Integrate void transactions to cancel a previous payment transaction

NOTE: A void cannot be completed after the transfer of funds has been initiated, the timing of which may vary based on scenario. (Please consult your InstaMed Integrations Manager for specific timing rules for your scenario)

Integration Options

Voids may use a different implementation than payment transactions.

Single Sign-On

Review the wizard below for interface display options, code examples and integration details.

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Recommended for new integrations where the user experience is heavily controlled by the software application. 

Explore our REST documentation.  If you need a Sandbox API Key, apply for one here.


HTTP POST Name Value Pair (NVP) is a simple to use format that works across all platforms.

Sample Request

POST /payment/NVP.aspx HTTP/1.1
Host: connect.instamed.com
Content-Type: application/x-www-form-urlencoded
Content-Length: NNN


Sample Response



SOAP Web Services utilizing SOAP version 1.1 or SOAP version 1.2 to transport data. Connectivity requires 2048 bit TLS security.



InstaMed Online

Standalone portal for software vendors who do not yet have a consumer-facing application to embed into.

Using Payment Quick Search, find the payment and click void on the receipt.