This document outlines the various limits and constraints associated with Azure Functions. Understanding these limits is crucial for designing scalable, reliable, and cost-effective serverless applications.
These limits apply broadly across different hosting plans and regions.
| Limit | Description | Default Value | Notes |
|---|---|---|---|
| Function App | Maximum number of function apps per Azure subscription. | 100 (soft limit) | Can be increased by contacting Azure support. |
| Function Runtime | Maximum memory that a single function instance can consume. | 1.5 GB (Consumption Plan) | Higher limits available on App Service plans. |
| Execution Timeout | Maximum duration a function can run. | 5 minutes (Consumption Plan default) | Configurable up to 10 minutes on Consumption Plan. Unlimited on Premium/App Service plans (with default of 30 mins). |
| HTTP Trigger Request Body Size | Maximum size of the request body for HTTP triggered functions. | 100 MB | Consider asynchronous patterns for larger payloads. |
| Deployment Size | Maximum size of a deployed function app package. | 1 GB | For zipped deployments. |
Ideal for event-driven workloads, scales automatically, and you only pay for execution time.
| Limit | Description | Value |
|---|---|---|
| Execution Duration | Maximum execution time per function invocation. | Configurable up to 10 minutes. |
| CPU | Available CPU resources per instance. | Limited and shared across function apps. |
| Memory | Available memory per instance. | 1.5 GB. |
| Cold Start | Latency experienced when a function is invoked after a period of inactivity. | Can occur, varies by region and workload. |
| Concurrency | Number of concurrent executions per function. | 600 (total for the plan), 200 (per function). |
Offers pre-warmed instances, VNet connectivity, and longer runtimes without cold starts.
| Limit | Description | Value |
|---|---|---|
| Execution Duration | Maximum execution time per function invocation. | Default 30 minutes, configurable up to unlimited. |
| CPU/Memory | Dedicated resources per instance. | Varies based on instance size (EP1, EP2, EP3). |
| Pre-warmed Instances | Ensures instances are always ready. | Configurable. |
| VNet Integration | Connect to private networks. | Supported. |
Run Functions on dedicated VMs, offering full control over resources and predictable pricing.
| Limit | Description | Value |
|---|---|---|
| Execution Duration | Maximum execution time per function invocation. | Default 30 minutes, configurable up to unlimited. |
| CPU/Memory | Dedicated resources based on the App Service plan tier. | Varies by tier (F1, D1, B1, etc.). |
| Instance Count | Number of instances for scaling. | Configurable based on App Service plan scaling rules. |
Specific limits related to event sources and data connectors.
| Trigger/Binding | Limit | Notes |
|---|---|---|
| Azure Storage Queue | Message visibility timeout. | 7 days. |
| Azure Service Bus | Message lock duration. | 5 minutes (default), configurable. Max: 30 minutes. |
| Azure Event Hubs | Event ingestion rate. | Depends on the hub's throughput units. |
| HTTP Trigger | Connection timeout. | 230 seconds (for client requests). |
Always refer to the official Azure Functions documentation for the most up-to-date and comprehensive information.