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Plans & Usage

FastSvelte meters usage and enforces per-feature limits through one generic system. The same engine powers the note quota and the AI token allotment — and you can extend it to anything.

How it works

  • Plans define limits. Each plan carries a features map (typed by PlanFeatures + the FeatureKey enum in backend/app/model/plan_model.py). The kit ships max_notes, token_limit, and enable_ai.
  • Usage is metered per billing period. OrganizationUsageService tracks each org's consumption per FeatureKey against the plan's limit, scoped to the current subscription period — it resets when the period rolls over.
  • Limits are enforced. Call check_quota_for(...) before an action and update_usage(...) after:
if not await usage_service.check_quota_for(org_id, FeatureKey.MAX_NOTES, 1):
    raise QuotaExceeded(FeatureKey.MAX_NOTES)
# ... perform the action ...
await usage_service.update_usage(org_id, FeatureKey.MAX_NOTES, 1)

The note demo does exactly this on create and delete.

Configuring limits

Set each plan's limits in its features map via the admin Plans page or seed data — see Admin & User Dashboards. How plans map to Stripe products is covered in Billing & Subscriptions.

Add your own metered feature

Metering a new feature is a small change: add a FeatureKey + PlanFeatures field, set limits per plan, and wrap your action with check_quota_for / update_usage. Full walkthrough: Metering a Custom Feature.

AI usage

The AI token allotment (token_limit) is just one metered feature — but it adds a paid credit top-up layer on top. See AI Usage & Credit Billing.