# Web Viewer displays local HTML as plain text (not rendered) when using Post Message or asset URL
**URL:** https://community.thunkable.com/t/web-viewer-displays-local-html-as-plain-text-not-rendered-when-using-post-message-or-asset-url/4107842
**Category:** Issues / Bugs
**Tags:** webviewer
**Created:** [October 29, 2025, 6:57pm UTC](https://community.thunkable.com/t/web-viewer-displays-local-html-as-plain-text-not-rendered-when-using-post-message-or-asset-url/4107842 "2025-10-29T18:57:38Z")
**Posts on this page:** 1
**Page:** 1
### Author:  [@salvadormigarciahw2r](https://community.thunkable.com/u/salvadormigarciahw2r)
#### Post date: [October 29, 2025, 6:57pm UTC](https://community.thunkable.com/t/web-viewer-displays-local-html-as-plain-text-not-rendered-when-using-post-message-or-asset-url/4107842/1 "2025-10-29T18:57:38Z")
Hi everyone,
I’m building an app that uses a local html file to reformat and display an API responses in a styled way. The goal is for the HTML file to act as a render layer with the API text sent into it via the `Web_Viewer → Post Message` block.
Here’s what I’m seeing:
- The html file loads in the Web Viewer (it shows up).
- However, instead of rendering HTML, the Web Viewer **shows the raw HTML source** as plain text.
- Even when I send messages via the `Post Message` block, the content updates, but still as literal HTML text (no rendering).
- The file contains the proper `` structure and the `thunkableWebviewerExtension.js` import for message handling (in case that was needed).
- I’m testing this in both Thunkable Live on iOS and Web Preview, same result.
It seems like the Web Viewer isn’t actually evaluating the local HTML file — it’s just printing it.
**Has anyone successfully:**
- Sent HTML content to a local Web Viewer asset and had it _render_, not print as text?
- Used `Post Message` to inject dynamic HTML into a local file that uses the Thunkable WebViewer extension?
**Expected:** HTML renders normally (e.g., styled text, line breaks)
**Actual:** HTML shows as escaped text (e.g., `content
` instead of formatted output)
Has anyone found a reliable workaround (maybe a `data:text/html` URL or hosted HTML page) to make the Web Viewer actually execute the HTML?