YC Office Hours

A single-file HTML app that acts as a YC-style partner to pressure-test your startup idea. Powered by any OpenAI-compatible chat API, it asks 6 forcing questions to help you validate your wedge, target user, and core problem.

Features

• Single file, zero backend — open index.html and go
• Two modes — Startup (6 forcing questions + design doc) and Builder (hackathon/side project)
• OpenAI-compatible AI config — presets for OpenAI, DeepSeek, GLM/Zhipu AI, SenseNova, OpenRouter, Groq, Together AI, or a custom compatible gateway
• Bilingual — full EN/ZH UI toggle, AI responds in your selected language
• Cloud sync via Supabase — sign in with Google/GitHub to sync sessions across devices
• Offline-first — all data saved to localStorage; cloud is optional and silently degrades
• Design doc generation — auto-summarizes the session into a copyable design document

Quick Start

1. Configure an API

1. Open index.html in a browser (via HTTP server, e.g. npx serve .)
2. Click Settings in the header
3. Choose a provider preset, or select Custom / self-hosted
4. Enter:
   • Base URL — provider root, such as https://api.openai.com/v1 or https://api.deepseek.com
   • Model ID — exact model slug from the provider
   • API Key — stored locally in your browser
5. Click Test connection
6. Close settings, pick a mode, describe your idea

2. Local CORS proxy

Some providers have strict CORS policies. Use the included proxy:

node proxy.js

Then in Settings:

• Keep Base URL set to the upstream provider, not localhost
• Check Use Local CORS Proxy (localhost:3456)

3. Cloud Sync (Optional)

Sign in with Google or GitHub to sync your sessions across devices. Without signing in, everything stays in localStorage — the app works exactly the same.

Supabase Setup

To enable cloud sync for your own deployment:

1. Create a Supabase project at supabase.com
2. Run the schema — paste supabase_schema.sql into the SQL Editor
3. Enable OAuth providers — Dashboard > Authentication > Providers > enable Google and/or GitHub
4. Configure OAuth apps — register your app in Google Cloud Console and/or GitHub Settings > Developer settings > OAuth Apps. Add the Supabase callback URL as a redirect URI.
5. Set credentials — replace SB_URL and SB_KEY in index.html with your project URL and publishable key

API Keys are never synced to the cloud. They stay in localStorage only. Preferences (base URL, model, proxy setting, language) sync on sign-in.

Project Structure

index.html            — Complete app (HTML + CSS + JS)
proxy.js              — Local CORS proxy for OpenAI-compatible APIs
supabase_schema.sql   — Database schema, RLS policies, and GRANTs
supabase_mvp_plan.md  — Original implementation plan

Architecture

Browser
├── localStorage (always, offline fallback)
├── Supabase Auth (Google/GitHub OAuth)
├── Supabase DB (sessions + user_preferences)
└── AI API (OpenAI-compatible chat completions, direct or through local proxy)

Data flow:

• Not signed in → all data in localStorage, zero changes to existing behavior
• Signed in → localStorage + cloud sync; first login auto-uploads existing local data
• Offline → silently falls back to localStorage, cloud writes queue and retry

Security

• API Keys stored only in localStorage, never sent to Supabase
• Supabase publishable key is safe for client-side code; security enforced by RLS
• RLS policies ensure users can only access their own data
• Explicit GRANT statements (required since Supabase April 2026) — no accidental data exposure

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Built to help founders build what people want.