Presentations Without PowerPoint or Cloud: Open-Source Bento Editor Packs Slides and Engine Into a Single HTML File

Bento, a free open-source presentation editor, is gaining traction among developers as an unconventional alternative to PowerPoint and Google Slides. Its main selling point is extreme self-containment: the document, multimedia assets, animation library, and editing interface are all packed into a single HTML file weighing about 600 KB.

Full Offline, Morph Animations, and Encryption

A .bento.html file runs in any modern browser without installing utilities, extensions, or logging in. As the creators explain in the project’s GitHub repository, all slide content is stored directly in the page’s code as structured JSON. When you save changes, the file rewrites itself, so you can send a finished presentation via messenger or carry it on a USB stick: no connection to the developers’ servers is needed for editing or presenting.

Despite its lightweight nature, the tool offers a full-fledged set of visual features:

• Support for vector shapes, tables, charts, audio, and embedded video;
• Advanced dynamics, including moving elements along curved paths, cinematic zoom on photos, and smooth Morph transitions between slides;
• Presenter mode with hidden slide notes, a timer, and PDF export.

For collaborative work, there’s a session-based multiplayer mode with co-author cursors. Synchronization is protected by AES-GCM end-to-end encryption: the relay server only receives encrypted packets and has no access to slide content.

How PowerPoint Import Actually Works

The claim circulating online that the program “instantly restores old PowerPoint presentations” needs clarification: there’s no native button for directly importing .pptx files in the interface.

Instead, the authors propose a different approach, detailed in the Bento user guide. Users are advised to upload the original presentation into a chat window with an AI assistant—ChatGPT, Claude Code, Cursor, or Gemini—attaching the project’s open system prompt. The language model parses the slide structure and generates clean JSON code for Bento’s markup.

Thanks to Bento’s simple markup, it has become a handy tool for AI agents: models with file system access can create or modify slides directly in the page’s source code.

The core Bento Slides module is distributed free under the MIT license on the project’s official website. The team plans to expand the concept: in the future, they intend to release similar self-contained HTML containers for spreadsheets and notes.