What can a company rent as AI as a service?
Three layers, from raw to finished. At the bottom sits compute: GPUs by the hour from a cloud or a neocloud. In the middle sit models behind an API, from a frontier lab or an inference provider that hosts open-weight models. At the top sit packaged capabilities: speech recognition, document extraction, or a whole AI agent platform. The pattern mirrors the classic cloud split into infrastructure, platform and software that NIST defined in SP 800-145 (NIST, September 2011, read 9 November 2026). The higher the layer you rent, the faster you start and the less you control.
AI as a service vs SaaS: what’s the difference?
| SaaS | AI as a service | |
|---|---|---|
| What you rent | A finished application | A capability: a model, an API, a runtime |
| Typical price unit | Seat per month | Token, call, minute or seat |
| Who builds the workflow | The vendor | You, or a partner |
| Output | Predictable | Probabilistic, needs checking |
A SaaS product works the day you log in; an AI service works the day you connect it. That gap is where most of the effort, and most of the value, sits.
What does a buyer still own when renting AI?
The data going in, the integration into real systems, the checks on what comes out, and the decision about what the AI may do alone. Renting the model does not rent you the human in the loop, the audit trail or the evaluation that proves the system works on your cases. You can outsource the model, not the accountability. Most failed AI purchases bought a capability and assumed they had bought an outcome.
How do you avoid lock-in with AI as a service?
Keep the parts that encode your business on your side: prompts, evaluation sets, workflow logic and logs. Put a thin gateway between your code and the vendor so a model swap is a configuration change, as described under AI vendor lock-in. Price the exit before you sign: what it costs to move your data, retrain your staff and rerun your evals elsewhere. For the broader decision, see build vs buy for AI and the list of AI vendors businesses actually pay for.