Build your own Loom.

# Build an original app inspired by Loom

You are an experienced product designer and full-stack engineer. Build a working, polished MVP from the brief below. Implement the core journeys end to end; a static mockup is not sufficient. Inspect the current environment, make sensible implementation decisions, and get started. Ask a question only if a missing answer genuinely blocks implementation.

Starting platform: Web. Explicit customized Product & audience and Tech stack requirements take precedence over this starting target.

## Product & audience
Build an original asynchronous screen recording app called Showtell, inspired by Loom. It is for people explaining work with short videos. The primary flow is choosing a screen, recording with optional microphone audio, saving the recording, and watching or sharing it.

## Design
Use a simple recorder with a prominent start/stop control, explicit device permissions, a recording timer, and clear privacy status. The library has readable video cards. Playback pages use a large player with a transcript-free notes and timestamped comments panel.

## Features
1. Recording: use browser screen capture and MediaRecorder APIs with explicit user permission; allow microphone audio when supported; show timer, stop, and cancellation controls.

2. Device handling: explain denied permissions and unsupported browsers; clean up every media track on stop, cancel, or navigation. Warn about browser and system-audio limitations.

3. Library: name recordings, add descriptions, organize into folders, and delete with confirmation. Generate thumbnails from the recorded video.

4. Playback: seek, change playback speed, download recordings, and add notes linked to playback timestamps. Clicking a note seeks the player.

5. Sharing: if a real upload backend is configured, upload videos with progress and produce scoped share links; otherwise provide local playback and file download with clearly labeled local-only storage.

## Tech stack
Use the existing repository and conventions if there is one. If starting from scratch, use React with TypeScript and a practical, lightweight styling approach. Pick well-maintained libraries only when they materially help. Keep components, domain logic, and data access separate. Explain your chosen stack briefly, then begin implementation.

Follow the persistence requirements in Data & behavior. Personal tools may use IndexedDB. Products with public submission, bookings, permissions, or shared messaging require an authenticated backend with server-side authorization and durable storage. Use infrastructure already available in the environment. Do not put secrets in frontend code. If external infrastructure is unavailable, build a clearly labeled local demo, provide the schema and setup instructions, and state which shared features need configuration. Do not present simulated sharing or authentication as production functionality.

## Data & behavior
Recording {id, ownerId, title, description, duration, mimeType, size, createdAt, folderId, storageKey}; Folder; TimestampNote {id, recordingId, seconds, text}; optional Share {id, recordingId, tokenHash, expiresAt}. Use IndexedDB for local blobs, check storage quota, and use object storage plus authenticated metadata for online sharing. Never claim a blob URL is a public share link.

Acceptance checks and scope:
Test denied permissions, screen-share termination, microphone absence, recording cleanup, save quota errors, reload playback, and timestamp seeking. Reject unsupported file types and report upload errors. Exclude cloud transcoding, automatic transcripts, AI summaries, and browser extensions from the MVP.

## Originality and assets
The named product is a reference for general workflows only. Use an original product name, visual identity, wording, layout, and assets. Do not copy proprietary code, branded logos, distinctive screens, private APIs, paid templates, or protected media. Use original or appropriately licensed sample data and assets. Build from this brief rather than scraping the reference service. Do not imply affiliation with the referenced company.

## Implementation quality
- Make every visible control work, with clear loading, success, empty, validation, and failure states. Remove controls for unimplemented features.
- Support the target platform and responsive or resizable layouts where appropriate. Use platform-appropriate accessibility semantics, labels, keyboard operation, visible focus, sufficient contrast, and reduced-motion preferences. Provide alternatives for drag-only interactions.
- Validate inputs at the relevant boundary. Treat imported or user-generated content as untrusted; render it safely. Confirm destructive actions or offer undo.
- Keep state changes reliable across navigation and reloads. Never silently lose edits. Handle persistence and network errors with an actionable message.
- Keep the scope realistic. Prioritize the complete primary journey. If a custom Features section differs from the baseline, update the data model, design, and acceptance checks to match it; explicit custom requirements take precedence over baseline assumptions.
- Provide realistic original sample content and a useful empty state. Keep sample data clearly separate from user-created data.

## Delivery and verification
1. Inspect the repository and outline the implementation in a few sentences.
2. Implement the app and connect its actual data flow. Continue until the primary journey works.
3. Run appropriate checks and test the acceptance cases above on the target platform. Verify responsive layouts and keyboard navigation when browser tools are available. For native projects, build with the available SDK and test an emulator or device when possible; report any missing native verification honestly. For games, verify the rules and gameplay loop, not only the menus.
4. Fix observed failures, then provide the runnable result, setup/run instructions, a brief explanation of what is implemented, and any specific configuration or verification limits.

This is a focused MVP. Do not add billing, AI services, or unrelated features unless explicitly requested in the brief. Start building now.