SandboxAPI

What SandboxAPI MCP server does

SandboxAPI MCP server exposes remote code execution through the Model Context Protocol. An MCP-compatible client can submit source code, select a language, optionally provide standard input, and receive the execution result. The supported languages are Python 3.12, JavaScript on Node 22, TypeScript 5.4, Go 1.22, Java 21, C++ with GCC 14, C with GCC 14, and Bash 5.2.

The service is intended for short-lived execution rather than persistent development environments. Each run occurs in a separate container. Containers are destroyed after execution, and writes do not persist between runs.

How it works

The client connects to the hosted MCP endpoint at https://mcp.sandboxapi.dev/mcp, or to a locally run instance. The server forwards execution requests to the SandboxAPI backend, which runs them in Docker containers using gVisor. A user API key is required for the backend. The MCP endpoint can also be protected with a separate optional authentication key.

Network access is disabled for executed programs. The environment applies CPU, memory, disk, and timeout restrictions, and uses a read-only filesystem. Submitted source code is limited to 1 MB. The default execution timeout is 10 seconds, with a maximum of 300 seconds.

A batch request contains multiple execution objects. SandboxAPI MCP server runs each object in its own isolated sandbox, rather than sharing state between snippets.

Setup and configuration

The hosted option requires no local installation. Configure the client with the MCP URL and an Authorization: Bearer ... header containing a SandboxAPI key. The README provides configurations for Claude Desktop, Cursor, and VS Code; it also identifies Windsurf as an MCP-compatible client.

For local deployment, the project can be started with the published Docker image sandboxapi/mcp:latest, or compiled from the Go source repository. A local instance listens on port 8081 by default and exposes the /mcp path. Set MCP_PORT to change the port.

Required configuration includes SANDBOXAPI_API_KEY. SANDBOXAPI_URL can override the default backend URL. MCP_API_KEY is optional and adds authentication for the MCP endpoint; omitting it leaves that endpoint open according to the README.

Tools and capabilities

• execute_code accepts a language, source code, optional timeout, and optional standard input.
• execute_batch accepts an array of executions, each with its own language, code, timeout, and input settings.
• list_languages returns supported languages, versions, aliases, and example code without requiring parameters.

Language aliases include python, py, js, node, ts, golang, jdk, c++, gcc, sh, and shell.

Limitations and notes

SandboxAPI MCP server does not provide outbound network access from executed code. Files are temporary, and the filesystem is read-only, so it is not suitable for workflows that require persistent artifacts or network-dependent packages. Runtime limits also make it unsuitable for unrestricted long-running processes. API access requires a key obtained through SandboxAPI or its listed RapidAPI offering. The repository is licensed under MIT.