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CanIUse MCP Server

CanIUse MCP - Browser Compatibility Intelligence

Installation

Add the following to your MCP client configuration file.

Configuration

{
  "mcpServers": {
    "amirmahdi-kaheh-caniuse-mcp": {
      "command": "caniuse-mcp-server",
      "args": [],
      "env": {
        "CANIUSE_OVERRIDES": "{\"css-variables\":\"supported\"}",
        "CANIUSE_POLYFILLS": "[\"css-variables\",\"promise-allsettled\"]",
        "CANIUSE_DEFAULT_BASELINE": "chrome-57"
      }
    }
  }
}

The CanIUse MCP Server delivers intelligent browser compatibility checks for your CSS and JavaScript, with configurable targets, polyfill awareness, project-wide scanning, and actionable remediation guidance. It helps you quickly assess what works across browsers, generate necessary configs, and streamline polyfill decisions so you can ship faster with confidence.

How to use

You use the server with MCP-compatible clients to scan your project, test specific features, and get concrete remediation steps. Start by running the MCP server locally, then configure your client to point at the server and invoke the analysis tools you need. You can scan entire projects, test particular features, and fetch suggested fixes or build configurations, all tailored to your chosen browser targets and polyfill strategy.

In practice, you typically set a baseline browser, optionally add polyfills, and then run analyses like a full project scan or feature checks. The results guide you toward precise fixes, polyfill installations, and configuration recommendations that align with your development workflow.

How to install

Prerequisites: you need Node.js (and npm) installed on your system. Ensure you’re using a supported Node version (Node.js 18+ is commonly required for MCP tooling). Then install the MCP server package globally or locally as shown.

Global installation (recommended) and immediate usage via MCP clients:

npm install -g caniuse-mcp-server

Local installation (for project-scoped usage):

npm install caniuse-mcp-server

Optionally, use the server through npx if a global install is not available or convenient:

npx caniuse-mcp-server

Configuration and usage notes

You configure the MCP client to connect to the server using one or more MCP endpoints. The following approaches are commonly used:

- Run the server as a local STDIO process with a straightforward command, e.g. caniuse-mcp-server or via npx caniuse-mcp-server, and keep the client pointing to that local process.

- If needed, specify the command and arguments explicitly in your MCP client configuration to ensure a consistent startup path across environments.

Examples and workflows

Basic project scan and baseline setup with defaults works well to start. You can then adjust the baseline browser, add polyfills, and request fixes or build configurations as your project requires.

Configuration and baseline updates can be applied through MCP client actions, including setting the baseline, adding polyfills, and adding custom browser targets.

Troubleshooting and tips

If you encounter issues starting or connecting to the MCP server, verify your Node version, ensure the MCP server package is installed, and check that your MCP client is configured to reference the correct command and arguments for starting the server.

For environment-based configuration, you can set defaults and polyfills via environment variables to ensure consistent behavior in CI/CD or local development.

Available tools

scan_project

Smart Project Analysis automatically detects compatibility issues across the project and reports a compatibility profile for the configured targets.

check_compatibility

Test specific features or files against configured browser targets to verify support.

get_fixes

Provide actionable remediation steps and polyfill recommendations for defined features.

generate_configs

Create complete toolchain configurations for your project, including Babel, PostCSS, Webpack, and CI setups.

manage_config

Manage baselines, polyfills, and custom browser targets through a unified configuration interface.