Cardboard – AI Video Editor in Your Browser

TL;DR

TL;DR: Cardboard is a browser-based AI video editor from YC W26. You describe the edit you want in plain English and it handles cutting, captions, reframing, and composition — no software install needed.

What Is Cardboard?

Cardboard is an agentic AI video editor that runs entirely in your browser. Built by Y Combinator W26 startup usecardboard.com, it lets you go from raw footage to a finished edited video by describing what you want in natural language — no timeline, no keyframes, no learning curve.

According to the founders on the HN launch thread, target customers are marketers, creators, and founders who need polished video content but don’t want to master a traditional NLE like Premiere or DaVinci Resolve.

Core workflow:

1. Upload raw footage
2. Describe the edit in plain English (e.g. “cut to the best 30 seconds, add captions, reframe to 9:16”)
3. Cardboard processes and returns the finished edit

Setup Workflow

No install required — Cardboard runs in the browser.

Step 1: Create an Account

Visit usecardboard.com and sign up. The onboarding was noted as “very pleasing” by early HN commenters.

Step 2: Upload Footage

Drag and drop your raw video files. Cardboard processes everything server-side — your footage never leaves their infrastructure during editing.

Step 3: Describe Your Edit

Type what you want in natural language. Examples from the demo and launch thread:

• “Cut to the best 30 seconds”
• “Add captions to all speakers”
• “Reframe to 9:16 for TikTok/Reels”
• “Remove the background noise”

Step 4: Download or Share

Cardboard outputs the edited video directly. A demo video is available on the product site showing the full workflow.

Practical Evaluation Checklist

Access and onboarding:

• [ ] Browser-only (Chrome, Firefox, Safari)
• [ ] No desktop app or plugin required
• [ ] Sign-up flow completes without errors

Core editing features:

• [ ] Natural language edit descriptions
• [ ] Auto-cutting / best moment selection
• [ ] Auto-caption generation
• [ ] Aspect ratio reframing (9:16, 16:9, 1:1)
• [ ] Basic compositing / transitions

Output:

• [ ] Export formats available
• [ ] Quality suitable for social media / marketing use
• [ ] Processing time reasonable for clip length

Team use cases confirmed on HN:

• [ ] Marketing / promotional content
• [ ] Feature update videos for products
• [ ] Short-form social content

Security Notes

• Video footage is uploaded to Cardboard’s servers for processing — review their data handling policy before uploading proprietary or sensitive content.
• No self-hosted option available as of June 2026.

FAQ

Q: Do I need to install anything? A: No. Cardboard runs entirely in the browser. No desktop app, browser extension, or plugin required.

Q: What video formats does it support? A: Check the official site for the current list of supported input formats. The product targets common formats used by content creators (MP4, MOV, etc.).

Q: Is there a free tier? A: Visit usecardboard.com/pricing for the latest pricing tiers. YC companies often launch with a free trial or freemium tier.

Q: Can I use it for long-form content like YouTube videos? A: The product appears best suited for short-to-medium clips (social media, marketing, promos). Long-form documentary-style editing is likely not the primary use case.

Q: Is the source code open source? A: No public GitHub repository was found for Cardboard as of June 2026. It is a closed-source SaaS product.

Source and Accuracy Notes

⚠️ This section is MANDATORY. All links must be verified from actual source, not guessed.

• Project page: usecardboard.com
• HN launch thread: news.ycombinator.com/item?id=47170174 — YC W26 batch
• License: Closed source (no public repository found)
• Founders: Saksham and Ishan (confirmed from HN thread)

Source last checked: 2026-06-20. Features and pricing are subject to change — verify current offerings at usecardboard.com.