Custom Renderers for Svelte with Paolo Ricciuti

In this episode of Svelte Radio, we welcome Jeppe as a new permanent host and sit down with Paolo Ricciuti, Svelte maintainer and Senior Software Developer at Mainmatter, to dive deep into Svelte custom renderers. Paolo walks us through how custom renderers work (using React's approach with React DOM, Ink, and React Native as context), explains the technical challenges of bringing this capability to Svelte 5—including the template element trick, CSP issues, and runtime modifications—and shares his proof-of-concept work enabling Svelte to render to non-DOM targets like terminals and native mobile apps via Lynx.js. The discussion touches on potential use cases like Threlte for 3D graphics, the importance of this feature for Svelte adoption, and wraps up with picks including Screen Studio, TMCP, and Advent of Svelte.



Guest

• Paolo Ricciuti — Svelte maintainer and ambassador, Senior Software Developer at Mainmatter (https://mainmatter.com/svelte)


New Host

• Jeppe joins as a permanent co-host!


Topics Discussed



Custom Renderers Overview

• Svelte Custom Renderers website
• What custom renderers are and why they matter
• How React separates React (the diffing library) from React DOM (the renderer)
• Examples of React custom renderers: 
• Ink (https://github.com/vadimdemedes/ink) — React for terminal/CLI applications
• React Native (https://reactnative.dev/) — React for iOS/Android native apps
• Remotion (https://www.remotion.dev/) — React for programmatic video creation
• React PDF renderer for generating documents


Svelte's Technical Approach

• How Svelte 5 uses the