Models & BYOK

Synthetic BrAIn is model-agnostic. The language model is an engine you can swap — you are never tied to a single vendor.

Your options

• Local models — run a model on your own hardware. Nothing leaves your machine. Best for maximum privacy and offline use; capability depends on your model and hardware.
• Bring your own key (BYOK) — connect a frontier provider (for example OpenAI or Anthropic) using your own API key or account. You get frontier capability, billed by that provider to you, under their terms.

Connecting a provider

1. Open Settings → Providers → Accounts to sign in to a provider (for example OpenAI via OAuth), or Providers → API keys to paste your own key.
2. Your key is stored in your device's secure store, for the app's use only. We never receive it.

Choosing the active model

1. Open Settings → Model.
2. Pick the provider, then the model, and press Apply. This applies to new sessions.
3. To hot-swap the model in a chat you're already in, use the model picker in the composer.

You can connect more than one provider and switch between them at any time.

What happens to your prompts

• With a local model, your prompts stay entirely on your device.
• With a BYOK provider, the prompt you send is transmitted to that provider using your key, and is governed by that provider's terms and privacy policy — not ours. We are not in the middle of that exchange and do not receive its content.

Costs

BYOK usage is billed to you by the provider whose key you use. Some optional features (for example an external coding agent) rely on a third-party service billed separately by that provider. These costs are yours and are independent of your Synthetic BrAIn licence. See Licensing, trial & the bundle.

Switching models later

Because your memory and context live in the Brain — not in the model — you can change providers without losing your history. That's the point: change the model, keep your mind.