This tool is a starting point, not a final answer. It applies Microsoft's published decision criteria to your inputs. Real decisions may also involve team skill, existing contracts, regional availability, Azure agreements, or organisational policy. Always validate the recommendation with your team or architect before committing.
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Scope: This tool covers the hosting plan decision only — not trigger types, Durable Functions patterns, or runtime versions. A follow-up tool covering trigger and execution model selection is planned.
If none of your requirements are unusual — no Windows dependency, no custom containers, no existing App Service Plan to reuse — Flex Consumption is Microsoft's current recommended starting point for new function apps.
- ✓Pay-as-you-go billing — no cost when idle
- ✓VNET support included, unlike standard Consumption
- ✓Lower cold starts than Consumption, with the option to eliminate them via pre-provisioned instances
- ✓Actively developed — this is where Microsoft is investing, not a legacy plan
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Azure Functions scale and hosting
The primary Microsoft reference — covers all hosting options, scaling behaviour, OS support, and feature comparison tables.
learn.microsoft.com
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Flex Consumption plan — deep dive
Pre-provisioned instances, VNET support, memory configuration, concurrency settings, and billing detail for the Flex plan.
learn.microsoft.com
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Functions Premium plan — deep dive
SKU options (EP1–EP3), pre-warmed instances, VNET integration, and when to choose Premium over Flex Consumption.
learn.microsoft.com
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Migrate from Consumption to Flex
Microsoft's official migration guide — Consumption (Linux) is retired. If you're on it, here's how to move to Flex Consumption.
learn.microsoft.com
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Azure Functions pricing
Current pricing for all hosting plans — execution costs, GB-second rates, instance costs, free tier breakdown, and the pricing calculator.
azure.microsoft.com
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Flex Consumption samples (GitHub)
Official Azure sample repo for Flex Consumption — real working code across multiple languages, triggers, and deployment patterns.
github.com / Azure-Samples