SaaS (Software as a Service) is a software distribution model in which applications are hosted in the cloud and delivered to users over the internet via a subscription. Users access SaaS products through a web browser — no installation, no hardware requirements, no IT infrastructure to manage.
Familiar SaaS examples include Salesforce, Slack, HubSpot, Notion, Zoom, and Google Workspace. The model has largely replaced packaged software in enterprise and SMB markets.
How SaaS Works
In a SaaS architecture:
- The software provider hosts the application on cloud infrastructure (AWS, GCP, Azure)
- Customers pay a recurring subscription fee (monthly or annual)
- Users log in via browser or mobile app
- The provider manages all updates, security patches, and infrastructure scaling
- Customer data is isolated within the multi-tenant environment
Customers get always-current software with zero maintenance burden. Providers build a recurring revenue business with compounding growth.
SaaS vs. Self-Hosted Software
| SaaS | Self-Hosted | |
|---|---|---|
| Installation | None — browser access | Installed on customer servers |
| Maintenance | Provider manages | Customer manages |
| Updates | Automatic | Manual |
| Data control | Provider's servers | Customer's servers |
| Cost model | Subscription (OpEx) | License + infrastructure (CapEx) |
| Customization | Limited to provider features | Unlimited |
For industries with strict data residency or compliance requirements (healthcare, government, finance), self-hosted software may be mandatory. For most businesses, SaaS reduces total cost of ownership.
Multi-Tenancy: The Architecture of SaaS
Multi-tenancy is the technical model that makes SaaS economically viable. A single application instance — one codebase, one infrastructure — serves thousands of customers simultaneously. Each customer's data is isolated, but the underlying infrastructure is shared.
Benefits of multi-tenancy:
- Lower infrastructure cost per customer
- Shared updates and security patches
- Easier to maintain and scale
- New features deploy to all customers simultaneously
Implementation models:
- Shared database, shared schema — most efficient, requires careful data isolation
- Shared database, separate schema — moderate isolation, more storage overhead
- Separate database per tenant — highest isolation, highest cost, used for enterprise tiers
SaaS Business Metrics
Understanding SaaS health requires tracking specific metrics:
| Metric | Definition |
|---|---|
| MRR | Monthly Recurring Revenue — total subscription revenue per month |
| ARR | Annual Recurring Revenue — MRR × 12 |
| Churn Rate | Percentage of subscribers who cancel per period |
| LTV | Lifetime Value — average revenue per customer over their subscription lifetime |
| CAC | Customer Acquisition Cost — cost to acquire one paying customer |
| LTV:CAC Ratio | Sustainable SaaS businesses target 3:1 or higher |
A SaaS business is healthy when LTV significantly exceeds CAC and churn is low enough for compounding MRR growth.
Core Components of a SaaS Product
Building a SaaS product requires careful architectural decisions beyond typical website development:
- Authentication and authorization — user accounts, roles, permissions, SSO/SAML for enterprise
- Subscription billing — recurring billing, trial management, plan upgrades/downgrades (Stripe Billing)
- Multi-tenant data isolation — ensuring customer data cannot be accessed by other tenants
- Usage metering — tracking feature usage for usage-based billing models
- Admin dashboard — internal tools for support and customer management
- Webhook and API layer — integrations with third-party tools customers expect
- Audit logging — required for SOC 2, HIPAA, and enterprise compliance
How Moydus Helps
Moydus builds custom SaaS products and web applications from the ground up — handling architecture design, multi-tenancy implementation, subscription billing integration, and scalable web development. Whether you are validating an MVP or scaling an existing platform, we provide the technical foundation for sustainable SaaS growth.
Contact us to discuss your SaaS project.