SaaS applications: definition, architecture, stages and costs

SaaS application development is a rapidly growing market. SaaS applications support businesses daily in their various needs and address a major challenge: mobility. Before diving into developing these applications, it’s important to understand what SaaS is and its benefits. This guide explains the SaaS model, its architecture, the stages from MVP to scale, and the main cost drivers.

What is SaaS application development?

SaaS stands for “Software as a Service,” which translates to “logiciel en tant que service” in French. A SaaS application is an online-hosted application that doesn’t require installation on a computer or other device. It’s accessible from anywhere, simply via an internet connection and a browser.

For several years now, the SaaS application model has far surpassed the traditional model of software installed on a computer. 

What are the advantages of SaaS application development?

SaaS application development owes its success to the many advantages it offers, both for businesses and their customers.

The advantages of SaaS applications for businesses

Users can start using the application quickly.Since no download or installation is required to use the application, users can start using it very quickly. This makes onboarding much easier and faster than if they had to download and install software. This significantly increases the number of users.

Billing is simple and automatic. SaaS applications typically operate on a subscription basis. Billing is generated automatically based on each subscription, and payments are processed online, just like any other internet purchase.

“Simple and automatic” needs qualifying, because recurring billing concentrates a good share of production incidents. Three rules avoid the most expensive ones. Subscription state must be driven by the payment provider’s webhooks, signature verified against the raw body, an immediate 2xx response, processing in the background, and not by the browser’s return, which is lost if the user closes the tab. Events must be deduplicated on their id, since the same one can arrive twice and arrival order is not guaranteed. And payment failure needs a designed path: retry, grace period, then restricted access. An application that cuts access on the first declined charge loses solvent customers.

Reduced development costs. A SaaS application consists of a single core block to which features are added as optional modules based on the client’s needs. Unlike installed software, there’s no need to create multiple distinct versions. This helps save on application development costs.

That shared “single block” carries a SaaS application’s central risk, and it deserves naming: isolation between customers. When every account lives in the same database, each query must filter on the organisation, without exception, one omission on a single screen or a single API endpoint exposes one customer’s data to another. This is broken access control, the first category of the OWASP Top 10, and it is the most serious incident a software vendor can face. Two practices prevent it: apply the filter at the database level or in a single layer every access passes through, and test systematically with two accounts from two different organisations.

The advantages of SaaS applications for customers

An up-to-date application. The customer no longer needs to worry about updating their application. Since SaaS applications are hosted online, the application is always kept up to date by the developers. All users benefit from the same version of the application at the same time, without having to download or install updates.

An always-up-to-date application also implies an ongoing responsibility for your customers’ data, and two points come up systematically in procurement questionnaires. Reversibility: a customer must be able to retrieve their data in a usable format, and that is a feature to build, not a sales promise. Retention: the French regulator’s developer GDPR guide is a reminder to define durations and document what happens on termination, deletion, anonymisation or restricted-access archiving. Answering those two questions before your first enterprise customer saves weeks on the first tender.

Resource usage. SaaS applications do not use the customer’s hardware resources. Since the application is fully hosted online, the hosting provider supplies the power needed to run it. This makes the required hardware resources much more accessible for the customer.

A price tailored to specific needs. Thanks to the subscription-based payment model with selectable features, the client can tailor the offer precisely to their needs. More specifically, they can adjust their plan based on the number of users required and the features needed. This allows the client to save money since there’s no upfront investment to amortize.

The flexibility of the offer.SaaS applications offer clients a certain degree of flexibility. Depending on the plan, clients can add or remove users or features from their subscription at any time.

Mobility. SaaS application development is a major asset for mobility. Applications are accessible from anywhere, at any time. Whether the client is in the office, traveling, working remotely, or at a trade show, the app remains accessible from any device.

Examples of SaaS applications

Here are a few examples of SaaS applications you’ve likely used in a business setting or are already familiar with:

Webflow

Webflow is a SaaS-developed application that allows you to create a website without writing a single line of code. Webflow offers affordable plans, enabling startups with limited budgets to easily and quickly build a website. You can create anything from a showcase site to an e-commerce platform, with a wide range of templates to get started.

Like many no-code tools, Webflow relies on a drag-and-drop principle via a highly visual graphical interface.

At Scroll, we specialize in no-code, and Webflow is one of our primary tools. We use it daily to create and enhance our clients’ websites. That’s why we’ve even developed a unique offering to design websites faster and more flexibly for our clients: the Webflow agency.

Salesforce

The Salesforce CRM is a well-known and widely used SaaS application in businesses. It’s a fully cloud-hosted app that helps companies collaborate with their customers, offering powerful customer management solutions.

Slack

Slack is a real-time messaging SaaS application. Increasingly popular in businesses, Slack enables team communication via channels, video conferencing, and instant messaging, a highly effective tool for team collaboration on any project.

Canva

Canva is a SaaS application dedicated to graphic design. It allows users to easily create presentations, logos, and other graphical elements, with access to templates, icons, and images to support the creative process.

entrust your SaaS development to a product team

Have Scroll develop your SaaS

Understanding the stack and steps is useful. But turning that into a reliable SaaS in production, architecture, security, scalability, deadlines met, requires a team experienced in AI-assisted coding.

Scroll develops your custom SaaS application using AI-assisted code, from MVP to scale, or takes over an existing prototype (free 48-hour diagnosis).

Scroll agency supports you in developing your SaaS application

Want to create a SaaS application for your business? At Scroll, we specialize in no-code web app development. Whether you're launching a new SaaS project or revamping an existing one, our team will work with you to deliver tailored solutions. For TPEs and SMEs alike, reach out to discuss your project and learn more!