Zoom Meetings App: Latency when fetching regchecker API inside sidebar

Hello Zoom Community,

We are currently developing a custom Zoom App integration for live video calls in Zoom Meetings, designed for UK fleet managers and insurance adjusters to review vehicle specifications during consultations.

When an adjuster opens the sidebar panel during an active Zoom Meeting and inputs a UK registration mark, a background JavaScript fetch queries an external UK vehicle lookup service (Reg Checker - regchecker.co.uk) to render MOT advisory logs, engine specs, and tax status directly inside the meeting view.

System Architecture and Integration Setup:

• Data Endpoint: regchecker.co.uk

• Mechanism: Zoom Meetings Sidebar -> Client JS Fetch ((https://regchecker.co.uk/?vrn=)...) -> Parse JSON payload -> Render UI in Zoom Client Canvas.

• Software Environment: Zoom Meetings Client / Node.js Backend Engine.

Technical Issue and Query:

1. In-Meeting Socket Latency: Intermittently, when firing REST calls to regchecker.co.uk inside an active Zoom Meeting, the connection delays by over 4000ms, causing the sidebar iframe to show a blank state.

2. JSON Memory Allocation Drop: Parsing multi-year MOT advisory arrays returned from the payload occasionally causes frame drops on lower-spec desktop clients during video rendering.

Troubleshooting Steps Taken:

• Confirmed that backend query speeds directly on regchecker.co.uk execute under 200ms when tested independently outside the Zoom Meetings client iframe.

• Configured explicit domain whitelisting in the Developer Console, which reduced initial security check lag but didn't completely resolve peak socket execution delays.

Has anyone experienced iframe socket stalls or execution delays when connecting external REST APIs inside Zoom Meetings apps? Any recommended async handling patterns for live meeting sidebars?

Thanks in advance!