/azure-functions

name: azure-functions
description: Expert knowledge for Azure Functions development including troubleshooting, best practices, decision making, architecture & design patterns, limits & quotas, security, configuration, integrations & coding patterns, and deployment. Use when building trigger-based apps with Durable Functions, containers, CI/CD, VNet security, or scaling controls, and other Azure Functions related development tasks. Not for Azure App Service (use azure-app-service), Azure Logic Apps (use azure-logic-apps), Azure Container Apps (use azure-container-apps), Azure Kubernetes Service (AKS) (use azure-kubernetes-service).
compatibility: Requires network access. Uses mcp_microsoftdocs:microsoft_docs_fetch or fetch_webpage to retrieve documentation.
metadata:
  generated_at: "2026-08-09"
  generator: "docs2skills/1.0.0"

Azure Functions Skill

This skill provides expert guidance for Azure Functions. Covers troubleshooting, best practices, decision making, architecture & design patterns, limits & quotas, security, configuration, integrations & coding patterns, and deployment. It combines local quick-reference content with remote documentation fetching capabilities.

How to Use This Skill

> **IMPORTANT for Agent**: Use the **Category Index** below to locate relevant sections. For categories with line ranges (e.g., `L35-L120`), use `read_file` with the specified lines. For categories with file links (e.g., `[security.md](security.md)`), use `read_file` on the linked reference file

> **IMPORTANT for Agent**: If `metadata.generated_at` is more than 3 months old, suggest the user pull the latest version from the repository. If `mcp_microsoftdocs` tools are not available, suggest the user install it: [Installation Guide](https://github.com/MicrosoftDocs/mcp/blob/main/README.md)

This skill requires **network access** to fetch documentation content:

• **Preferred**: Use `mcp_microsoftdocs:microsoft_docs_fetch` with query string `from=learn-agent-skill`. Returns Markdown.
• **Fallback**: Use `fetch_webpage` with query string `from=learn-agent-skill&accept=text/markdown`. Returns Markdown.

Category Index

| Category | Lines | Description | |----------|-------|-------------| | Troubleshooting | L37-L60 | Diagnosing and fixing Azure Functions runtime and configuration issues (AZFD/AZFW codes), storage and secrets errors, timers, worker runtime mismatches, networking, and Node.js/Python-specific problems. | | Best Practices | L61-L79 | Guidance on coding, performance, reliability, error handling, DI, idempotency, and language-specific (C#, Java, Node.js, Python) best practices for Azure Functions. | | Decision Making | L80-L101 | Guidance on choosing Azure Functions hosting/runtime models, comparing costs, and planning migrations (between plans, .NET models, runtime versions, AWS Lambda, Express.js, and related extensions). | | Architecture & Design Patterns | L102-L107 | Running Functions in Linux containers, Durable Functions design with Azure Storage, and hosting Functions on Azure Container Apps for scalable, container-based architectures. | | Limits & Quotas | L108-L114 | Scaling and concurrency limits for Functions: how triggers scale, configuring max concurrent executions, and using target-based scaling to control throughput and resource usage. | | Security | L115-L129 | Securing Azure Functions apps: encryption at rest, secure storage, keys and secrets, private endpoints/VNet, networking access controls, managed identity for SQL, and App Service security features. | | Configuration | L130-L172 | Configuring Azure Functions behavior, runtime, triggers/bindings, networking, monitoring/tracing, local dev tools, and app settings (incl. Cosmos DB, SQL, Event Hubs, OpenAI, NAT, Elastic, versions). | | Integrations & Coding Patterns | L173-L278 | How to connect Functions to external services (storage, databases, messaging, AI/OpenAI, MCP/Dapr, SignalR/Web PubSub) using triggers/bindings and integration patterns across languages. | | Deployment | L279-L310 | Deploying and hosting Azure Functions: provisioning plans with IaC tools, containers/Kubernetes, CI/CD (GitHub/Azure Pipelines), slots, zip/package deploy, migrations, and language‑specific build/publish. |

Troubleshooting

| Topic | URL | |-------|-----| | Resolve AZFD0001 missing AzureWebJobsStorage setting | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0001 | | Fix AZFD0002 invalid AzureWebJobsStorage value | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0002 | | Troubleshoot AZFD0003 StorageException fetching diagnostics | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0003 | | Resolve AZFD0004 Azure Functions host ID collision | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0004 | | Fix AZFD0005 external startup exception in Functions | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0005 | | Handle AZFD0006 expiring SAS token warnings | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0006 | | Resolve AZFD0007 too many secrets backups | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0007 | | Fix AZFD0008 archive-tier Blob secrets repository | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0008 | | Resolve AZFD0009 unable to parse host.json | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0009 | | Fix AZFD0010 TZ/WEBSITE_TIME_ZONE on Linux Consumption | https://learn.microsoft.com/en-us/azure/azure-functions/errors-diagnostics/diagnostic-events/azfd0010 | | Resolve AZFD0011 missing FUNCTIONS_WORKER_RUNTIME | https://learn.microsoft.com/en-us/azure/azure-functions/errors-