Flip-Pay vs Milkie

Flip-Pay has no write-up on Specifiction yet; its figures are above.

Milkie is a paywall SDK for Next.js apps, provided free and licensed under MIT. Developers use its PaywallGate component to protect whole sections or selected components, so a page can contain both free and subscription-only material. A metered setup can grant visitors a limited amount of free access each month. For content that requires sign-in but not a subscription, Milkie describes an AuthGate component. It works with Stripe: users go to Stripe's hosted checkout, and webhooks update subscription status in real time. The maker's README lists support for NextAuth, Clerk, Lucia, Supabase, and other authentication providers, as well as customization of paywall interfaces, messages, and styling. Listed protections include callback URL validation, idempotency keys, PII sanitization, webhook signature verification, and email normalization. Setup calls for three API routes covering subscription status, checkout, and Stripe webhooks. Multi-tenancy, a developer dashboard, a webhook relay, and multiple subscription tiers are roadmap items.