Psst has no key of its own inside it. That is a deliberate choice and it changes how the app is priced, how private it is, and what happens when a provider changes their terms.
What a key is
An API key is a password that lets an app call a company's service and bill you for it. Most AI apps hide their own key inside the app and charge you a subscription to cover it. That works until the app has ten thousand users and the provider raises the price.
What Psst does instead
The local engines need no key at all. If you want a cloud engine, you open Settings, paste your own key from ElevenLabs or OpenAI, and press Save. The key goes into your macOS Keychain, the same place Safari keeps your passwords. It is never sent to Kalai Labs. It is never written to a log. The app reads it when it makes a call and nowhere else.
What it costs you
You pay the provider, at their price, only for what you use. Today that is roughly $0.36 an hour for OpenAI Whisper and about $0.40 an hour for ElevenLabs Scribe. Both give new accounts a free allowance. If you dictate ten minutes a day through a cloud engine, the bill is a few cents.
What it costs us
Nothing, which is why Psst can be a one-time purchase. There is no per-user cost hiding behind a monthly fee.
The rewrite
One feature needs a key: select text, hold the hotkey, say "shorter" or "make this a list", and the selection is rewritten. That uses a small OpenAI call. Without a key the button is greyed and everything else works.
Where to get a key
OpenAI: platform.openai.com, API keys. ElevenLabs: elevenlabs.io, Profile, API keys. Copy it once, paste it into Psst, done. If you ever want to revoke it, do it on their site and Psst simply stops using that engine.