Does an empty plan, or one with only stopped apps, still cost money?

Yes, unless it is on the Free tier. On dedicated tiers each instance in the plan is billed however many apps it hosts, and stopped apps are still charged. Delete apps and plans you no longer use, or move the plan to the Free tier.

Do deployment slots add to a client's bill?

Slots have no separate charge, but they are not free capacity. They run on the same instances as their plan by default, and an active slot counts as an active app competing for those resources, so forgotten slots use headroom you are already paying for.

Reservations or a savings plan for client App Service estates?

It depends on how stable the footprint is. Reservations fix a size and region for deeper discounts on steady usage. A savings plan commits to an hourly spend that applies across eligible services and regions, including App Service, but cannot be cancelled or refunded.

Coverage

App Service cost optimisation for MSPs

App Service bills for the instances an App Service plan reserves, prorated to the second, not for the apps running on it. Spend is wasted when plans sit on an oversized tier, host nothing at all, or scale out for a peak and never scale back in.

13

automated finders for App Service

Read-only, across every connected client tenant, tied to real billing data.

Modernise
Remove unused
Rightsizing
Scaling
Off-hours schedules

Where App Service spend goes to waste

The main cost levers Microsoft documents for App Service, and the ones an MSP should check across every client.

Delete or downgrade empty plans

A plan keeps reserving, and billing for, its instances after every app on it has been removed. Delete plans that no longer host anything, or move any you need to keep to the Free tier so the charges stop. ^[2]

Consolidate compatible apps

On dedicated tiers you pay for each instance in a plan, not each app, so hosting compatible apps together can reduce the instances you fund. Check the plan has spare capacity first, and keep resource-hungry apps or apps that need to scale independently on their own plan. ^[3]

Move older plans to Premium v3

Premium v3 has faster processors and twice the memory-to-core ratio of Premium v2, so the same workload may run on fewer instances. If the current deployment unit does not offer Premium v3, the app needs redeploying to a new plan first. ^[4]

Autoscale with firm limits and scale-in rules

Every scaled-out instance is billed while it is allocated. A plan that grows for a peak and never shrinks keeps paying for idle capacity, so set minimum and maximum instance counts and add rules that remove instances when demand falls. ^[1]

Reserve the steady baseline

Where a client will run a known minimum of Premium v3 instances for a year or more, one- or three-year reservations can cut the cost per instance by as much as 55%. Size reservations to that baseline, because unused reserved instances are still paid for. ^[5]

Keep App Service Environment for real isolation needs

App Service Environment v3 gives dedicated, network-isolated hosting for compliance-driven or very large workloads. An empty environment is still billed as if one Windows I1v2 instance were running, so retire unused environments. ^[6]

How Cerberus Cloud covers App Service

Cerberus Cloud runs 13 automated finders for App Service across every connected client tenant. Each one ties a technical signal to real billing data, so findings arrive with an estimated recoverable value, ranked by impact, effort and risk, with evidence and remediation scripts for your engineers to review.

Access is read-only, so nothing changes in a client environment until your team decides it should. See how it works or the multi-tenant portfolio view.

Modernise
Remove unused
Rightsizing
Scaling
Off-hours schedules

Frequently asked questions

Does an empty plan, or one with only stopped apps, still cost money?: Yes, unless it is on the Free tier. On dedicated tiers each instance in the plan is billed however many apps it hosts, and stopped apps are still charged. Delete apps and plans you no longer use, or move the plan to the Free tier.
Do deployment slots add to a client's bill?: Slots have no separate charge, but they are not free capacity. They run on the same instances as their plan by default, and an active slot counts as an active app competing for those resources, so forgotten slots use headroom you are already paying for.
Reservations or a savings plan for client App Service estates?: It depends on how stable the footprint is. Reservations fix a size and region for deeper discounts on steady usage. A savings plan commits to an hourly spend that applies across eligible services and regions, including App Service, but cannot be cancelled or refunded.

See App Service findings on a sample portfolio

A 15-minute walkthrough: tenant connection, prioritised findings, remediation scripts and savings history.

Book a Walkthrough All coverage

Sources

Last checked 15 October 2026. Product details change; tell us if something here is out of date.

All 15 coverage families