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How to connect 44API to Claude

Connect Claude Web, Desktop and Cowork to 44API MCP. Validate a customer's eu vat number, look up company details by tax id, and more using natural language, with authentication handled for you.

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44API is an API service for validating VAT and tax identifiers and returning company details. Use it to verify business tax data and manage account IP whitelists quickly.

4 Tools

Introduction

Claude is Anthropic's AI assistant, available on the web, in the desktop app, and on mobile. Cowork is its agent for knowledge work, and it runs on all of those surfaces too. Connected to your apps, Claude can work with your files and services to accomplish complex tasks on your behalf.

This guide walks you through the easiest and most secure way to connect your 44API account to Claude via Composio Connect, enabling it to validate a customer's EU VAT number, look up company details by tax ID, add office IP to 44API whitelist, and more such actions on your behalf without compromising your account security.

Setup is the same on Claude Web, Desktop, and Cowork, and you only need to do it once. The connector is tied to your account, so it's available in all three.

Also integrate 44API with

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Connecting 44API to Claude Web, Desktop, and Cowork

Two ways to add the Composio connector. Pick whichever you prefer.

1. Add with one click

Click the button. Claude opens with the Composio connector filled in. Click Add, then go to step 2.

Add to Claude

Add manually

In Claude Desktop, click Customize in the left sidebar, then select Connectors and click the + icon at the top.

Claude Desktop connectors screen with Add custom connector selected

Click Add custom connector and paste in the Composio MCP server URL:

bash
https://connect.composio.dev/mcp
Add custom connector dialog with Composio MCP server URL

2. Authorize in your browser

Click Connect. You'll be redirected to a browser window where you can authorize Composio to continue.

Composio authorization screen for Claude Web, Desktop, and Cowork

3. Connect your 44API account

Back in Claude, ask it to connect to 44API or give it any 44API-related task.

For example, ask Claude to:

  • "Validate a customer's EU VAT number"
  • "Look up company details by tax ID"
  • "Add office IP to 44API whitelist"

It will prompt you to authenticate and authorize access.

That's it. Composio's tools are now available in Claude, and your 44API account is ready to use.

What is the 44API Claude Connector, and what's possible with it?

The 44API MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your 44API account. It provides structured and secure access so your agent can perform 44API operations on your behalf.

Troubleshooting

1. Why does Claude not use the Composio connector for 44API?

The connector can show as connected, but Claude must use it in each 44API conversation.

  • Click + at the lower left of the chat, or type /.
  • Hover Connectors.
  • Turn on Composio.
  • Ask Claude to connect to 44API again.

2. Why does Claude show an MCP server error before 44API connects?

Claude can show Couldn't reach the MCP server or Authorization with the MCP server failed when you add the connector for 44API.

  • Check that the connector URL is https://connect.composio.dev/mcp.
  • Connectors run from Anthropic's cloud, so your device network is usually not the problem.
  • Add the connector again from Customize > Connectors, then ask Claude to connect 44API.
  • If it fails again, send the error and the ofid_ reference id to support@composio.dev.

3. Why does the 44API authorization link not work?

The Composio connector is one server. Your 44API account connects separately when Claude asks for it.

  • If the browser does not open, or the link expires, ask Claude to retry the 44API connection.
  • Composio creates a fresh 44API authorization link.
  • Open that link in your browser and finish the 44API sign-in.

4. Why do 44API actions fail after they worked before?

The 44API connection can expire or lose permission.

  • Ask Claude to inspect the 44API connection.
  • If the connection is unhealthy, disconnect it when Claude prompts you.
  • Reconnect the 44API account and retry the action.
  • If Claude shows a permission prompt, approve it before Claude changes data in 44API.
  • If the action still fails with a permission error, check that the connected account has that permission in 44API itself.

5. How do I switch to a different 44API account?

Claude can manage the 44API connection for you.

  • Ask Claude to disconnect or delete the current 44API account.
  • Ask Claude to connect 44API again.
  • Open the new Composio authorization link for 44API.
  • Sign in with the other 44API account in the browser.
  • After the account connects, ask Claude to retry the 44API task.

6. Why is my 44API connection missing in Claude Desktop or on a Team plan?

The connector belongs to your Claude account, so your 44API connection works in Claude Web, Desktop, and Cowork.

  • In Claude Desktop, open Customize > Connectors.
  • Next to Composio, click ⋮ and click Clear cache.
  • If 44API tools still do not appear, click ⋮, disconnect, remove the connector, and add it again.
  • On Team or Enterprise, an Owner or Primary Owner must enable the connector before you can connect 44API.
TOOLS

Supported Tools

Every 44API action and event your agent gets out of the box.

Add Whitelisted IP

Add one IPv4 or IPv6 address to the account whitelist using a verification email address.

List Whitelisted IPs

List IP addresses currently allowed by the account whitelist.

Remove Whitelisted IP

Remove one IPv4 or IPv6 address from the account whitelist.

Validate VAT Number

Validate one VAT or tax ID for a supported country and return its validity plus any company details available on the connected plan.

FRAMEWORKS

How to build 44API MCP Agent with another framework

ChatGPT logo

ChatGPT

Use 44API MCP with ChatGPT

Hermes logo

Hermes

Use 44API MCP with Hermes

Atomic Agent logo

Atomic Agent

Use 44API MCP with Atomic Agent

FAQ

Frequently asked questions

With a standalone 44API MCP server, the agents and LLMs can only access a fixed set of 44API tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from 44API and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Claude Cowork fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right 44API tools.

Yes, absolutely. You can configure which 44API scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your 44API data and credentials are handled as safely as possible.

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