Unexpected PDF Output from IronPdfEngine Docker

Updated:June 28, 2026

A PDF rendered through IronPdfEngine Docker can come out missing styles and fonts, even though the same HTML renders correctly when run locally. This usually shows up when the HTML references external stylesheet or font files.

IronPdfEngine Docker runs in an isolated environment and cannot reach external resources on your machine. Any stylesheet or font file the HTML points to outside the container is unavailable at render time, so those styles and fonts never make it into the output.

Solution

Make every resource the HTML needs available to the container. Either inline them or ship them alongside the HTML.

Option 1: Embed Styles and Fonts

Place the styles and fonts directly inside the HTML string so the markup carries everything it needs. With nothing to fetch externally, the container renders the page exactly as written.

Option 2: Send a Zipped Folder

Put the HTML file together with its style and font files into a single zipped folder, then pass that folder to IronPdfEngine Docker with RenderZipFileAsPdf(). The engine unpacks the archive and resolves the local references against its own contents.

Either approach gives the container local access to the styles and fonts, so the generated PDF matches what you see when rendering locally.

Curtis Chau

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Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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