What is Azure Functions?
Azure Functions runs event-driven application code through several Azure hosting options. Flex Consumption, Premium and other arrangements have different scaling, runtime and billing behaviour, so the hosting choice is part of the product decision.
Who is Azure Functions for?
Development teams selecting an Azure function-hosting model around event volume, response time and deployment requirements.
The hosting plan is part of the design
Azure Functions provides event-driven code execution with service triggers and bindings. Microsoft’s hosting guidance recommends Flex Consumption for new serverless function apps, while documenting other options for different requirements.
Specify the event source, workload pattern and expected response time before selecting a plan. For an interactive request, distinguish the time needed to respond from any longer work that can be completed asynchronously. Compare Lambda and Cloud Run using the same event and completion requirements.
Azure Functions features
The core capabilities to consider for your workflow.
- Event triggers and service bindings
- Plan-dependent serverless scaling
- Function orchestration and backend workflows
Azure Functions pricing
Hosting-plan pricing; conditional grants
Choose the hosting option first, then estimate executions, memory-duration usage and any always-ready capacity. Include the required storage, networking and related services in the architecture budget.
Calculate the cost of your quote →Free access & evaluation
Applicable on-demand hosting options include monthly free grants. Their scope depends on the plan; always-ready billing and connected services should not be assumed to be covered.
Before you choose Azure Functions
The chosen hosting plan determines scaling, cost and available capabilities.
A longer function timeout does not remove the documented HTTP response limit.
Flex Consumption always-ready usage has different billing from on-demand free grants.
Check idle capacity and long-running requests separately
The cost guidance separates Flex Consumption on-demand use from always-ready capacity. Always-ready billing has no free grants. A quoted execution allowance should not be applied indiscriminately to every hosting arrangement.
Microsoft’s scaling documentation explains cold starts and plan-specific mitigation. Define the latency the application can tolerate and what persistent capacity would cost. Also review the documented HTTP response boundary: a longer function execution setting does not remove the default load-balancer response timeout. For longer tasks, assess an asynchronous design rather than assuming a synchronous connection can remain open indefinitely.
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Azure Functions FAQs
Which Azure Functions hosting plan is recommended for new serverless apps?
Microsoft’s reviewed hosting guidance recommends Flex Consumption for new serverless function apps. Select the option against the workload’s networking, runtime and scaling requirements.
Do Flex Consumption free grants cover always-ready instances?
No. Microsoft’s cost guidance says there are no free grants in always-ready billing. It includes baseline capacity as well as execution-related costs.
Why can an Azure HTTP function time out after 230 seconds despite a longer function timeout?
The hosting documentation describes a 230-second HTTP response limit caused by the default Azure Load Balancer idle timeout. It recommends asynchronous patterns for longer work.
What is a cold start in Azure Functions?
After an idle app scales to zero, its next request can experience added startup latency. The hosting plan determines the available mitigation, such as always-ready or prewarmed capacity.
Do all Azure Functions hosting options scale and bill the same way?
No. Flex Consumption, Premium, Dedicated and Container Apps arrangements have different resource, scaling and billing models. The hosting choice must be included in the estimate.