Payments are not the product, but broken billing kills trust on day one. Stripe is the default for UK SaaS MVPs because it handles compliance, cards and subscriptions.
Start with one paid plan, optional trial, Customer portal for self-serve changes and webhooks that update your database. Add usage-based billing only when pricing truly depends on metered events.
Minimum viable billing
- Create Products and Prices in Stripe (monthly first).
- Checkout Session or Payment Link for the first conversion path.
- Store stripe_customer_id and subscription_status on your user or org record.
- Listen for checkout.session.completed and customer.subscription.updated webhooks.
- Gate features in app code from subscription_status, not from guessing.
Trials and upgrades
Trials work when activation is measurable: connect data, invite a teammate, complete one core action. End trial access cleanly with email plus in-app banner.
Use Stripe Customer Portal for plan changes so you do not rebuild billing UI in v1.
Webhook hygiene
- Verify signatures on every request.
- Make handlers idempotent (same event twice should be safe).
- Log failures to a queue you can replay.
- Never trust client-side payment success alone.
Use this as a working checklist inside your team first. When the same steps repeat every week and spreadsheets start breaking, that is usually the moment to scope the smallest reliable integration that removes repeated copy-paste from a core workflow as an owned system. See the relevant Standen service · More guides · SaaS ops audit.