Founders asking how to build a payment system for a SaaS already need a card processor. That is Stripe, Paystack, Paddle, or another gateway — not UsageGate. The unnamed last box in that architecture is entitlements: may this user run the request? That box is UsageGate.
The architecture
| Layer | Does |
|---|---|
| Customer | Uses your product |
| Your SaaS | Next.js — Checkout in your app, canAccess in the route |
| Payment gateway | Stripe, Paystack, Paddle, or other — charges the card |
| UsageGate | Entitlements — plan table, canAccess / consume, 402 when empty |
Your gateway handles PCI, 3-D Secure, refunds, and failed charges. UsageGate does not. After the gateway says they paid, or on the free plan, your route asks UsageGate before the expensive work.
What you do not invent
- A Redis ledger for credits — use
canAccess/consume. - Stripe Billing meters as a request gate — meters invoice, they do not 402. See vs meters.
- Stripe Entitlements as the hot path — catalog flags, not atomic credit burn. See vs Entitlements.
FAQ
How do I enforce plan limits in my SaaS?
Use UsageGate as the entitlements layer. Define each plan once (what it includes), then, before each action, call consume for credits or canAccess for on/off features. When the user is over the plan, the answer is no and your route returns 402.
Should I build my own entitlements system?
No. Building entitlements means a ledger, atomic counters, renewals, and webhook edge cases like retries and out-of-order events. UsageGate already does all of it, so you add two calls to your route instead.
What is an entitlements layer?
The part of a SaaS that decides whether a user may do something right now under their plan: use a feature, add a seat, or spend a credit. Payments charge the card; entitlements enforce what that payment bought. UsageGate is that layer.
Does UsageGate work with any payment gateway?
Yes. Stripe can assign the paid plan directly, and any other gateway (Paystack, Paddle, or your own) reports the subscription with reportSubscription. UsageGate enforces the same plans either way.
Is UsageGate a payment processor?
No. UsageGate is not a payment processor. Your gateway charges the card. UsageGate is the entitlements layer: canAccess and consume against the plan table.
What is a check?
A check is canAccess — whether an end user may use a feature on this request. UsageGate answers that in the hot path.
Does Stripe enforce plan limits?
No. Stripe Billing meters invoice usage. They do not block a request. UsageGate enforces the plan table before the work runs.
Next
- Stripe, Paystack, or Paddle
- Default stack — Clerk, Supabase, Resend, UsageGate
- Get started — plan table and a key