Practical guide · verified against the real thing
Which cloud service model fits me? — SaaS, PaaS, IaaS, serverless or self-hosted
In one line: SaaS, PaaS, IaaS, serverless or self-hosted: six questions, one recommendation, reasoning shown — with the real cost shape of each rung. Runs on-device.
SaaS, PaaS, IaaS, serverless, or self-hosted — five words that decide who does the work. The cloud isn’t one thing; it’s a ladder of “how much do you want to run yourself.” Climb it one rung too high and you’re paying a provider to do a job you’d never notice; one rung too low and you’re the on-call sysadmin for a server you didn’t want. Six questions place you on the right rung — and show which answers drove the call.
Why the questions are shaped this way
The whole ladder is one question repeated: who does the work? SaaS means the vendor runs everything including the software; PaaS runs the servers while you keep the code; IaaS rents raw machines; serverless rents outcomes per request; self-hosting keeps the work (and the control) in your building. So the tool asks what you’re running, who can maintain it, how the load behaves, whether buying beats building, what it may hold, and what you can actually spend. Budget moves you along the rung you’re on — it never changes which rung is honest.
The five rungs, and the shape of their cost
| Rung | Who does the work | Cost shape (directional) | The classic mistake |
|---|---|---|---|
| SaaS | The vendor, all of it | Per-seat or per-month subscription | Building what you could rent — pricing models explained |
| PaaS | Platform runs servers; you ship code | Usage-based, usually modest for small apps | Ignoring egress and build-minute meters |
| IaaS | You run the OS and up | Hourly/monthly, predictable if steady | Paying for idle capacity month after month |
| Serverless | Nobody, until a request arrives | Per-invocation; $0 when quiet | Uncapped concurrency — why cloud bills spike |
| Self-hosted | You, entirely | Hardware up front + your time forever | Underpricing your own labour — when it’s worth it |
Provider choice comes after the rung: AWS vs Azure vs GCP, choosing honestly. If the rung is SaaS, read lock-in and data portability before signing, and keep the whole cloud & hosting cluster one click away.
What this tool deliberately does not do
- It doesn’t pick a provider. Rung first, provider second — every “best cloud” list online skips that order.
- It doesn’t quote prices. The shapes above are directional; your workload’s maths decides. The 3-year cost method applies to cloud too.
- It doesn’t phone home. No analytics on your answers, no storage, no network calls.
Sources
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