Azure Functions vs AWS Lambda – Which is Better ? (Pros and Cons)

Azure Functions vs AWS Lambda – Which is Better? First thing both Azure Functions and AWS Lambda are offered by Microsoft and Amazon respectively. They bring the unlimited scale and high availability of cloud computing to both large and small organizations. 

Similarly these two services are alike in many ways. Primarily Azure Functions and AWS Lambda are based on the FaaS (Functions as a Service) model. Well, so FaaS is a serverless cloud service that allows users to build and run applications without managing the underlying infrastructure. Also, the two services support the same programming languages and have similar pricing models.

Still, Azure Functions and AWS Lambda have some significant differences that we’ll discuss below. 

Shall we start with the article Azure Functions vs AWS Lambda – Which is Better? Let’s dive in.

What is Azure Functions?

Interestingly Microsoft introduced Azure Functions in November 2016 at the Build 2016 Conference. The company had been offering PaaS (Platform as a Service) services for several years by then and was diving into the nascent serverless market. The service was Microsoft’s answer to AWS Lambda.

Primarily Azure Functions is a serverless computing service that allows users to run event driven programs without provisioning or managing infrastructure. In short, users get to run code on demand while scaling is taken care of automatically. As a result, development teams are able to focus on building and deploying functions and features.

With Azure Functions, you can run custom written code to connect multiple services in several programming languages, including PHP, Python, C#, and JavaScript.

Azure Functions Pros

  • Seamless integration with other Azure Services, including Notification Hubs, Event Grids, Service Bus, Event Hubs, and others. 
  • Supports different programming languages such as Java, JavaScript, Python, F#, C#, Node.js, and PHP.
  • Functions has an intuitive, browser based user interface. 
  • Runtime portability of applications so you can run them anywhere.
  •  Automated and flexible scaling.
  • Functions is an event driven platform so you can implement code triggered by third party services. 
  • Allows you to develop applications much faster compared to the traditional development process. 

Azure Functions Cons

  • Deploying, testing, and executing functions outside the Azure ecosystem can be challenging. 
  • You may struggle to figure out some simple tasks without the help of customer support. 

Now with this article Azure Functions vs AWS Lambda – Which is Better? is time to get to know AWS Lambda.

What is AWS Lambda

Launched in 2014, AWS Lambda is an event driven, serverless code execution platform owned by Amazon Web Services (AWS). Using the AWS machine architecture, Lambda allows you to create and deploy complex cloud based applications and run them at will.

Essentially, you just write and execute the code, and Lambda takes care of the rest. Some tasks you don’t have to worry about include booking server resources, keeping servers running optimally, scaling CPU, memory and RAM resources, patching security issues, and managing the operating system.

Moreover Lambda allows you to perform any computing task, including processing data streams, calling APIs, serving web pages, and integrating with other AWS services. Like Azure Functions, Lambda supports a variety of programming languages, including Java, C#, Ruby, Go, Python, and Node.js. Also, you have access to a Runtime API through which you can deploy code written in other languages.

AWS Lambda Pros

  • Easy to integrate Lambda with other AWS services. 
  • User friendly serverless computing tool. 
  • Scalable and highly flexible service.
  • Fast and seamless scalability. 
  • You can author directly using the WYSIWYG editor in console.
  • Monitor performance in real time using CloudWatch. 
  • Perform scheduled tasks with external event timers. 

AWS Lambda Cons

  • Not suitable for small projects. 
  • Can’t run long running workloads since execution time for functions/instances is capped at 15 minutes.  
  • Additionally Lambda costs can skyrocket if not well optimized.
  • You can’t run custom install software or packages on the Lambda environment. 
  • Vendor lock in.
  • Can only run up to 1000 requests concurrently. 

Now with Azure Functions vs AWS Lambda – Which is Better? but what are the differences?

Azure Functions vs AWS Lambda - The Differences

Available Hosting Plans

On one side with AWS, you can only run a serverless function by deploying it to AWS Lambda. Essentially, Amazon seeks to cover as many customer scenarios as possible with Lambda. You can build anything from a hobby website to an enterprise grade system on the service.

But Microsoft takes a different approach. So Azure Functions allows you to deploy functions to a full managed, pay per use Consumption plan. But at the same time, you can opt for other hosting options to run your code. These include KEDA (Kubernetes based event driven architecture), Docker container, premium plan and App Service plan.

Supported Programming Languages

Particularly with AWS Lambda it supports more programming languages than Azure Functions. They both support JavaScript, Java, PowerShell, Python, F#, and C#. In addition to these, Lambda also supports Go and Ruby.


Secondly AWS Lambda allows you to configure memory allocation to your functions. You can set it anywhere between 128MB to 3GB. The CPU power and cost are proportional to the memory you allocate. You’ll need to fiddle around with the settings to figure out the optimal configuration for your Lambda function. All Lambda instances run on Amazon Linux.

The Consumption plan on Azure Functions comes with a cookie cutter configuration of 1.5GB of memory and a single low profile virtual core. You can choose whether to run it on Linux or Windows. For the Premium plan, you get multiple instance sizes with up to four vCPUs and 14GB of RAM. You pay a fixed hourly cost for the reserved capacity.


Alternatively Azure Functions offers both local and remote debugging. Just hit the “F5” key in Visual Studio to start. For AWS Lambda, debugging is only available locally.

Concurrency and Isolation

Concurrency refers to the number of requests your function is serving at the same time. Well both Azure Functions and AWS Lambda support concurrency and can run thousands of executions simultaneously.

Remember AWS Lambda reserves a separate instance for each execution. Each instance has its own pool of memory and CPU cycles. As a result, performance is stable and predictable.

Similarly Azure Functions assigns multiple concurrent executions to the same virtual environment. The advantage of this setup is that it maximizes resource usage. For instance, when one execution is waiting for a response, resources are allocated to other executions. Unfortunately, this can negatively affect processing time and overall performance.


Pricing for serverless services is based on a resource usage (pay-per-use) model. Likewise Azure Functions and AWS Lambda have two cost components:

  • Pay per call.
  • Pay per GB*seconds (based on consumed memory and execution time).

The two services are priced the same way starting from $0.20 per one million executions and $16 per 1 million GB-s. You get 400,000 GB-s and 1 million executions for free. Even then, there are some differences in the cost:

On Lambda you pay for full provisioned memory for each instance while you pay for actual average memory consumed for executions.
Since executions on Azure Functions share instances, the cost of memory isn’t charged multiple times. This can lead to considerable cost savings depending on your workload.

CPU profiles differ between the two services, which often leads to different costs for similar workloads. For both services, you must pay for at least 128MB and 100s for each execution. On Azure Functions the time is rounded up to the nearest 1ms while on AWS Lambda it’s rounded up to the nearest 100ms. 

HTTP Integration

Significantly Azure Functions comes with HTTP Integration and an HTTP end point out of the box. Even better, you don’t pay to use this service. You can use HTTP triggers to incorporate webhooks into your system and build serverless APIs.

With AWS Lambda, you need an API gateway to listen to HTTP traffic. Alternatively, you can integrate with Elastic Load Balancing (ELB) for a more cost effective solution.

Scalability and Performance

Specifically AWS Lambda comes with dynamic scaling that allows you to chain new features and helps incorporate custom serverless functions as a service. Due to the robust auto scaling feature, performance is seamless and your functions experience minimal latency. So the AWS Lambda is a great choice if you need rapid scaling and the capacity to handle massive workloads.

Scaling on Azure Functions is managed by the Azure Function Scale Controller. The controller checks the queued executions and issues peek commands. If there are latencies, virtual machines are added until performance gets to the desired level.


What are Serverless functions? In nutshell they are essentially small blocks of disjointed code that do just one thing. To build an application, you have to make your functions work together in a synchronized workflow. This is where orchestration comes in.

Significantly Azure and AWS come with dedicated services to deal with workflow orchestration – Azure Logic Apps and AWS Step Functions. These services allow you to solve complex tasks using independent functions as steps within a workflow.

Secondly AWS Step Functions enable you to coordinate multiple AWS offerings into serverless workflows. Use the drag and drop visual editor on Step Functions to assemble individual functions into a unified workflow. For each step of the workflow, Step Functions manages the input, output, retries and error handling. As a result, you can focus on higher value business logic for your applications.

Likewise the Step Functions, Azure Logic Apps is a fully managed integration tool with a visual designer to help users model their workflows. You can create applications via the Azure Portal, Visual Studio (2015 and later), or in templates from Microsoft.

While Azure Logic Apps and AWS Step Functions are largely similar, one of the outstanding features of Logic Apps is that it contains prebuilt connectors that can push and pull data from your applications. You can deploy Azure Functions from GitHub, zip packages, Bitbucket, Atlassian, or an external repository. In contrast, you can only deploy source code from zip packages with AWS Lambda.

Library in Azure Functions  (Azure Durable Functions) that allows you to bring workflow orchestration abstractions to code.  

Thank you for reading Azure Functions vs AWS Lambda – Which is Better?

Azure Functions vs AWS Lambda - Which is Better ? Conclusion

Summing up both AWS Lambda and Azure Functions are very similar services. So it’s the subtle differences that inform your choice between the two.

Generally, Azure Functions treats the “application” as the unit. Configuration files are allocated to the whole application while resources apply to a function app. Lambda, on the other hand, takes a more granular approach where every function is largely independent of the other.

In most cases, your choice will depend on your application and the constraints of each service. But since the differences aren’t too stark, the decision is often down to your familiarity with the service.

Avatar for Richard Kanyoro
Richard Kanyoro

The world’s biggest problems can be solved by progressively solving the little ones. I write to help people solve the “little” tech problems they face.

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