SaaS or GaaS? How to tell which one your product should be

Every founder we have spoken to this year has asked some version of the same question: is SaaS finished now that AI agents can do the work? Our answer is no, but the question is a good one, because the line between the two decides how you price, what your margins look like and what can go wrong.

The one-sentence difference

SaaS sells access to a tool. Your customer logs in and their team does the work inside it. GaaS, AI agents as a service, sells the outcome. The invoices get matched, the tickets get answered, the forms get processed, and a person checks and approves.

That sounds like a small change in wording. It changes almost everything behind it.

What changes when you sell the outcome

• Pricing moves from seats to work done. Per invoice, per resolved ticket, per processed application. Customers like this because they pay for results; it also means your revenue now moves with their volume.
• Your costs move too. Every task an agent runs costs you model calls. A SaaS seat costs roughly the same whether it is used or not; an agent task does not. If you do not measure cost per task from day one, you can grow your way into a loss.
• You own more of the risk. When software is a tool, a mistake is the user’s. When software does the job, the mistake is yours. That is why approvals, logs and limits matter more in GaaS than they ever did in SaaS.

Why most products need both

Agents still need somewhere to live. They need accounts, permissions, billing, a record of what they did and a screen where a person approves the work. That is a SaaS product. In practice the strongest products we see are SaaS on the outside, with agents doing the repetitive work inside: the tool for the parts that need judgement, the agent for the parts that do not.

SaaS is the system of record. The agent is the employee who works in it.

Four questions to decide your split

• Is the work repetitive and checkable? Matching, sorting, extracting and drafting are good agent work. Negotiating, designing and deciding policy are not.
• Can a person check the result faster than they could do it? If checking takes as long as doing, the agent saves nothing.
• What does a mistake cost? If the answer is "a refund and an apology", automate more. If it is "a regulator", keep a person in the loop.
• Can you measure the outcome? GaaS pricing only works if you and the customer agree on what counts as a finished job.

Where to start

If you already run a SaaS product, do not rebuild it. Pick the one task your customers complain about most, build an agent for that task inside the product, and charge for it separately. You learn what customers will pay for an outcome without betting the whole business on it.

If you are starting from scratch, build the SaaS core first: accounts, data separation between customers, billing and an approval screen. The agents plug into that, not the other way round.