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How to connect Taxjar to Claude

Connect Claude Web, Desktop and Cowork to Taxjar MCP. Calculate sales tax for a new order, list all order transactions this month, and more using natural language, with authentication handled for you.

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TaxJar is a trusted sales tax automation platform for ecommerce and SaaS businesses. It delivers real-time tax calculations, accurate reporting, and seamless filing across all US states.

21 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 Taxjar account to Claude via Composio Connect, enabling it to calculate sales tax for a new order, list all order transactions this month, show your current nexus regions, 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 Taxjar with

OpenAI Agents SDKClaude Agent SDKClaude CodeCodexOpenClawHermesAtomic AgentGoogle ADKLangChainVercel AI SDKMastra AILlamaIndexCrewAIPydantic AIAutoGen

Connecting Taxjar 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 Taxjar account

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

For example, ask Claude to:

  • "Calculate sales tax for a new order"
  • "List all order transactions this month"
  • "Show your current nexus regions"

It will prompt you to authenticate and authorize access.

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

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

The Taxjar MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Taxjar account. It provides structured and secure access to your sales tax data, so your agent can perform actions like calculating sales tax, managing transactions, listing customers, and monitoring nexus regions on your behalf.

  • Real-time tax calculation for orders: Instantly calculate accurate sales tax for new orders, factoring in nexus addresses, line items, shipping, and exemptions.
  • Order and refund transaction management: Let your agent create, list, or delete order and refund transactions to streamline your sales and returns workflow.
  • Customer database access: Effortlessly retrieve, list, or delete customer records for tax reporting and compliance purposes.
  • Nexus region insights: Quickly identify and list all nexus regions where your business has sales tax obligations.
  • Automated transaction reporting: Access up-to-date lists of transactions and refunds for reconciliation, filing, and audit readiness.

Troubleshooting

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

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

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

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

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

  • 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 Taxjar.
  • If it fails again, send the error and the ofid_ reference id to support@composio.dev.

3. Why does the Taxjar authorization link not work?

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

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

4. Why do Taxjar actions fail after they worked before?

The Taxjar connection can expire or lose permission.

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

5. How do I switch to a different Taxjar account?

Claude can manage the Taxjar connection for you.

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

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

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

  • In Claude Desktop, open Customize > Connectors.
  • Next to Composio, click ⋮ and click Clear cache.
  • If Taxjar 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 Taxjar.
TOOLS

Supported Tools

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

Calculate Sales Tax For An Order

Tool to calculate sales tax for an order.

Create Customer

Tool to create a new customer with exemption information.

Create Order Transaction

Creates a new order transaction in TaxJar for sales tax reporting and compliance.

Create Refund Transaction

Tool to create a new refund transaction.

Delete Customer

Tool to delete an existing customer.

Delete Order Transaction

Tool to delete an existing order transaction.

Delete Refund Transaction

Tool to delete an existing refund transaction.

List Customers

Lists all customer IDs from your TaxJar account.

List Nexus Regions

Tool to list existing nexus regions for an account.

List Order Transactions

List order transaction IDs within a date range.

List refund transactions

Lists refund transaction IDs within a specified date range.

List Tax Categories

Tool to list all product tax categories and their codes.

Show Customer

Tool to show an existing customer.

Show Order Transaction

Tool to show an existing order transaction by ID.

Show Refund Transaction

Retrieves detailed information about a specific refund transaction from TaxJar.

Show Tax Rates for a Location

Tool to show sales tax rates for a location.

Summarize Tax Rates for All Regions

Tool to retrieve minimum and average sales tax rates by region.

Update Customer

Tool to update an existing customer in TaxJar.

Update Order Transaction

Tool to update an existing order transaction.

Update Refund Transaction

Tool to update an existing refund transaction.

Validate VAT Number

Validates EU VAT identification numbers against the VIES (VAT Information Exchange System) database.

FRAMEWORKS

How to build Taxjar MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Taxjar MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Taxjar MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Taxjar MCP with Claude Code

Codex logo

Codex

Use Taxjar MCP with Codex

OpenClaw logo

OpenClaw

Use Taxjar MCP with OpenClaw

Hermes logo

Hermes

Use Taxjar MCP with Hermes

Atomic Agent logo

Atomic Agent

Use Taxjar MCP with Atomic Agent

Google ADK logo

Google ADK

Use Taxjar MCP with Google ADK

LangChain logo

LangChain

Use Taxjar MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Taxjar MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Taxjar MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Taxjar MCP with LlamaIndex

CrewAI logo

CrewAI

Use Taxjar MCP with CrewAI

Pydantic AI logo

Pydantic AI

Use Taxjar MCP with Pydantic AI

AutoGen logo

AutoGen

Use Taxjar MCP with AutoGen

FAQ

Frequently asked questions

With a standalone Taxjar MCP server, the agents and LLMs can only access a fixed set of Taxjar tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Taxjar 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 Taxjar tools.

Yes, absolutely. You can configure which Taxjar 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 Taxjar data and credentials are handled as safely as possible.

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