Independent comparison for serverless function platforms. Updated May 2026.
Quick verdict: Choose AWS Lambda for the broadest event-source integration ecosystem (200+ AWS services), provisioned concurrency, SnapStart for Java, and the deepest production tooling. Choose Azure Functions for tight integration with Microsoft 365, Power Platform, and the .NET ecosystem, plus Durable Functions for orchestration scenarios where stateful workflows matter. The differentiator is AWS ecosystem breadth vs Microsoft estate alignment and stateful orchestration.
| Criteria | AWS Lambda | Azure Functions |
|---|---|---|
| Runtimes | Node.js, Python, Java, .NET, Ruby, Go, custom | .NET, Node.js, Python, Java, PowerShell, custom |
| Hosting Plans | On-demand only | Consumption, Premium, Dedicated, Flex Consumption |
| Max Execution Time | 15 minutes | 10 minutes (Consumption), unlimited (Premium / Dedicated) |
| Max Memory | 10 GB | 14 GB (Flex Consumption) |
| Cold Start Optimisation | SnapStart, provisioned concurrency | Premium plan with pre-warmed instances |
| Pricing — Free Tier | 1M requests + 400K GB-seconds free / month | 1M executions + 400K GB-seconds free / month |
| Pricing — Per Request | $0.20 per 1M requests | $0.20 per 1M executions |
| Stateful Orchestration | Step Functions (separate service) | Durable Functions (built-in) |
| Event Sources | 200+ AWS services, EventBridge | Azure services, Event Grid, Service Bus |
| Best For | Event-driven AWS architectures | Microsoft estate, .NET workloads, orchestration |
AWS Lambda is the original commercial serverless platform and remains the most feature-complete. Lambda supports a broad range of runtimes and is triggered by over 200 AWS services through event source mappings or EventBridge. Provisioned concurrency keeps instances warm to eliminate cold start. SnapStart for Java dramatically reduces cold start by restoring instances from cached snapshots. Lambda Function URLs provide direct HTTPS access without API Gateway. The Lambda ecosystem in CloudWatch, X-Ray, IAM, and the broader AWS observability stack is mature and well-integrated.
Azure Functions offers a richer set of hosting plans than Lambda. The Consumption plan is the closest equivalent to Lambda — pay per execution with cold starts. Premium plan provides pre-warmed instances with no cold start, dedicated VM access, and longer execution times. Dedicated plan runs Functions on dedicated App Service compute. Flex Consumption (generally available 2024) combines consumption pricing with reduced cold start and longer maximum execution. Azure Functions also includes Durable Functions natively — a stateful programming model for orchestrating long-running workflows, eliminating the need for a separate orchestration service like AWS Step Functions for many use cases.
Both platforms support the major runtime languages. Azure Functions is the natural choice for .NET workloads with first-class C# support and direct integration with Visual Studio tooling. Lambda's .NET support is solid but Azure's .NET integration is deeper. For Python, Node.js, and Java, both platforms are comparable. Browse additional serverless options in the cloud infrastructure category.
Lambda and Azure Functions Consumption plan are priced identically at $0.20 per 1M requests and $0.0000166667 per GB-second of execution. The free tier on both platforms is 1M requests / executions plus 400,000 GB-seconds monthly. For typical low-traffic applications, costs are minimal on both platforms. Azure Premium plan adds a per-vCPU-second cost that delivers pre-warmed instances — typical pricing is $0.173 per vCPU-second of pre-warmed instance time.
For high-volume production workloads, total cost depends on which hosting plan is used. Lambda's provisioned concurrency adds fixed cost per provisioned instance. Azure Premium plan provides similar functionality with different pricing dimensions. For applications requiring no cold start at scale, both platforms produce broadly comparable total bills. AWS Lambda compute savings plans can reduce costs for predictable workloads.
Choose AWS Lambda if your event-driven architecture spans multiple AWS services, you need the broadest ecosystem of event sources, or your team has existing AWS expertise and tooling. Lambda is the right choice for SnapStart-optimised Java workloads, applications using the 200+ AWS service event integrations, and customers standardising on AWS as the primary cloud.
Choose Azure Functions if your applications integrate with Microsoft 365, Power Platform, Dynamics 365, or the .NET ecosystem. Azure Functions also fits applications requiring Durable Functions for stateful orchestration without a separate workflow service, and customers needing the flexibility of multiple hosting plans (Consumption, Premium, Dedicated) to match different workload patterns within the same platform.