SaaS: Software as a Service
Salesforce launched in 1999 with a heretical pitch: software should not need a disc, a server, or a six-month implementation. Oracle and SAP ruled the world with long contracts, on-premise installs, and armies of consultants. Salesforce showed up with a browser-based CRM billed monthly under the banner "No Software," and meant it literally. The economics looked worse at first, because a perpetual license is a big upfront check and a subscription is a small monthly one. But the recurring revenue compounded, and Shopify later showed the endgame: a merchant signs up for one plan, then buys Payments, Capital, Shipping, and Plus until the platform becomes infrastructure nobody wants to rip out.
For founders and operators, the metric that decides everything in SaaS is not new logos, it is whether your existing customers spend more this year than last, even after the ones who left. Cross a certain threshold and your installed base funds your growth on its own; fall below it and you are bailing out a leaky bucket. High gross margins let you pour money into sales and product, but only if the foundation holds. The exact number that flips a SaaS business from leaky bucket to flywheel, and what it has to clear, is what the app holds back.
Frequently asked questions
What is the SaaS model and how does it work?
Software as a Service delivers software over the internet on a recurring subscription rather than as a one-time perpetual license with on-premise installs. Salesforce pioneered it in 1999 with a browser-based CRM billed monthly under the banner "No Software." The upfront economics look worse than a license, but the recurring revenue compounds and high gross margins fund growth.
What are real examples of the SaaS model?
Salesforce launched the model with cloud-based CRM that needed no disc, server, or six-month implementation, challenging Oracle and SAP. Shopify shows the endgame, where a merchant signs up for one plan then buys Payments, Capital, Shipping, and Plus until the platform becomes infrastructure nobody wants to rip out. Both turn small recurring payments into compounding revenue and expanding accounts.
What are the risks of the SaaS model?
The deciding metric is net revenue retention, meaning whether existing customers spend more this year than last even after accounting for the ones who left. Cross a certain threshold and your installed base funds its own growth; fall below it and you are bailing out a leaky bucket. Churn and weak expansion are what break a SaaS business despite healthy new-logo growth.
What can founders learn from the SaaS model?
Founders should focus less on new logos and more on net revenue retention, building products that customers expand into over time so the installed base compounds. High gross margins let you invest aggressively, but only if retention and expansion hold the foundation. CaseBook helps you decide whether this model fits your business, with an AI coach that reads your answer.