Microform v2 JS SDK RSA Key token generation timeout on external web portal

hdclaims — Wed, 16 Sep 2026 12:07:32 GMT

Hello CyberSource Developer Community,

We are integrating the CyberSource Flex Microform v2 SDK to generate secure single-use payment tokens inside a dynamic web application (hdclaims.co.uk).

Issue Description:

When dispatching the initial capture context request (/flex/v2/tokens) to generate the RSA public key JWT payload, the client-side JavaScript SDK throws an unhandled promise rejection with HTTP 400 Bad Request on initial dynamic form mount. Subsequent retries manually dispatched via Postman using identical merchant credentials return valid JWT keys within 120ms.

Technical Setup:

API Version: CyberSource REST API v2 / Flex Microform v2-0
Target Domain: (hdclaims.co.uk)
Server Environment: Nginx with TLS 1-3 & Cloudflare Reverse Proxy
Browsers Affected: Google Chrome 125, Safari iOS 17

Steps Taken:

Validated merchant ID, Key ID, and Shared Secret signature generation using standard HMAC-SHA256 headers.
Verified CORS headers; Access-Control-Allow-Origin explicitly permits origin handshakes from our web application.
Inspected browser console logs; the iframe container initialized by flex.microform() fails to inject the hosted fields DOM wrapper when single-page routing switches active view states.

Is there a specific execution delay or event listener hook required when re-instantiating the CyberSource Microform SDK on dynamic .co.uk web applications with client-side DOM transitions?

Any technical insights from CyberSource API engineers would be greatly appreciated!

topic Microform v2 JS SDK RSA Key token generation timeout on external web portal in cybersource APIs

Microform v2 JS SDK RSA Key token generation timeout on external web portal