SOFTWARE AS A SERVICE (SAAS)

Software as a Service is the delivery model in which software is hosted centrally and accessed via subscription rather than installed and owned. It became the dominant enterprise software paradigm in the 2010s because it aligned incentives between vendor and customer: the vendor only gets paid as long as the customer finds value, creating pressure toward continuous improvement and customer success.

The unit economics of SaaS are what made investors fall in love with the model. Recurring revenue is predictable and compounds. Customer acquisition costs (CAC) are front-loaded but amortized over multi-year retention. Net revenue retention (NRR) above 100% — when expansion revenue from existing customers exceeds churn — means the business grows even without new customer acquisition.

The key metrics: Annual recurring revenue (ARR), monthly recurring revenue (MRR), churn rate, NRR, CAC payback period, and lifetime value (LTV) to CAC ratio. A healthy SaaS business typically shows NRR above 110%, CAC payback under 18 months, and gross margins above 70%. These benchmarks emerged from a decade of low-interest-rate financing — in the post-2022 rate environment, the emphasis shifted from growth at all costs to efficient growth.

AI's impact on SaaS: AI is both an opportunity and a threat for SaaS businesses. The opportunity: AI features improve product stickiness and justify pricing expansion. The threat: AI agents and copilots may reduce the number of human seats required to accomplish the same workflows, compressing per-seat revenue. The SaaS businesses best positioned for the AI transition are those with deep data moats and workflow integration rather than those selling access to productivity surfaces.

Pricing model evolution: The per-seat subscription model that defined SaaS is under pressure from usage-based pricing — charging for outcomes or consumption rather than licenses. AI accelerates this shift: when an AI agent does the work of ten human users, per-seat pricing breaks down as a value metric. Companies like Snowflake, Twilio, and Stripe built on consumption pricing from the start; legacy per-seat vendors are grappling with whether to migrate their pricing model (cannibalizing near-term revenue) or defend it (risking competitive displacement by usage-based alternatives). The transition to outcome-based pricing also changes the sales motion, the customer success model, and the revenue predictability that made SaaS attractive to investors in the first place.