How to Use the JWT & Base64 Decoder MCP in Claude

Q: How do I install the JWT & Base64 Decoder in Claude Desktop?

Add the MCP server command to your claudedesktopconfig.json file. Save the file and restart the application to see the new tools.

Stop hallucinating token data. Decode JWTs and Base64 strings deterministically right inside Claude Desktop.

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Connect JWT & Base64 Decoder MCP to Claude Desktop

Create your Vinkius account to connect JWT & Base64 Decoder to Claude Desktop and route execution through our secure gateway. The platform manages server hosting, runtime updates, and security layers. Configuration requires no manual server provisioning.

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Setup JWT & Base64 Decoder with Claude Desktop

Ask AI about this MCP

ChatGPT

Claude

Perplexity

Parse Tokens in Claude Desktop

The `decode_jwt_token` tool pulls apart JSON Web Tokens to expose the exact header and payload data. You paste a token into your chat, and the agent reads the raw claims without guessing. It calculates the exact expiration date automatically. You avoid converting epoch timestamps manually or worrying about language model math errors causing security misconfigurations.

Deterministic Base64 Translation

The `decode_base64_string` tool converts raw Base64 strings into readable UTF-8 text. Language models struggle with byte-level conversions, often returning close but incorrect strings. This tool forces the agent to use deterministic standard libraries instead of probabilistic generation. You get the exact decoded string back every time you ask for a translation.

Inspect Without Verifying

These tools inspect payloads but they do not verify cryptographic signatures. You use this MCP server to read claims and headers during local development or debugging. Never assume a token is valid just because it decoded successfully. The agent will show you the exact contents of the token so you can fix your auth flow before testing actual signature validation.

Setup guide

Set up JWT & Base64 Decoder MCP in Claude Web or Desktop

1

Open Claude Settings

Go to claude.ai, click your profile icon, then navigate to Customize → Connectors.
2

Add Custom Connector

Click the "+" button and select Add custom connector. Paste your Vinkius endpoint URL: https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp Replace [YOUR_TOKEN_HERE] with your token from cloud.vinkius.com. For OAuth-protected servers, expand Advanced settings to add credentials.
3

Start a conversation

Open a new chat. The JWT & Base64 Decoder MCP tools are available immediately — no restart needed.

Endpoint URL

https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp

No configuration file needed — paste the URL directly in the Claude web interface.

Available on Free (1 connector), Pro, Max, Team, and Enterprise plans.

Prerequisites

Claude Desktop installed (macOS or Windows)
Active Vinkius subscription with a valid endpoint token

1

Open Claude Desktop Settings

Click the menu icon at the top-left corner, go to Settings → Developer → Edit Config. This opens claude_desktop_config.json in your default text editor.
2

Paste the JWT & Base64 Decoder MCP configuration

Copy the JSON snippet on the right into the mcpServers object. Replace [YOUR_TOKEN_HERE] with your endpoint token from cloud.vinkius.com.
3

Restart Claude Desktop

Close and reopen the application. Claude needs a full restart to load new MCPs — refreshing a conversation is not enough.
4

Verify the connection

Open a new conversation. Click the 🔌 icon at the bottom of the message input. You should see tools listed under jwt-base64-decoder-mcp.

json

{
  "mcpServers": {
    "jwt-base64-decoder-mcp": {
      "url": "https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp"
    }
  }
}

Get your connection token →

Independent Platform Disclaimer: Vinkius is an independent platform and is not affiliated with, endorsed by, sponsored by, verified by, or otherwise authorized by JWT Decoder. All third-party trademarks, logos, and brand names are the property of their respective owners. Their use on this website is strictly for informational purposes to identify service compatibility and interoperability.

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Common questions about JWT & Base64 Decoder MCP in Claude Desktop

Add the MCP server command to your claude_desktop_config.json file. Save the file and restart the application to see the new tools.

Yes, you can connect it via Settings and Integrations. You just paste the remote MCP server URL and authenticate.

Pasting tokens into random websites is a massive security risk. This keeps your auth debugging inside your established local environment.

No, it only decodes the payload and headers. You still need to validate the cryptographic signature in your actual backend code.

The MCP server processes raw Base64 strings and JSON Web Tokens locally or via your configured endpoint. It reads specific claims and headers, meaning those plaintext values enter your chat history. Do not paste live production tokens containing sensitive PII.

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