FAQ
Frequently asked questions about ZDR Chat.
Is this really zero server?
Yes. ZDR Chat is a fully static site deployed on Cloudflare Pages. There is no backend server, no database, no API endpoint — nothing that processes or stores data server-side. The only code running is the static HTML, CSS, and JavaScript that powers the PWA in your browser.
Do you see my conversations?
No. Conversations never leave your browser. They’re stored in IndexedDB and transmitted directly from your browser to OpenRouter when you send a message. We (the creators of ZDR Chat) have no access to your conversations, your API key, or any usage data.
What happens if I clear my browser data?
Clearing your browser’s site data for app.zdr.chat will:
- Delete all conversations
- Remove your API key
- Reset your preferences
You’ll need to re-enter your API key and set up your preferences again. This is the same as factory resetting the app.
Can I use it offline?
Partially. The app itself is cached as a PWA, so it loads without internet. However, you need an internet connection to:
- Send messages to OpenRouter
- Fetch the model list
Previously sent messages (cached in IndexedDB) remain viewable offline.
Is the PWA installable?
Yes. ZDR Chat is a fully installable PWA. On desktop (Chrome/Edge), look for the install icon in the address bar. On mobile (Android), you’ll get a prompt to add it to your home screen. iOS users can use the Share menu and select “Add to Home Screen.”
Once installed, it works like a native app — its own window, offline support, and faster startup.
How is this different from ChatGPT or Claude web?
| Feature | ChatGPT / Claude | ZDR Chat |
|---|---|---|
| Server-side storage | Yes (conversations stored on their servers) | No (all local) |
| Account required | Yes | No |
| API key management | Managed by the service | You bring your own |
| Model selection | Limited to their models | 300+ models via OpenRouter |
| Data retention | Logged by default | ZDR by default |
| Cost | Monthly subscription + usage | Pay OpenRouter directly |
| Open source | No | Yes |
What models are supported?
Any model available on OpenRouter — over 300 models including:
- Anthropic: Claude 3.5 Sonnet, Claude 3 Opus, Claude 3 Haiku
- OpenAI: GPT-4o, GPT-4o Mini, GPT-4 Turbo
- Google: Gemini Pro, Gemini Ultra
- Meta: Llama 3, Llama 2
- Mistral: Mistral Large, Mistral Medium
- And many more from other providers
Is it free?
The app itself is free and open source. You only pay for the model usage through OpenRouter. Many free models are available with no cost at all.
What does it cost?
ZDR Chat has no subscription, no platform fees, and no markup. You add credit to your OpenRouter account (as little as $1) and pay per token:
- Free models — $0 cost, rate-limited
- Budget models (GPT-4o Mini, Claude Haiku) — ~$0.15–$1.50 per million tokens
- Mid-range (Claude Sonnet, GPT-4o) — ~$1–$15 per million tokens
- Premium (Claude Opus, GPT-5) — ~$3–$75 per million tokens
Most everyday messages cost less than a penny. The status bar shows your running session cost.
How do I know how much I’m spending?
The status bar tracks tokens in, tokens out, total session cost, and your remaining credit balance. You can see it at a glance while you chat.
Are you making money from this?
No. ZDR Chat is a static site on Cloudflare’s free tier. It costs us ~$0/month to host. We don’t resell tokens, earn commissions, show ads, or collect data. We built this because private AI should be accessible.
Are you affiliated with OpenRouter?
No. ZDR Chat is an independent, open-source frontend. We’re not affiliated with OpenRouter.ai, we don’t earn referral fees, and we have no financial arrangement with them. When you add credit to OpenRouter, every cent goes to OpenRouter.
How do I get support?
Open an issue on the GitHub repository or check the docs for more information.