Cloud Tiers & Models

Teachback routes cloud AI sessions through a Cloudflare Worker that proxies to different LLM providers based on your subscription tier.
The X-Tier header is sent with every request so the worker picks the right upstream.

Tier comparison

Tier	Monthly price	Cloud model	Sessions/month	BYOK
Free	$0	Gemini 2.5 Flash Lite	50	Gemini key
Standard	$4.99	Gemini 2.5 Flash	Unlimited	Gemini key
Pro	$9.99	GPT-4o	Unlimited	OpenAI key
Ultimate	$14.99	Claude (Anthropic)	Unlimited	Anthropic key

All tiers have unlimited local sessions (device-only, no cloud AI involved).

How tier routing works

Flutter app
  │  X-Tier: free | standard | pro | ultimate
  ▼
Cloudflare Worker  (tbapi.goappkit.com)
  │
  ├─ free / standard  ──▶  Google Gemini API
  ├─ pro              ──▶  OpenAI API
  └─ ultimate         ──▶  Anthropic API

When a BYOK key is present for your tier, the Flutter app bypasses the worker entirely and calls the provider API directly.

Quota system

Free-tier quota is enforced by a device_quota table in Supabase.
Each device is identified by a UUID stored in secure storage (iOS Keychain / Android EncryptedSharedPreferences).

The worker increments the session count via a Supabase RPC call on each successful completion.
When the count exceeds the tier limit, the worker returns HTTP 429 Too Many Requests.

Upgrading via the app

Open Settings → Current Plan → Upgrade.
Select a tier on the paywall screen.
Complete the in-app purchase via the App Store or Google Play.
Teachback verifies the purchase through RevenueCat and updates currentTierProvider in real time.