Fiction with an AI cast that only knows what it should.
Backstory is an iOS studio for writing serialized fiction with an AI cast — where the engine's whole job is keeping track of what every character knows, believes, and conceals.
A character can't use knowledge they don't have. Private facts ship only to the character who holds them — never to the rest of the cast.
Fact, unverified belief, false belief. A character plays their conviction sincerely — and the world never confirms a misunderstanding.
Ask a question you don't want answered yet. The AI decides once, hides the answer even from you, and steers the story toward it. Your own story gets to surprise you.
There are no presets. The Card Studio interviews you, imports your old notes, or hands you a scaffold that keeps characters from going flat.
No account. No servers. No analytics. Your stories live on your device, and the only thing Backstory ever talks to is Anthropic's API — with your own key — to write the next line. Pay once for the app; your words are never our business, literally.