SaaS fundamentals
What Is Software as a Service (SaaS)? A Plain Definition
In short
Software as a Service (SaaS) is software hosted and maintained by a vendor and accessed over the internet, usually paid for by recurring subscription per user or per usage. The customer never installs or updates the software and does not own a copy of it.
The definition
Software as a Service (SaaS) is software that a vendor hosts, operates and updates, delivered to customers over the internet and paid for by recurring subscription. You log in rather than install. The vendor owns the servers, the deployments and the uptime. You own your data and your configuration, and you stop having access when you stop paying.
That last clause is the whole difference from the software model that came before it.
What changed, concretely
| Traditional licensed software | SaaS | |
|---|---|---|
| Payment | One-off licence, optional support | Recurring subscription |
| Installation | On your machines or servers | None — accessed in a browser |
| Updates | You choose when, or never | Vendor decides, usually continuous |
| Infrastructure cost | Yours | Vendor’s, included in the fee |
| If you stop paying | Software keeps working | Access ends |
| Data location | Your premises | Vendor’s cloud |
| Customisation | Deep, sometimes unlimited | Bounded by what the vendor exposes |
Why vendors prefer it
Predictable recurring revenue is easier to forecast, finance and value than lumpy licence sales. It also means one codebase in one environment rather than supporting nine versions across customer hardware, which drastically lowers the cost of shipping changes. Those two facts explain nearly all of the industry’s shift, and neither of them is about customer benefit.
Why customers accepted it
Three real advantages, none of them small:
- No upfront capital. A team can start using a $20/month tool this afternoon without procurement.
- No maintenance burden. No servers, no patching, no upgrade projects.
- Access from anywhere. Which turned out to matter more than anyone predicted in 2019.
The four costs that appear later
- Price rises at renewal. Subscriptions are repriced; licences are not.
- Per-seat drift. Costs grow with headcount whether or not usage grows with it.
- Sprawl. Mid-sized companies routinely discover they are paying for dozens of overlapping tools nobody owns.
- Switching cost. Your data exports; your workflows, integrations and institutional habits do not.
Where SaaS is the wrong model
It is not universal, and the exceptions are consistent:
- Strict data residency or air-gapped environments. Some regulated and defence contexts cannot send data to a third party at all.
- Very long-lived, unchanging tools. If the software will not need to change for a decade, you are renting something you could have bought.
- Extreme customisation. When you need to modify behaviour the vendor has not exposed, you need code you control.
- Predictable heavy compute. Above a certain scale, running it yourself is cheaper — which is why some companies move off managed platforms as they grow.
The questions worth asking before you subscribe
Not the feature list. These:
- What does this cost at three times our current size?
- Does the price count users, records, contacts or usage — and which of those grows fastest for us?
- Can we export everything, including configuration, in a format another tool can read?
- What is the notice period, and does the contract auto-renew?
- Who at our company owns this subscription, and what happens when they leave?
If you want the longer version of that list, see our guide to when a free trial is the right way to evaluate SaaS.
Frequently asked questions
What does SaaS stand for?
SaaS stands for Software as a Service. It describes software that a vendor hosts and operates, which customers access over the internet — normally through a browser — in exchange for a recurring fee rather than a one-off licence purchase.
What is the difference between SaaS, PaaS and IaaS?
SaaS delivers a finished application (Gmail, Notion, HubSpot). PaaS delivers a platform for running your own application without managing servers (Heroku, Vercel). IaaS delivers raw computing infrastructure you configure yourself (AWS EC2, Google Compute Engine). The further down the list you go, the more you control and the more you must maintain.
Is SaaS cheaper than buying software outright?
Cheaper to start, more expensive to keep. There is no upfront licence cost and no server to buy, but the subscription never ends and the price typically rises at renewal. Over five to seven years a perpetual licence can cost less in total — which is why some categories, notably design and developer tools, still sell them.
Do you own your data in a SaaS product?
You own the data; the vendor holds it. What matters practically is whether you can export it in a usable format, how long they retain it after cancellation, and whether the export includes your configuration as well as your records. Check all three before you depend on the product.
What happens to your data if a SaaS company shuts down?
Typically you get a notice period to export, and anything not exported is deleted. There is usually no escrow and no obligation to keep the service running. This is the single largest practical risk of SaaS and the reason to keep periodic exports of anything you would struggle to recreate.
Sources & verification
Facts on this page were read from the sources below on the dates shown. Where a vendor does not publish a figure, we record it as not disclosed rather than estimating it.
- NIST Definition of Cloud Computing (SP 800-145) — checked 10 July 2026
Spotted something out of date? Email editorial@everyany.one and we will re-check it. Corrections are logged on the page.