Medusa Avalara Plugin

A Medusa plugin for integrating Avalara AvaTax as a tax provider, enabling automated tax calculations and compliance for your e-commerce store. Created and maintained by u11d.

Table of Contents

• Features
• Quick Start
• Configuration Options
• Advanced Usage
• How the plugin works?
• Troubleshooting
• Need help?
• Contributing
• License

Features

• Real-time Tax Calculations: Automatically calculate accurate taxes during checkout using Avalara's AvaTax API
• Order Transaction Management: Create AvaTax transactions when orders are placed for proper tax recording
• Transaction Lifecycle Tracking:
  • Commit transactions when orders are completed/fulfilled
  • Void transactions when orders are canceled
• Flexible Configuration: Support for custom tax codes, exemptions (entity use code) and shipping addresses.
• Address Validation: Validate and standardize shipping addresses using Avalara's address validation service

Quick Start

1. Installation

# npm
npm install @u11d/medusa-avalara
# yarn
yarn add @u11d/medusa-avalara

2. Basic Medusa Config

Add the plugin to your Medusa config file (medusa-config.ts) using the withAvalaraPlugin helper:

import { defineConfig } from "@medusajs/framework/utils";
import { withAvalaraPlugin, AvalaraPluginOptions } from "@u11d/medusa-avalara";

const avalaraPluginOptions: AvalaraPluginOptions = {
  accountId: 0, // Your Avalara account ID
  licenseKey: "YOUR_LICENSE_KEY",
  environment: "sandbox",
  companyId: 0, // Your Avalara company ID
  companyCode: "DEFAULT",
  defaultTaxCode: "PC040100", // Clothing and related products (business-to-customer)-general
};

module.exports = defineConfig(
  withAvalaraPlugin(
    {
      projectConfig: {
        // your project config
      },
      plugins: [
        // other plugins
      ],
      modules: [
        // your modules
      ],
    },
    avalaraPluginOptions
  )
);

Recommended Checkout Workflow

For accurate tax calculations and optimal API efficiency, we recommend the following checkout workflow:

1. Customer enters shipping address - Address is captured but taxes are not yet calculated
2. Customer selects shipping method - Shipping option is chosen
3. Trigger tax calculation - Storefront calls POST /store/carts/{id}/taxes (API docs) to calculate accurate taxes with complete cart information
4. Customer reviews order - Final amounts including taxes are displayed
5. Complete checkout - Order is placed with correct tax calculations

Why this workflow? The plugin operates as a tax provider within Medusa's framework and is invoked whenever Medusa triggers tax calculations. The plugin cannot modify Medusa's core checkout flow or enforce when taxes are calculated. By following this workflow and disabling "Automatic Taxes" in your region settings, you control exactly when tax calculations occur, ensuring they happen only after all necessary information (address and shipping method) is available.

Important Notes:

• Automatic Taxes Setting: The region's Automatic Taxes configuration significantly impacts API efficiency. When enabled, Medusa automatically calls the tax provider multiple times during checkout (on address changes, shipping method selection, etc.), increasing Avalara API requests. For better performance and cost control, disable automatic taxes and manually trigger calculations via POST /store/carts/{id}/taxes after the shipping method is selected.
• Tax Recalculation: Medusa doesn't automatically recalculate taxes when cart properties change (quantity, address, discounts). Always call POST /store/carts/${cartId}/taxes before checkout to ensure accurate amounts. See issue #13929
• The withAvalaraPlugin wrapper handles plugin modules registration and dependency injection automatically. See Manual Module Registration section if you need to understand what the helper does or configure modules manually
• You can use environment variables instead of hardcoding options, especially important for credentials like accountId and licenseKey
• The example above will use PC040100 for each product. See Advanced Usage for assigning specific tax codes to individual products
• The plugin automatically syncs your Medusa stock locations with Avalara locations on startup for accurate tax calculations. However, since Medusa doesn't emit events for stock location changes, if you create or update a location after startup, you'll need to either restart the app or manually call POST /admin/avalara-cache/feed to refresh the cache
• The plugin fully supports tax-inclusive pricing and automatically respects the region's tax-inclusive preferences
• Discounts should be used with caution. Medusa does not use the exact tax amounts returned by Avalara but instead calculates taxes using the rates provided, which may lead to minor differences in final tax calculations when discounts are applied.

3. Run Database Migration

After configuring your Medusa setup, run the database migration to create the required tables:

npx medusa db:migrate

4. Enable AvaTax Provider

After starting your Medusa server:

1. Go to your admin panel (locally available at http://localhost:9000/app by default)
2. Navigate to Settings > Tax Regions
3. Select a tax region and edit it
4. Select Avalara as your tax provider
5. Save the configuration

Note: To disable Avalara and return to the default Medusa tax calculations, simply select System as your tax provider in the same settings.

Configuration Options

Access your Avalara dashboard to obtain the required credentials:

• Production: https://admin.avalara.com/
• Sandbox: https://sandbox.admin.avalara.com/

Option	Type	Required	Default	Description
accountId	number	✅	-	Your Avalara account ID
licenseKey	string	✅	-	Your Avalara license key
environment	"sandbox" | "production"	✅	-	AvaTax environment
companyCode	string	✅	-	Your company code in AvaTax
companyId	number	✅	-	Your Avalara company ID
documentRecordingEnabled	boolean	❌	true	Controls whether documents should be recorded in AvaTax. If set to false transactions (sales invoices) are not created
machineName	string	❌	-	Machine identifier
defaultTaxCode	string	❌	-	Default tax code for products
shippingTaxCode	string	❌	"FR020100"	Tax code for shipping

Advanced Usage

Authentication for Admin API Endpoints

The configuration endpoints for managing product tax codes and customer exemptions require admin credentials. You'll need to authenticate first to get a Bearer token that you'll use for subsequent API requests.

Get Authentication Token:

curl -X POST http://localhost:9000/auth/user/emailpass \
  -H "Content-Type: application/json" \
  -d '{
    "email": "your_admin_email@example.com",
    "password": "your_admin_password"
  }'

This will return a response containing a token field. Copy this token value to use in the Authorization: Bearer YOUR_TOKEN_HERE header for the admin API endpoints described below.

Using Different Tax Codes for Products

In most e-commerce scenarios, different products require different tax codes based on their category, material, or intended use. The plugin uses the avalara_product table to determine which specific Avalara tax code should be applied to each product during tax calculations. You can manage these product-specific tax codes either by updating the database table directly or by using the provided admin API endpoint.

You can find the complete list of available Avalara tax codes at: https://taxcode.avatax.avalara.com/

By default, all products will use the taxCodes.default value. To assign specific Avalara tax codes to individual products, make a PUT request to /admin/avalara-products using your authentication token:

Update Product Tax Codes:

curl -X PUT http://localhost:9000/admin/avalara-products \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_TOKEN_HERE" \
  -d '{
    "avalara_products": [
      {
        "product_id": "prod_123",
        "tax_code": "PC040100"
      },
      {
        "product_id": "prod_456",
        "tax_code": "PS081000"
      }
    ]
  }'

Customer Tax Exemptions (Entity Use Codes)

Many businesses need to support tax-exempt customers such as government entities, non-profit organizations, or resellers. The plugin provides a complete system for managing customer exemptions using Avalara's Entity Use Codes.

For the complete list of predefined entity use codes, refer to the official Avalara documentation.

Managing Customer Exemptions

The plugin manages customer exemptions through the avalara_customer module, which stores entity use codes for exempt customers and caches them for fast lookup during tax calculations.

Setting Customer Exemptions:

curl -X PUT http://localhost:9000/admin/avalara-customers \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_TOKEN_HERE" \
  -d '{
    "avalara_customers": [
      {
        "customer_id": "cus_federal_agency",
        "entity_use_code": "A"
      },
      {
        "customer_id": "cus_nonprofit",
        "entity_use_code": "E"
      }
    ]
  }'

Listing Customer Exemptions:

curl -X GET "http://localhost:9000/admin/avalara-customers?offset=0&limit=20" \
  -H "Authorization: Bearer YOUR_TOKEN_HERE"

Address Validation

The plugin provides a POST /store/avalara-address endpoint that serves as a proxy to Avalara's ResolveAddressPost API. Address validation is critical for accurate tax calculations, as Avalara requires correctly formatted and validated addresses to determine proper tax rates and jurisdictions.

Request Body:

{
  "line1": "512 S Mangum St Ste 100",
  "city": "Durham",
  "region": "NC",
  "postalCode": "27701",
  "country": "US"
}

Notes:

• Address validation is available for US and Canadian addresses
• Use this endpoint in your storefront during checkout to validate and save corrected addresses before tax calculation
• The response includes validated addresses, coordinates, resolution quality, and tax authorities
• Refer to Avalara's API documentation for more details: https://developer.avalara.com/api-reference/avatax/rest/v2/methods/Addresses/ResolveAddressPost/

Manual Module Registration

If you prefer to configure modules manually without using the withAvalaraPlugin wrapper, you can register each module individually:

import { defineConfig, Modules } from "@medusajs/framework/utils";
import { AvalaraPluginOptions } from "@u11d/medusa-avalara";

const options: AvalaraPluginOptions = {
  // your options here
};

module.exports = defineConfig({
  plugins: ["@u11d/medusa-avalara"],
  modules: [
    {
      resolve: "@u11d/medusa-avalara/modules/avalara-product",
      dependencies: [Modules.CACHE],
    },
    {
      resolve: "@u11d/medusa-avalara/modules/avalara-customer",
      dependencies: [Modules.CACHE],
    },
    {
      resolve: "@u11d/medusa-avalara/modules/avatax-factory",
      options,
      dependencies: [Modules.CACHE],
    },
    {
      resolve: "@medusajs/medusa/tax",
      options: {
        providers: [
          {
            resolve: "@u11d/medusa-avalara/providers/avatax",
            options,
          },
        ],
      },
      dependencies: [Modules.CACHE],
    },
  ],
});

Note: Manual registration requires careful attention to module dependencies and isolation. The withAvalaraPlugin wrapper is recommended as it handles these complexities automatically.

How the plugin works?

The Medusa Avalara plugin integrates with Avalara's AvaTax service through a modular architecture:

Core Components

modules/avalara-product

• Manages product-specific tax codes through the AvalaraProduct model and database migration
• Used by the /admin/avalara-products API endpoint
• Saves mapping of product_id → avalara_tax_code in cache for fast retrieval by the AvaTax provider

modules/avalara-customer

• Manages customer-specific tax exemptions through the AvalaraCustomer model and database migration
• Used by the /admin/avalara-customers API endpoint
• Saves mapping of customer_id → entity_use_code in cache for fast retrieval by the AvaTax provider
• Validates entity use codes against Avalara's predefined list and provides warnings for unrecognized codes

modules/avatax-factory

• Provides AvaTax client configured with plugin options
• Validates plugin options and credentials
• Validates communication with Avalara to ensure credentials are correct (validation happens in loader)

providers/avatax

• Tax calculation provider implementation (separate from avatax-factory due to Medusa's module isolation requirements)
• Skips tax calculation if shipping address is not provided
• Retrieves avalara_tax_code from cache; uses default tax code or throws error if not found
• Makes API calls to AvaTax to create SalesOrder entities (temporary entities for dynamic cart tax calculations)
• The getTaxLines method handles tax rate calculations using the AvaTax API

Order Lifecycle Integration

Subscribers and Workflows:

• orderPlacedHandler: Creates Sales Invoices (permanent entities representing finalized transactions in Avalara)
• orderCanceledHandler: Voids the transaction in Avalara
• orderCompletedHandler: Commits the transaction in Avalara

Important Note on Voiding Transactions: A document can be voided only if it has not yet been locked or reported in a tax filing period. Once a document has been reported (filed) or the filing period is locked, it cannot be voided directly through the API. In such case the plugin will log an error and you must create an adjustment (return invoice) manually in Avalara to offset the original document.

This architecture ensures accurate tax calculations during checkout and proper transaction lifecycle management in Avalara's system. The withAvalaraPlugin wrapper simplifies the setup by automatically configuring all these modules with proper dependencies and isolation.

Cached Data

The plugin uses Redis cache to store frequently accessed data for optimal performance during tax calculations. This cache strategy minimizes database queries and API calls, ensuring fast response times during checkout.

Product Tax Codes (avalara:product:{product_id})

• Stores the mapping of Medusa product IDs to Avalara tax codes
• Fed by the feed-avalara-product-cache workflow step
• Retrieved during tax calculations to determine the appropriate tax code for each line item
• Falls back to taxCodes.default if no product-specific code is found

Customer Exemptions (avalara:customer:{customer_id})

• Stores entity use codes for tax-exempt customers
• Fed by the feed-avalara-customer-cache workflow step
• Retrieved during tax calculations to apply exemptions when applicable
• Enables quick lookup of customer tax exemption status without database queries

Tax-Inclusive Settings (avalara:tax_included:{country_code})

• Stores whether prices are tax-inclusive for each country
• Fed by the feed-avalara-tax-inclusive-cache workflow step
• Based on region price preferences configured in Medusa
• Critical for correctly calculating taxes in regions with tax-inclusive pricing

Location Mappings (avalara:location:{country_code} and avalara:location:{country_code}_{province_code})

• Stores the mapping of geographic locations to Avalara location codes and addresses
• Fed by the feed-avalara-location-cache workflow step
• Syncs Medusa stock locations with Avalara locations for accurate origin-based tax calculations
• Supports both country-level and province/state-level location mappings for precise nexus determination

Cache Management:

• All cache entries use a 30-day TTL (Time To Live)
• The cache is automatically populated on application startup through the init-feed-avalara-cache job
• The cache is automatically refreshed every night at midnight via the feed-avalara-cache scheduled job
• Cache can be manually refreshed anytime via the POST /admin/avalara-cache/feed endpoint
• Individual module caches are also refreshed after bulk updates via their respective admin endpoints (e.g., after updating product tax codes or customer exemptions)

Troubleshooting

Migration Error: "relation ... does not exist"

If you encounter any of the following errors:

error: Failed to feed cache. Error: select "a0".* from "public"."avalara_product" as "a0" where "a0"."deleted_at" is null order by "a0"."created_at" desc limit 1000 - relation "public.avalara_product" does not exist. Please make sure migration adding avalara_product table has been run and cache module is injected to the module via medusa-config

Failed to feed cache. Error: select "a0".* from "public"."avalara_customer" as "a0" where "a0"."deleted_at" is null order by "a0"."created_at" desc limit 1000 - relation "public.avalara_customer" does not exist. Please make sure migration adding avalara_customer table has been run and cache module is injected to the module via medusa-config.

Solution: Run the database migration:

npx medusa db:migrate

This ensures the avalara_product table is created and the cache module is properly configured.

Tax calculations returning $0

If you're seeing $0 tax amounts in your calculations, follow these troubleshooting steps:

1. Check application logs for any error messages or warnings related to AvaTax API calls
2. Verify shipping address - tax calculation is skipped if no valid shipping address is provided
3. Validate Avalara account configuration:
   • Ensure your company location is properly configured in your Avalara account
   • Verify that tax jurisdictions are set up correctly for your business locations
   • Check that your company has nexus configured for the relevant states/regions
4. Test tax calculation directly in Avalara:
   • Log into your Avalara account
   • Use the AvaTax API testing tools to verify tax calculations work with your setup
   • Test with the same addresses and product codes you're using in Medusa
5. Review tax codes:
   • Ensure products have valid Avalara tax codes assigned
   • Verify that the tax codes are appropriate for your products and jurisdiction
6. Check environment settings:
   • Confirm you're using the correct environment (sandbox vs production)
   • Verify your API credentials are valid and have the necessary permissions

Need help?

If you encounter any issues or need assistance with this plugin, please visit our GitHub Issues page. Our team actively monitors and responds to bug reports, feature requests, and questions from the community. We aim to provide timely support to ensure your integration with Avalara runs smoothly.

Need expert assistance or want our team to support your Medusa project? We're here to help! Contact us at https://u11d.com/contact/ for professional support and consultation services.

Learn More

Read our comprehensive blog article about integrating Avalara with Medusa: https://u11d.com/blog/automated-tax-calculations-medusa-avalara-integration

Contributing

We welcome contributions! Please see our Contributing Guide for details.

License

This project is licensed under the MIT License - see the LICENSE file for details.