Tiers, allowances, the trial, billing states, and the two authentication backends.
A tier derives from the plan and the subscription status together — either one alone gives the wrong answer. Pro gates a larger daily allowance, more free follow-ups, partner lenses, Research, Insider entry, and the confidence and confluence numbers on the desk. Everything else is free.
The daily analysis allowance is enforced server-side on the UTC day: 2 reads on the free tier and 500 on Pro. A gated read stops before any data is fetched, so nothing is computed and nothing is charged. The signed-out demo counts a different day entirely — the visitor's own calendar date.
Pro is billed through Stripe after a 3-day free trial. The upgrade dialog states the first-charge date and the do-nothing outcome before you click. There is no trial-ending reminder email, because Stripe only sends those for longer trials — so the disclosure happens up front instead.
ORIN runs one sign-in surface over two backends. Hosted gives verified email, real password reset, Google sign-in and cross-device sessions. Device-local keeps credentials on the device and therefore has no password reset — there is no channel over which a link could be sent.