About the O Series Tax Calculation API

Vertex® O Series web services via the Tax Calculation and Tax GIS API allow you to integrate O Series with your financial host system using REST requests and responses. There are requests for each type of financial event that you can process in O Series for both Sales and Procurement perspectives.

Use the Tax Calculation and Tax GIS API to:

Perform Calculation calls on Sales transactions, including: Quotations, Invoices, and Distribute Tax calls
Perform Calculation calls on Procurement transactions, including: Accruals, Invoices, Distribute Tax calls, and Evaluated Receipts Settlement (ERS) calls
Perform Calculation calls on Owner transactions, including: Inventory Removal and Asset Movement.

Tax Calculation OAS file

See OAS - Tax Calculation and Tax GIS API to download the OpenAPI Specification (OAS) file for the O Series Tax Calculation API.

How O Series calculates tax

The Calculation service calculates tax, based on the financial event of the transaction, the tax jurisdictions identified in the transaction, and the tax situs. The Vertex Calculation Engine uses the tax rates and rules that are associated with these jurisdictions to determine the tax conclusion and to calculate a tax amount, and that information is included in the response.

O Series receives the transaction request message from the host financial system through an external interface.
TaxGIS identifies the tax jurisdictions for the transaction by using Tax Area IDs that are stored in the TaxGIS database.
The Calculation Engine determines the jurisdiction with tax situs or place of supply.
The Calculation Engine determines the tax conclusion and generates a response message.
O Series writes the transaction results to the Tax Journal, as appropriate for the financial event.
The financial system retrieves the transaction response message from O Series via the external interface.

Here's the flow of a transaction through the system:

About the O Series Transaction Management API

The Transaction Management in O series through the Tax Calculation and Tax GIS API contains requests for interacting with transactions once calculation has already occurred.

Use the Tax Calculation and Tax GIS API to:

Make Delete calls to delete a transaction stored in your host system.
Make Reversal calls that refence an existing transaction and create a second transaction with negated taxability amounts to "reverse" the original transaction.
Check if a transaction with a specified transactionId exists.

URL for Tax Calculation and Tax GIS API endpoints

The server URL pattern for accessing Tax Calculation and Transaction Management endpoints uses this format:

<server:port>/vertex-ws/<version>/<endpoint>

where:

<server:port> identifies your network address.
vertex-ws designates the Vertex O Series Transaction web service APIs.
<version> is the version of the API.
<endpoint> is the target of the interaction.

For example:

https://example.server.com:8095/vertex-ws/v2/supplies

Tax Calculation API endpoints

Version	Endpoint	Description
`/v2`	`/supplies`	POST - Represents tax calculation from the seller's perspective. Performs a calculation request based on the set property of the Sale Message Type. Valid values are Quotation, Invoice, or Distribute Tax.
`/v2`	`/procurement`	POST - Represents tax calculation from the buyer's perspective. Performs a calculation request based on the set property of the Purchase Message Type. Valid values are PurchaseOrder, InvoiceVerification, Accrual, DistributeTax, or Evaluated Receipts Settlement (ERS).
`/v2`	`/owner`	POST - Represents tax calculation from the owner's perspective. Performs a calculation request based on the set property of the Owner Message Type. Valid values are Inventory Removal and Asset Movement

Transaction Management API endpoints

Version	Endpoint	Description
`/v2`	`/transactions/{id}`	DELETE - Deletes a transaction stored in the host system.
`/v2`	`/transactions/{id}/reversal`	POST - Creates a second transaction with negated taxability amounts to "reverse" the original transaction.
`/v2`	`transaction-exists/{transaction id}`	GET - Checks if the transaction with the specified `transactionId` exists.