Use your own provider key so usage is billed to your account at your rate.
Add your own Anthropic or OpenAI key and Convaa spends that instead of ours. Usage lands on your provider bill at whatever rate you have negotiated, and it unlocks the premium models on that provider.
Keys are encrypted at rest and never returned to the browser — the app can tell you a key is present and show its last four characters, and that is all.