials, such as work and personal; Feature Sets choose which tools, prompts and resources are exposed; and Workspaces map a project folder, reported by the client as its MCP root, to a Feature Set.
It is written in Rust with Tauri 2 and released under the GPL-3.0 licence.
Is McpMux worth it?
McpMux solves a dull problem properly. Anyone using two or three MCP clients keeps duplicate config files with the same tokens in plain text, and rotating a key means editing each one. McpMux replaces them with one local endpoint, moves secrets into DPAPI, Keychain or libsecret, and refreshes OAuth tokens in the background. Adding a server shows up in every connected client without a restart, according to the README.
The routing model is the interesting part. Because clients report the folder they are working in, McpMux can give a backend repository database and deploy tools while a docs folder sees only search and the file system. An optional @mux trigger lets the assistant search tools, compose a narrower Feature Set and pin it to the folder, with every change gated behind an approval dialog. That is a practical way to keep tool lists short, the same problem langgraph-bigtool attacks inside a single agent.
The project is small and moving fast. It has 26 stars, seven contributors and about 18,000 release downloads since it started in January 2026. The latest stable release, v0.7.0, came on 7 October 2026, followed by 17 pre-release builds in the next five days, and the app installs updates on launch by default. For a component that holds every credential your agents use, auto-update from a seven-person project is a trust decision worth making deliberately; the toggle is in Settings.
The GPL-3.0 licence matters only if you redistribute a modified build. Compared with ToolHive, which isolates each server in a container for teams, McpMux is a single-user convenience layer: it does not sandbox servers, it routes to them.
Where it earns its place
A freelance developer switching between Cursor and Claude Code
Stop pasting the same GitHub and Postgres tokens into two config files
Install both servers in McpMux, paste the one http://localhost:45818/mcp snippet into each client, and rotate keys in one place. Free.
A consultant with client and personal projects on one laptop
Make sure a personal side project can never reach a client's database
Create separate Spaces with their own credentials and map each project folder to its Space in Workspaces; matching is exact per folder.
A developer whose agent wastes tokens on dozens of tool definitions
Give each repository only the tools it needs
Ask '@mux build a minimal toolset for this repo and pin it to this folder' and approve the proposed Feature Set; later sessions in that folder get the smaller list.
Before you commit
- Setup
- Download from mcpmux.com, or curl -fsSL https://install.mcpmux.com | bash on Linux and brew install --cask mcpmux/tap/mcpmux on macOS; add servers, then paste one config block into each client.
- Integrations
- Cursor, VS Code with Copilot, Claude Code, Windsurf, ChatGPT and JetBrains IDEs by name, plus any MCP client over HTTP; stdio and remote servers upstream; OAuth 2.1 with PKCE for client approval.
- Data and privacy
- All traffic stays on the machine; secrets in the OS keychain, field-level AES-256-GCM encryption in SQLite, tokens kept out of logs. GPL-3.0.
- Limits
- Single machine, single user; servers run unsandboxed; frequent pre-release builds; 9 open issues.
What’s good
- One local MCP URL for every client
- Secrets in the OS keychain instead of plain-text JSON
- Per-folder toolsets through Workspaces and Feature Sets
- Registry of 100+ servers with one-click install
What’s not
- 26 stars and seven contributors behind a credential store
- Auto-updates on launch by default
- No sandboxing of the servers it launches
- Cloud sync of config is announced but not shipped
Best for
Developers who use several MCP clients on one machine and are tired of keeping their configs and keys in sync.
McpMux alternatives
McpMux: common questions
- Is McpMux worth it?
- A tidy answer to copying the same MCP config and API keys into four clients, still young enough that you should expect a new build most days. We rate it 3.6 out of 5.
- How much does McpMux cost?
- Free and open source under GPL-3.0; no paid plans published.
- What are the downsides of McpMux?
- 26 stars and seven contributors behind a credential store; auto-updates on launch by default; no sandboxing of the servers it launches; cloud sync of config is announced but not shipped.
- Who is McpMux best for?
- Developers who use several MCP clients on one machine and are tired of keeping their configs and keys in sync.
- Is McpMux safe for company data?
- All traffic stays on the machine; secrets in the OS keychain, field-level AES-256-GCM encryption in SQLite, tokens kept out of logs. GPL-3.0.
- What are the best McpMux alternatives?
- The closest alternatives we have reviewed are ToolHive, Bifrost and LiteLLM.
Answers checked Nov 3, 2026.