SaaS development with billing done properly

A SaaS product is really two products glued together: the feature customers pay for, and the machinery that lets many separate customers pay for it safely. Founders tend to underestimate the second part. Every customer needs a workspace whose data nobody else can see, users need to sign in and invite teammates, plans need limits the app actually enforces, and when a card fails or someone downgrades, the app has to notice. Get those foundations right in version one and every later feature costs less to add.

Multi-tenancy is the part to get right first. For most early SaaS products that means one database where every record carries a workspace ID, with access rules checked on the server for every request, so a customer can never load someone else's data by editing a URL. Separate databases per customer are rarely worth the cost until large customers demand them. Sign-in starts with email, magic links or Google; enterprise single sign-on can wait until a buyer asks for it.

Billing is where quick prototypes usually fall apart. A pricing page with a checkout button is easy; handling trials, proration, failed payments, refunds, taxes and webhook retries is not. We build subscriptions on Stripe, Paddle or Razorpay, keep plan status in sync through webhooks, and give you an admin panel showing every account, its plan and its usage. If you sell worldwide and would rather not handle sales tax yourself, the agent will explain the merchant-of-record option before you choose a provider.

A realistic first version fits in one fixed-price job of up to $4,999: the foundations plus one core feature, done properly. Everything else ships in phases, each quoted on its own once paying users show you what matters. We run our own AI product, GrahAI, used by more than 100,000 people in 9 languages, so we build with the same practical worries in mind: who can see what, what happens at renewal, and how support finds an account fast. You own the code and every account it runs on.