SaaS development company guide: subscriptions, data and running costs

SaaS stands for software as a service. It is software that customers use online and pay for each month or each year. A SaaS development company plans, builds and launches this kind of product for you.

SaaS has a few parts that a normal website or app does not. It must bill customers again and again. It must keep each customer's data apart from every other customer. And it costs money to run every month. This guide explains each part, so you can judge the companies you talk to.

What does a SaaS development company build?

A SaaS development company builds the whole product and the systems around it:

• The product itself: The screens and features your customers use.
• Accounts and logins: Sign up, log in, team invites and password resets.
• Billing: Plans, trials, payments, receipts and what happens when a card fails.
• Data storage: A database that keeps each customer's data safe and separate.
• Hosting: The servers that keep the product online.
• An admin area: Screens for you to see customers, plans and problems.

What should the first version of a SaaS product include?

Keep the first version small. Build only the parts a paying customer needs at launch:

• One core job: The single task customers will pay for.
• Sign up and log in: With password reset and, ideally, login with Google or Microsoft.
• One or two plans: More plans make billing harder to build and harder to explain.
• Separate customer data: Each company sees only its own data.
• Basic admin: A screen for you to manage customers.

Reports, links to other tools and advanced settings can wait. They are easier to design once real customers tell you what they need. My guide to choosing an MVP development company covers how to cut features with your builder.

How do subscriptions and billing work?

Most SaaS products use a billing service such as Stripe. When a customer subscribes, Stripe creates invoices and tries to collect each payment. It also retries a payment that fails and sends reminders. This is called dunning.

Your product still has to decide what the customer can do at each step. Stripe tracks states such as "trialing," "active," "past due" and "canceled." For example, you must decide what a customer sees when a card fails. You also decide when to lock them out. Your builder should ask you these questions early.

Billing has its own fees. Stripe Billing charges 0.7% of billing volume on its pay-as-you-go plan. Card fees are separate. For US cards online, Stripe's standard fee is 2.9% plus 30 cents for each successful charge.

Sales tax is another point to plan for. Stripe's guide, last updated in November 2025, says 25 US states tax SaaS. It says 7 more tax it if customers must download software. The rules differ by state, so talk to a tax advisor before launch.

How do you keep each customer's data separate?

In SaaS, each customer company is called a tenant. Many tenants share the same system. Keeping their data apart is called tenant isolation.

AWS calls tenant isolation a basic part of SaaS design. It says that if one tenant can reach another tenant's data, the result can be a serious event that a SaaS business may not recover from. In plain words, one data leak between customers can end your business.

There are two common ways to do this:

• Separate databases: Each customer gets its own database. This is very safe but costs more to run and update.
• One shared database with rules: All customers share one database, and rules decide who can see each row of data. This is cheaper and common for new products.

If your builder uses Supabase, these rules are called Row Level Security. Supabase's own docs warn that a table without these rules can be read and changed by any user role that has been given access to it. So ask your builder to show you a test where one customer tries to see another customer's data, and fails.

What does a SaaS product cost to run each month?

Building the product is one cost. Running it is another, and it grows with your customers. Here are the usual items:

Running cost	What makes it go up	Who usually bills you
Hosting	Visitors, page loads and server work	A host such as Vercel
Database	Data stored, users and data sent out	A provider such as Supabase
Payments	Money collected each month	Stripe or a similar service
AI features	How much customers use the AI	The AI company, such as OpenAI or Anthropic
Email	Messages sent	An email service
Monitoring	Errors and logs tracked	A monitoring tool

Watch the free plans. Vercel says its free Hobby plan is for personal, non-commercial use, so a business product needs a paid plan. Supabase pauses free projects after one week without activity. Its paid plan includes set amounts of computing power, database size, data sent out, file storage and monthly active users. A spend cap is on by default. Once you turn it off, Supabase bills extra for use above those amounts.

Ask every builder to estimate your monthly running cost at 10, 100 and 1,000 customers. A good builder can give you a rough answer and explain what drives it.

How do you choose a SaaS development company?

Look for proof that they have built SaaS before. Then test how they think. Ask these questions:

• Can you show me a live SaaS product you built that has paying customers?
• How will you keep each customer's data separate, and how will you test it?
• What happens in the product when a customer's card fails?
• What will the product cost to run each month as it grows?
• Will the code, the hosting, the database and the payment account be in my name?
• Who fixes problems after launch, and how fast?

Also ask what they would cut from your first version. A team that suggests cuts is thinking about your launch date and your budget.

What warning signs should you watch for in a SaaS builder?

• No live SaaS work: They have never shipped a product with billing and many customer companies.
• No answer on data: They cannot explain how they keep customers apart.
• No running cost estimate: They talk about the build price but not the monthly bill.
• Their accounts, your product: They want to keep the hosting or code in their name.
• Every feature at once: They plan a full platform before you have one paying customer.

When should you not build a SaaS product yet?

Wait if you have not yet found customers who will pay. Wait if a tool that already exists does the job well enough. And wait if you can serve your first customers with a simple service and a spreadsheet. A few weeks of selling by hand will tell you more than months of building.

How does Blur Studio approach SaaS development?

I start with the one job your customers will pay for. I build the first version around that job, with billing and separate customer data from the start. Before launch, I test that one customer cannot see another's data. I also give you a plain estimate of monthly running costs, so you can set your prices with care.

The Stripe account, the database, the hosting and the code all sit in your company's name, so you can sell the business or change teams later. After launch, I can take care of updates, fixes and new features. If you plan to add AI features later, my guide to AI integration services explains how that works.