TECHNOLOGIES

SaaS

Software as a Service

Software you rent instead of own: the vendor hosts it, runs it, and charges a subscription, while customers just log in through a browser.

Last reviewed: 2026-06-02 byKevin Riedl wiki β†—

SaaS is a delivery and business model, not a technology. Instead of selling you a copy of the software to install and run yourself, the vendor hosts it, operates it, and gives you access over the web for a recurring fee. You log in, you use it, you never touch the servers. Salesforce, Slack, and Notion are SaaS. The customer rents capability rather than buying and maintaining software.

The defining technical trait is multi-tenancy: one running system serves many customers at once, with their data isolated from each other. That single choice shapes everything. You design for isolation and security between tenants, for deploying updates to everyone at once without breaking anyone, and for scaling as customers are added rather than shipping a new version once a year. It also changes operations, because the vendor now carries uptime, backups, and security as an ongoing responsibility, not the customer.

The business model is the other half. Revenue is a subscription, usually monthly or annual, which means the relationship does not end at the sale, it starts there. The metrics that matter become recurring revenue, churn, and the cost to serve each customer. Pricing usually ties to value or usage: per seat, per tier, or per volume. Get the pricing model wrong and a technically excellent product still loses money on every customer, so pricing is an architecture decision as much as a sales one.

We build SaaS products end to end, from the multi-tenant architecture to the web app customers log into. Polity is a SaaS product. The honest part founders underprice: the recurring model means you are signing up for permanent responsibility for uptime, security, and support, which is a real operating cost, not a one-time build.

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FAQs

FAQs

Software as a Service: software the vendor hosts and runs, sold as a subscription, accessed over the web. Customers rent the capability and log in through a browser instead of installing and maintaining the software themselves. Salesforce, Slack, and Notion are typical examples.
One running system serving many customers at once, with each customer’s data isolated from the others. It is the defining technical trait of SaaS and it shapes the whole architecture: isolation, security between tenants, and deploying updates to everyone at once without breaking anyone.
Revenue is recurring, usually per seat, tier, or usage, so the relationship starts at the sale rather than ending there. Churn and cost to serve each customer become the numbers that matter. Get the pricing model wrong and even a great product loses money on every customer, so pricing is an architecture decision too.