Overview of the Azure Functions Free Tier
Azure Functions offers a powerful and cost-effective way to run small pieces of code, or "functions," in the cloud. The Free tier is designed to help you get started, experiment, and even run small-production workloads without incurring costs, within certain limits.
Key Benefits of the Free Tier:
- Cost Savings: Execute code without worrying about upfront costs or minimum charges for many use cases.
- Scalability: Functions automatically scale based on demand, even within the free tier, ensuring your application remains responsive.
- Event-Driven Architecture: Easily build event-driven applications by triggering functions from various Azure services and external events.
- Language Support: Develop in your preferred language, including C#, F#, Java, JavaScript, PowerShell, Python, and TypeScript.
Free Tier Limits and Details
The Free tier is part of the Consumption plan. Here are the typical limits:
Monthly Entitlements:
- Execution Time: Up to 1 million executions per month.
- Execution Time (GB-seconds): Up to 400,000 GB-seconds of resource consumption per month.
What is a GB-second? A GB-second is a unit of measure for the resources consumed by your function executions. It's calculated by multiplying the memory allocated to your function (in GB) by the time your function runs (in seconds). For example, a function that runs for 1 second with 1 GB of memory allocated consumes 1 GB-second.
Important Considerations:
- These limits are reset monthly.
- Exceeding these limits will automatically transition your functions to the standard Consumption plan pricing.
- The Free tier is ideal for development, testing, and low-traffic production scenarios.
- For high-traffic production applications or those requiring guaranteed performance, consider other App Service plan options.
Tip: Monitor your function's resource consumption in the Azure portal to stay within the free tier limits. You can set alerts to notify you if you approach the limits.
How to Use the Free Tier
When you create an Azure Functions app and choose the Consumption plan, you are automatically provisioned with the Free tier entitlements. There's no special configuration needed to "enable" the free tier; it's the default behavior of the Consumption plan up to the specified limits.
Getting Started:
- Create an Azure Account: If you don't have one, sign up for a free Azure account.
- Create an Azure Functions App: Use the Azure portal, Azure CLI, or Visual Studio Code to create a new Functions app. Select the "Consumption" hosting plan.
- Develop and Deploy: Write your function code in your preferred language and deploy it to your Functions app.
- Monitor: Keep an eye on your function executions and resource usage via the Azure portal's monitoring tools.
Example Scenario
Let's say you have a small web API that responds to an average of 10,000 requests per day. If each request triggers a function that runs for 500 milliseconds (0.5 seconds) and is allocated 128 MB (0.125 GB) of memory:
- Daily Executions: 10,000 executions
- Monthly Executions: 10,000 * 30 = 300,000 executions (well within the 1 million limit)
- GB-seconds per execution: 0.125 GB * 0.5 s = 0.0625 GB-seconds
- Monthly GB-seconds: 300,000 executions * 0.0625 GB-seconds/execution = 18,750 GB-seconds (well within the 400,000 GB-seconds limit)
In this scenario, your functions would run entirely within the Free tier, incurring no cost.
Beyond the Free Tier
While the Free tier is generous, it's essential to understand what happens when you exceed the limits:
- Your functions will continue to run, but you will be billed according to the standard Azure Functions Consumption plan rates.
- You can view current pricing details on the Azure Functions Pricing page.
For more predictable costs, higher performance, or features like VNet integration, consider:
- Premium Plan: Offers enhanced performance, VNet connectivity, and no cold starts.
- Dedicated (App Service) Plan: Run your functions on dedicated VMs for consistent performance and predictable pricing.