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How to Fix Custom Font Fallback Overrides in Gmail App (iOS & Android)
for Klaviyo Campaigns

A programmatic integration guide for resolving email rendering crashes inside Gmail App (iOS & Android) using Klaviyo's layout editor environment.

Root Bug Analysis

Gmail App (iOS & Android) uses the WebKit / Blink which lacks support for standard rendering rules. This causes Custom Font Fallback Overrides elements to break or collapse when rendering templates.

Active rendering engine: WebKit / Blink

Klaviyo Specific Guide

Klaviyo's delivery wrapper can clean and restructure elements during import, creating dynamic spacing differences inside Gmail App (iOS & Android).

Integration Step:

Open your Klaviyo template editor. Drag an 'HTML' block directly into your layout timeline (do not use a standard text box). Clear the default skeleton content inside the Klaviyo markup editor and paste the RenderOps corrected inline code.

ESP Unsubscribe Alignment

When compiling custom HTML templates for Klaviyo, you must ensure your layout retains deliverability compliance loops. Klaviyo requires you to insert their specific unsubscribe merge tag, otherwise your campaign delivery will be flagged by automated spam audits.

Klaviyo Unsubscribe Tag:{% unsubscribe %}

Documented Client Behavior

Expected layout behavior based on target rendering engine specifications:

Documented behavior: Custom Font Fallback Overrides causes elements to stack vertically or clip in Gmail App (iOS & Android) when templates are sent from Klaviyo.

Interactive Klaviyo Custom Sandbox

Target Environment: Gmail App (iOS & Android)

Auto-compile fixes inside RenderOps Workspace

Load layout code directly into our Font Stack Builder to compile responsive table frameworks that display cleanly in Gmail App (iOS & Android).

Launch Font Stack Builder

Fix Custom Font Fallback Overrides on Other clients for Klaviyo