Paste a public GitHub repo URL. Get a narrated explainer video. No accounts.

Live: https://reporeel-marlandoj.zocomputer.io

Built solo in 48 hours for Hackyard Yard #1 — theme: "No accounts."

Give RepoReel any public GitHub repository, pull request, release, or compare URL and it produces a ~60 second narrated explainer video, on the spot:

1. Ingest — pulls the repo's real metadata, README, languages, and commit history from the GitHub API. For PRs: the diff stats and changed files. For releases and compares: the tag, notes, and the commits and files changed since the previous tag.
2. Script — an LLM turns those facts into a 6-scene video script with on-screen copy and a continuous voiceover, grounded in the fetched data. Code scenes are checked verbatim against the fetched source; anything the model invented is flagged.
3. Review (optional, on by default) — the script is shown to the person who started the reel before any rendering happens. Edit any scene by hand, ask the model to rewrite one scene, then approve.
4. Voice — narration is synthesized locally with Kokoro-82M (no cloud TTS).
5. Render — the scenes are compiled into a HyperFrames HTML composition (GSAP timeline, per-scene audio) and rendered headlessly to MP4, with optional burned-in captions and an .srt sidecar.

The finished reel lives at a shareable /v/:id link (with its own poster and OG image) and can be downloaded as a plain MP4. Typical end-to-end time: about 90 seconds.

The style option picks the whole look of the reel: palette, type, motion, camera drift, and the scene composition engine.

bun src/cli.ts https://github.com/owner/repo --style 3b1b
bun src/cli.ts https://github.com/owner/repo --style eli5

The second idea from Karpathy's tips list is that you can explain something in ASD-STE100. RepoReel implements that as two things that share one rule engine in src/lib/ste100.ts:

1. A narration mode. With --plain (or the checkbox in the UI), the script is written under the controlled-language rules of Simplified Technical English and then linted before it is sent to the voice. Any breach becomes a job warning instead of a silent mistake.
2. A standalone operator tool at /ste100. Paste a README, a generated script, or any technical text and get a rule-by-rule report: which rule fired, on which excerpt, and what the fix is. It can also rewrite the text, at three strengths, with or without an AI pass. A static quick-reference is downloadable as PDF or Markdown at /downloads/ste100-quick-reference.pdf.

This is a practical subset of the ASD-STE100 Issue 9 word rules, paraphrased and implemented in software. The check is mechanical: it finds what a program can prove, not what a judge would decide. Full compliance needs the official dictionary, which is a free download at asd-ste100.org. Treat RepoReel as an unofficial aid, never as a certification.

Every reel records the source's pushed_at (and release tag) at ingest time. POST /api/jobs/:id/refresh reports whether the source has moved since, and re-renders on request. Reels pinned to a specific tag or compare range are treated as immutable; releases/latest reels go stale only when a newer release appears.

• No sign-up, no login, no email — not for making videos, not for watching them, not for downloading them.
• No cookies, no tracking, no user identity of any kind. The server keeps a job queue and nothing about you.
• Abuse control without identity: per-IP rate limiting (3 new videos/hour), a bounded queue, and URL-plus-options caching so popular repos render once per format.
• The only per-person state is an owner token, handed back when a reel is started, that gates script editing and cancellation for that one reel. It is never stored server-side beyond the job row.

Every Yard submission is strongly encouraged to include a demo video. RepoReel makes explainer videos for repos — including the other 49 submissions in this Yard. Paste a competitor's repo, get their explainer. You're welcome.

Requirements: Bun, ffmpeg, and Chrome/Chromium (HyperFrames downloads a headless build on first render).

bun install
OPENROUTER_API_KEY=your_key_here bun src/server.ts

Optional environment:

One-off CLI render, no server:

bun src/cli.ts https://github.com/owner/repo
bun src/cli.ts https://github.com/owner/repo/releases/latest --format vertical --grounding both --captions

Hono (Bun) server ── SQLite job queue ── serial worker
                                            │
              GitHub API → StoryFacts JSON  │  src/lib/github.ts
              OpenRouter → 6-scene script   │  src/lib/script.ts
              Kokoro-82M → per-scene WAVs   │  src/lib/tts.ts
              scene JSON → HyperFrames HTML │  src/lib/compose.ts
              headless Chrome → MP4         │  src/lib/render.ts
              review / cancel / refresh     │  src/lib/review.ts, src/lib/queue.ts
              style palettes + layouts      │  src/lib/styles.ts
              ASD-STE100 rules + linter     │  src/lib/ste100.ts, src/lib/steapi.ts
              retention sweep + cleanup     │  src/lib/retention.ts, src/lib/files.ts

Everything is a plain file on disk under data/jobs/<id>/ — the facts, the script, the composition HTML, the final MP4, its poster, and the .srt. Intermediate audio and frame captures are removed once the MP4 exists. Delete the directory and the reel never existed.

Built with Claude (Fable 5) as the coding agent. At runtime, video scripts are generated via OpenRouter (Claude Sonnet 4.5, with Gemini 2.5 Flash and GPT-4o-mini as fallbacks). Voiceover is local Kokoro-82M. All code in this repository was written during the Yard #1 build window (2026-08-28 18:00 → 2026-08-30 18:00 UTC).

MIT