> This page is for Documentation, version Refactor guides.
> For other versions, use one of these documentation indexes:
> - Integration guides (default): https://avalara.ferndocs.com/docs/integration-guides/llms.txt
> - Refactor guides: https://avalara.ferndocs.com/docs/refactor-guides/llms.txt
> - Get certified: https://avalara.ferndocs.com/docs/get-certified/llms.txt
> - Agent to Agent (A2A): https://avalara.ferndocs.com/docs/agent-to-agent-a2a/llms.txt
> - AI use cases: https://avalara.ferndocs.com/docs/ai-use-cases/llms.txt
> - API versioning: https://avalara.ferndocs.com/docs/api-versioning/llms.txt

> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://avalara.ferndocs.com/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://avalara.ferndocs.com/_mcp/server.

# AvaTax Refactor Guides

In 2004, Avalara built AvaTax using SOAP. In 2016, Avalara built a completely new REST API that works off the same code and data while adopting modern standards (OpenAPI/Swagger and Microsoft's REST guidelines). Whether you have a SOAP or RESTv1 integration, these refactor guides tell you how to bring your integration up to date with the latest version of the AvaTax APIs.

#### [SOAP To RESTV2 Refactor Guide](/docs/refactor-guides/ava-tax-refactor-guides/soap-to-restv2/get-started)

To bring your integration up to date with the latest version of the AvaTax APIs, use this document to refactor your APIs from AvaTax SOAP to AvaTax RESTv2.

#### [RESTV1 To RESTV2 Refactor Guide](/docs/refactor-guides/ava-tax-refactor-guides/restv1-to-restv2/get-started)

To bring your integration up to date with the latest version of the AvaTax APIs, use this document to refactor your APIs from AvaTax RESTv1 to AvaTax RESTv2.