What is SaaS Application Development: Guide

SaaS has become the dominant software model in 2025. Research indicates that the average company uses around 112 SaaS applications, while subscription spending has reached an annual average of $3,500 per employee. That makes one thing clear: now is the best time to start SaaS application development.

In this article, you’ll learn how to create a SaaS application from Implex’s CEO Slava Hraichenko, who has 20+ years of engineering experience. We’ll explain the benefits, challenges, and key components of this model. Read on for more!

SaaS is a cloud model in which a vendor hosts, maintains, and continuously updates an application on its own infrastructure. Customers can access this app online through a web browser or via an API. Users typically pay a subscription fee and don’t need to install any software; everything runs on the go.

SaaS app development offers multiple advantages for your product, enabling you to attract a larger customer base due to its convenience. Let’s take a look at the technical benefits.

1. Scalability & flexibility

As SaaS runs on an elastic cloud infrastructure, its capacity can easily adapt to the current load within minutes. Considering that 60% of corporate data is stored in the cloud, most businesses already rely on on-demand scalability to handle traffic spikes and global roll-outs.

The key features for scalability are:

• Auto‑scaling clusters: instantly add CPU, RAM, and storage as usage rises;
• Service‑level scaling: lets you enlarge only the micro‑service under pressure, keeping costs lean;
• Feature flags: turn capabilities on or off per tenant, supporting safe experiments without code forks.

Our web development services can help you get this level of scalability in your product. You’ll be able to use only the required resources, avoiding idle capacity costs. 

2. Cost efficiency for customers

Forrester’s Total Economic Impact studies show SaaS solutions can be 30–50% cheaper than comparable on-premises setups. The benefits gained are primarily due to a significant reduction in capital expenses, allowing businesses to pay a stable subscription fee instead of investing in their own infrastructure.

In short, this includes:

• A subscription-based model instead of buying servers, licenses, and data centers;
• Multi-tenant infrastructure and cloud security costs that don’t fall on the client’s head;
• Automated CI/CD and monitoring tools to minimize development expenses.

Launching the SaaS application development process brings you a significant competitive advantage. You’ll save thousands of businesses from having to invest in their tech, profiting from regular subscriptions. 

3. Faster time-to-market

Teams using Agile and continuous delivery release software about 50% faster than those on traditional cycles, turning ideas into features within weeks. Additionally, SaaS software development enables the integration of third-party APIs and modules, significantly reducing engineering time.

You’ll get a faster time-to-market due to:

• PaaS building blocks like authentication, payments, analytics, and others to slash MVP timelines;
• Continuous deployment that ships code within minutes for fast feedback;
• Global CDNs to achieve global reach without regional roll-outs.

With our application development services, you’ll be ready to launch without delay. Implex’s engineers will help you get a detailed estimate with all timelines, allowing you to plan your release with precision.

4. Easy maintenance & updates

If you decide to create a SaaS application, then you’ll also win by providing a 99% uptime for your users. This type of software is available even during maintenance. However, the best part is that all users receive the updates simultaneously, ensuring everyone gets the same version immediately.

Maximum uptime is possible due to:

• One-click roll-outs to push fixes and features simultaneously for all users;
• Zero-downtime approaches to gradually shift traffic, avoiding regressions;
• Centralized monitoring with unified logs, traces, and alerts.

The result: customers always run the safest and latest version, while engineers focus on new value instead of firefighting. So, if you’re wondering how to develop a SaaS application, consider this feature as well.

5. Accessibility & cross-platform support

SaaS is known for its accessibility, adaptability, and cross-platform support. As mobile now accounts for 61.5% of global web traffic, you’ll get a big win by adapting your solution accordingly. Here’s the best part: you don’t have to install anything to use SaaS software. It just works on the go in your clients’ browsers.

If you’re researching how to build a SaaS application, you’ll have to know the key components of its architecture. We’ll cover the most important aspects below.

1. Multi-Tenant Architecture

A multi‑tenant SaaS runs one codebase for many customers, separating each tenant’s data at the schema, row, or even column level. Because hardware and maintenance are pooled, vendors can offer aggressive pricing. Multi‑tenancy is considered to be “budget‑friendly,” while industry surveys find it trims infrastructure costs by roughly a third compared with single‑tenant deployments.

Some of the benefits of a multi-tenant architecture are:

• Resource pooling: CPU, RAM, and storage expand automatically as new tenants arrive;
• Centralization: one update reaches every customer, simplifying DevSecOps and accelerating feature roll‑outs;
• Fast onboarding: new tenants spin up in minutes without provisioning extra VMs.

2. Single-Tenant Architecture

In a single‑tenant model, each customer receives a dedicated application instance and often a separate database. This ensures full data and performance isolation. However, the extra control comes at a premium: the approach can raise cloud spend by 20–30% because servers, backups, and monitoring are duplicated for every tenant. 

The benefits of a single-tenant architecture include:

• Regulatory compliance: multiple industries need this approach due to HIPAA, PCI DSS, and even FedRAMP requirements to pass audits and get data-residency guarantees;
• Deep customization: in most cases, all elements of the architecture can be fully adapted to your business needs;
• Predictable performance: as you’re the only business using the infrastructure, there won’t be sudden latency issues because of “noisy neighbors.”

3. API Layer and Integrations

Your SaaS solution must have a flexible API layer that allows for seamless integration with other services. A perfect example is Canva’s experience: this tool integrates seamlessly with Google Workspace, Microsoft Teams, Google Drive, and many other solutions.

If you don’t support integrations, then your app doesn’t provide significant value to the user. It should easily become part of your user’s ecosystem, allowing them to automate processes and access data. You can find a list of must-have integrations for each category in the sheet below.

4. Database and Storage

Data is the beating heart of any SaaS, and the cloud oligopoly keeps it pumping: AWS (31%), Azure (24%), and Google Cloud (11%) now hold roughly two‑thirds of global IaaS share. Most vendors will typically focus on these options for their cloud services.

When working on your database and storage, you’ll have to consider these elements:

• Polyglot persistence: sharded PostgreSQL or MySQL for OLTP, NoSQL for high‑velocity metrics, and object stores (S3/GCS) for media to keep workloads right‑sized;
• Geo‑replication & edge caches: used to cut latency for worldwide users and provide zero‑RPO disaster recovery;
• Automated tiering: cold data migrates to cheaper storage classes, reducing bills without sacrificing retention policies.

5. Security and Compliance

Trust is the primary SaaS buying trigger, and the average breach now costs $4.88 million — up 10% year‑over‑year. That’s why you must adopt a zero-trust policy, especially if you’re working with a sensitive niche:

• Encryption everywhere: TLS 1.3 in transit, AES‑256 at rest, and envelope‑encrypted KMS keys protect data across layers;
• Zero‑trust access: short‑lived JWTs, MFA, and fine‑grained RBAC/ABAC to reduce lateral‑movement risk;
• Audit & certifications: SOC 2 Type II, ISO 27001, GDPR, HIPAA, and PCI DSS frameworks with automated evidence collection to shorten sales cycles and raise the compliance bar.

Our SaaS application development guide will help you understand what Implex’s engineers do at each stage of your product’s engineering path. 

1. Research and validation

The SaaS app development process starts by researching your idea and validating it against the market. You’ll get our team’s project managers, business analysts, and developers:

• Analyzing your competitors’ offers;
• Evaluating required features;
• Assessing the product’s viability.

Technical discovery is also included, which involves researching data privacy constraints, compliance triggers, and integration requirements. All these aspects will affect your product’s costs and timelines.

2. Requirements and planning

This is where our SaaS software development guide starts preparing the technical documentation, listing both must-have and nice-to-have features. It also includes user stories, acceptance criteria, and the product’s tech stack. Clear planning provides a perfect forecast to ensure everything works as planned.

3. UI/UX design

Design sprints begin with low-fidelity wireframes and interactive Figma prototypes, allowing stakeholders to click through critical paths before development commences. We apply WCAG 2.2 and EEA accessibility guidelines, atomic design principles, and SaaS UI conventions to minimize cognitive load.

Final deliverables include a component library, responsive layouts, and motion specs. All these are implemented directly into the front-end backlog, shortening implementation cycles and ensuring a cohesive brand experience across web and mobile.

4. Development and integration

Although front-end and back-end development are already launched during the UI/UX design stage, they fully intensify after the visuals are prepared. We build the SaaS app’s architecture and add all required features with future scalability in growth. You’ll also be constantly updated on all changes and receive demos to stay informed. It’s possible to scope adjustments without derailing the overall timeline within the process.

5. Testing and quality assurance

As mentioned previously in our SaaS development overview, quality is an essential part that’s integrated from the very beginning. That’s why we constantly perform throughout the whole process:

• Unit tests;
• Performance tests;
• Load tests;
• Chaos tests;
• Security QA;
• User testing.

This ensures you get a product that’s fully ready for the real world.

6. Monitoring and continuous growth

If we agree to the terms, our engineers conduct 24/7 monitoring of your product to ensure it’s always up and running. You’ll receive new features, performance enhancements, and adaptations to ensure users are always engaged and generate profit.

You already know how to build a SaaS app, but there are still many pitfalls that you’ll encounter in the process. Let’s check out the biggest challenges based on our team’s experience.

1. Scaling and Availability

Your app’s growth may be unpredictable. A viral campaign or even a new enterprise customer can multiply traffic overnight, requiring fast adaptation. Without elastic infrastructure and capacity planning, databases become saturated, latencies spike, and SLAs are compromised. This directly impacts your revenue and reputation.

Implex’s engineers always build your product with resilience in mind. You’ll get horizontal scaling, cross‑region failover, and real‑time health monitoring. It all works while keeping cloud costs sustainable.

2. Regulatory Compliance

All software must comply with a certain set of regulations covering data collection, storage, and breach reporting. Although the specific regulatory bodies may differ, you’ll typically face these three:

• GDPR;
• HIPAA;
• PCI DSS.

Non‑compliance can trigger multi‑million‑dollar fines and block market entry. Because each jurisdiction differs, a global SaaS must juggle encryption standards, data residency controls, retention policies, and ongoing audits. That’s why compliance must be part of your architecture from the very start.

3. Third-Party Integration

Customers judge a SaaS by how well it fits into their existing stack, but every external API introduces dependencies you don’t control. Core workflows are easily broken with:

• Outdated versions;
• Rate-limit changes;
• Sudden outages that don’t depend on you.

The easiest fix is to keep your team constantly monitoring all integrations and adding backward compatibility layers. If your engineers have a straightforward workflow with these situations, they will never have a negative impact on your product’s revenue.

4. Zero-Downtime Deployment

Modern users expect continuous releases yet zero disruption, a paradox when schema migrations, cache warming, and feature toggles touch live traffic. Achieving this balance requires:

• Blue‑green environments;
• Backward‑compatible database changes;
• Automated rollback pipelines.

Even minor issues, such as a missing index or a stale session, can lead to outages, so you must ensure fast and flawless delivery for all users.

What is a SaaS development cost? It’s impossible to provide a one-size-fits-all cost that would apply to all ideas, as multiple factors influence the cost of your SaaS application. These include features, integrations, architecture models, team locations, and dozens of other factors. However, Implex’s team can provide a raw evaluation based on average costs.