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Mass Payments allows Western Union Business Solutions (WUBS) to provide a payment processing platform to accommodate high volume domestic and FX transactions with API functionality for payment, batching, reconciliation, processing, and sanctions visibility.

The Mass Payments platform supports a fully automated transaction lifecycle via an Application Programming Interface (API) based channel for a batch integration model.

Mass Payments allows customers to submit batches of beneficiary payments to WUBS  for processing and to specify how they will fund each payment within a batch.

With this model, the customer is able to plan and budget for the remittance of a specific batch of payments.

A single batch can consist of payments with different trade (payout) and settlement currency combinations including:

  • Different trade currencies for the same settlement currency.

  • Different settlement currencies for the same trade currency.

  • Trade currency same as settlement currency.

NOTE: Payments with the same trade/settlement currency combination can only be assigned one currency (trade or settlement) as the fixed amount.

General Information on the API

WUBS is using a REST based API with JSON structured payload for the Mass Payments product. 

WUBS Mass Payments' URL prefix is

API Security

The API Suite offers two methods for authentication:  OAuth2.0 and PKCS12 client certificate. To use either method, you will need to contact WUBS to provision a sandbox and / or production account. WUBS does not support self-service partner or customer sign-up at this time. 

OAuth2.0 authentication

The preferred method of authentication to the API is OAuth2.0. Using this method, the partner will be assigned credentials that will be used to retrieve an API token. This token will need to be passed along with each API request. A new token will need to be acquired every 30 minutes.

PKSC12 Client Certificate
The alternate method of authentication is the PKSC12 client certificate. In this method, all API calls should include a valid certificate associated with the partner ID. Any calls without a client certificate will be rejected.

Before a certificate expiration, a new client certificate will be issued to a Partner for an uninterrupted access.


For a resource identifiable by external to WUBS ID (Partner Assigned ID) a PUT method will be used to push a resource to WUBS. Examples of those resources are: payment, customer, beneficiary.

  • Acceptable external ID is an alphanumeric string (with hyphens or underscores - [a-zA-Z0-9-_] ) up to 38 chars long - all GUID like IDs will be accepted.

For a resource identifiable by WUBS generated ID (WUBS assigned ID) a POST method will be used to request a resource creation to WUBS. Examples of those resources are: quote, order.

If a request allows to submit request for multiple resources, a limit will be imposed for the total count of input resources.

If a result assumes a collection of resources, a limit will be imposed for the total count of output resources.

To allow equal and uninterrupted access to WUBS resources for all API consumers a limit could be imposed on a total number of API calls originated by a Partner. That limit will be reset on a daily basis.

  • All dates and timestamp type values provided by WUBS should be using ISO 8601 and be in UTC, unless specifically indicated. Example: "2015-08-30 13:15:30Z'.

  • All currency codes are defined as in ISO 4217 (http://www.currency-iso.org/dam/downloads/lists/list_one.xml), Example - USD, EUR, JPY.

  • All country codes are defined as in ISO 3166 two-letter code (alpha-2) (https://www.iso.org/iso-3166-country-codes.html). Example - US, NP, AU.

  • All amounts should be defined and submitted as integer and assumed to be in cents (minor currency unit) value. Number of cents are defined in the same ISO 4217. Example - 10089 would represent 100.89 USD or 10089 JPY or 10.089 KWD as a minor currency unit defined for USD is 2, for JPY, CLP, and XPF is 0 and for KWD is 3.

  • Default timeout for HTTP request is set to 100 sec.

  • The following characters are reserved in JSON and must be properly escaped to be used in strings:

  • Double quote (“) is replaced with \"

    • Backslash (\) is replaced with a \\

    • Backspace is replaced with \b

    • Form feed is replaced with \f

    • Newline is replaced with \n

    • Carriage return is replaced with \r

    • Tab is replaced with \t

  • SWIFT accepted characters only

New Currency Capabilities Sheet available September 2021

Find it at: Currency Capabilities US September 2021

Versioning: Mass Payments Project


Mass Payments


Mass Payments Team & Tech Comms


Draft payments, settlement tables


V4.6 February 2022

Western Union Business Solutions

© 2020 Western Union Holdings, Inc. All Rights Reserved. Western Union Business Solutions (“WUBS”) is a business unit of The Western Union Company and operates through local affiliates in a number of countries around the world. For a full list of WUBS local licensing and other information, please click here. This User Guide has been prepared solely for informational purposes and does not in any way create any binding obligations on either party. Relations between you and WUBS shall be governed by the applicable terms and conditions. No representations, warranties or conditions of any kind, express or implied, are made in this User Guide.

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