Remote Debugging Azure Functions: 7 Techniques

Need to debug your Azure Functions running in the cloud? Here's a quick guide to remote debugging:

The 7 key debugging methods:

1. Visual Studio Debugger - Connect directly to running functions
2. Application Insights - Monitor performance and errors
3. Snapshots - Capture function state at specific points
4. Live Metrics Watch - Track real-time performance
5. VS Code Setup - Debug using VS Code
6. Kudu Console - Access logs and processes
7. Cloud Explorer - Manage debug settings

Method	Best For	Setup Time
VS Debugger	Step-by-step code inspection	5-10 min
App Insights	Production monitoring	15-20 min
Live Metrics	Real-time issue detection	10-15 min
Kudu Console	Log inspection	2-5 min

Quick setup:

1. Install Visual Studio 2019+ with Azure Tools
2. Enable remote debugging in Azure Portal
3. Connect to w3wp.exe process
4. Add breakpoints where needed

Important: Only use remote debugging in production when absolutely necessary. Turn it off after debugging to avoid performance impacts and security risks.

This guide shows you how to:

• Set up your debug environment
• Connect to running functions
• Monitor performance
• Fix common issues
• Keep your debugging secure

Related video from YouTube

Getting Started

Here's what you need for Azure Functions remote debugging and how to set it up:

Tools You Need

Tool	Purpose	Required Version
Visual Studio	Main debugging environment	VS 2019 or later
VS Code	Alternative debugging option	Latest version with Azure Tools Extension
Azure Functions Core Tools	Local development and testing	v4.x
Azure Functions Extension	VS Code integration	Latest version

Basic Setup Steps

1. Install Azure Functions Core Tools

For Windows, download and run the MSI installer for v4.x (64-bit).

For macOS, run these commands:

brew tap azure/functions
brew install azure-functions-core-tools@4

2. Set Up Visual Studio

Head to Debug -> Options and switch off these settings:

• "Require source files to exactly match the original version"
• "Enable Just My Code"

3. Create Your Project

func init MyProjFolder --worker-runtime javascript --model V4
func new --template "Http Trigger" --name MyHttpTrigger

Security Setup

Setting	Action	Note
Remote Debug	Enable in Azure Portal	Auto-disables after 48 hours
Process Access	Select w3wp.exe	Required for attaching debugger
Debug Mode	Use Debug configuration	Not Release mode
Port Access	Check port 4024	Must be open for connections

Keep Your Debug Sessions Safe:

• Switch off remote debugging when done
• Don't leave breakpoints active too long
• Store local.settings.json safely
• Test storage with Azurite emulator

To debug, connect to w3wp.exe remote process in Visual Studio. Enter your Azure Function App URL and pick Managed (.Net Core, .NET 5+) in the Attach to Process window.

Important: Only use remote debugging outside of production unless you have NO other option.

7 Main Debug Methods

Here's how to debug Azure Functions when you're not on the same machine:

Using Visual Studio Debugger

Want to debug your Azure Function right from Visual Studio? Here's how:

Do This	Like This	Notes
Open Debug	Debug -> Attach to Process	First step
Pick Connection	Microsoft Azure App Service	Choose from dropdown
Type Address	yourapp.azurewebsites.net:4024	Copy exactly
Find Process	Look for w3wp.exe	Main process
Add Break Points	Do this before connecting	Makes debugging easier

Application Insights Setup

Application Insights shows you what's happening in your function:

What It Does	What You See	Why It Matters
Watches Live	Current stats	Spot issues now
Catches Errors	Where things broke	Fix problems fast
Shows Usage	Who does what	Plan better
Checks Speed	How fast it runs	Find slow spots

Working With Snapshots

Here's a basic .NET function with logging:

[FunctionName("MyFunction")]
public static async Task<HttpResponseMessage> Run(
    [HttpTrigger(AuthorizationLevel.Anonymous, "get")] HttpRequestMessage req, 
    TraceWriter log)
{
    log.Info("Start MyFunction.Run");
    // Your code here
    log.Info("Function completed");
}

Live Metrics Watch

Keep an eye on these numbers:

Watch This	It Shows You
CPU	How hard it's working
Memory	Space used
Requests	How busy it is
Errors	What's breaking

VS Code Setup

Change This	To This
Debug Port	4024
Config Mode	Debug
Auth Level	Function
Worker Runtime	Your language

Kudu Console Access

Find Kudu at: https://your-function-app.scm.azurewebsites.net

Tool	What It's For
Process Explorer	See what's running
Log Stream	Watch logs happen
Debug Console	Run commands

Cloud Explorer

Do This	How
Pick Resource	Click function app
Turn On Debug	Enable remote
Set Up Ports	Open what's needed
Lock It Down	Add security rules

Note: After March 31, 2025, you'll need to switch from instrumentation keys to connection strings for Application Insights in Azure Functions.

Debug Tips and Rules

Area	What to Watch	What to Do
CPU Load	Max 70% usage	Stop debug if higher
Memory	Keep under 80%	Clear unused objects
Response Time	Max 5 second delay	Remove heavy operations
Active Sessions	Max 3 debug sessions	Close unused ones

Here's what you need to know about debugging: It's NOT just about finding bugs. It's about doing it without breaking your app.

Speed and Performance

Want fast debugging? Here's what slows you down:

Action	Impact on Speed	How to Fix
Setting Breakpoints	+2-3s per point	Set only needed points
Memory Dumps	+5-10s per dump	Use sampling instead
Live Metrics	+1-2s latency	Turn off when not needed
Debug Logging	+3-4s per request	Use filtered logging

Speed things up by:

• Using connection pools for DB work
• Caching frequent lookups
• Adding async/await where it matters
• Being picky about what you log

Security Risks

Here's what can go wrong (and how to fix it):

Risk Type	What Can Happen	How to Stop It
Open Ports	Port 4024 attacks	Close after debug
Debug Data	Memory leaks	Clear after sessions
Auth Tokens	Token theft	Use short-lived keys
Log Files	Data exposure	Clean up after debug

Keep it locked down:

• Kill remote debug when done
• Store secrets in Azure Key Vault
• Lock down debug ports
• Keep sessions short

Debug Mode Limits

Know your boundaries:

Can Do	Cannot Do
Set break points	Change running code
Watch variables	Edit in production
Check memory use	Add new functions
Track requests	Modify app settings

The rules are simple:

• 30 minutes max
• One session per dev
• No prod data
• Test first

"To debug via a publish profile, you can either use the publish profile from Visual Studio or download it from the Azure Portal."

sbb-itb-29cd4f6

Fixing Common Problems

Here's what you need to know about fixing Azure Functions debugging issues.

Connection Issues

Can't connect? Check these common problems:

Issue	Check This	Fix This
Port Blocked	VS 2022: 4026 VS 2019: 4024 VS 2017: 4022	Open needed port in firewall
Wrong URL Format	myfunctionapp.azurewebsites.net:4024	Remove 'https://' prefix
Basic Auth Off	App Service settings	Enable basic auth
Wrong Process	W3WP.exe selection	Switch to Managed CLR for .NET Core

Login Problems

Here's what to do when you can't log in:

Problem	Solution	Extra Steps
Auth Prompt Loop	Enable basic auth in App Service	Restart VS after change
Wrong Credentials	Use Deployment Center creds	Check Azure Portal for latest
NTLM Issues	Set "Network Security: LAN Manager Auth Level"	Use "Send NTLMV2 response only"
Token Expired	Get new deployment profile	Download fresh from Azure Portal

Debugger Attachment Errors

Mac VS Code needs special attention. Here's what to do:

Error Type	Fix Steps	When to Apply
Code Signing	Run codesign commands for vsdbg	After VS Code updates
Runtime Mismatch	Update Azure Function tools	Before debug sessions
Missing Files	Copy runtimes folder to bin	Post-build event

For Mac VS Code, run this:

cd ~/.vscode/extensions/ms-dotnettools.csharp-1.25.2-darwin-x64/.debugger/x86_64
codesign --remove-signature vsdbg-ui && codesign --remove-signature vsdbg
codesign -s my-codesign-cert vsdbg-ui && codesign -s my-codesign-cert vsdbg

Before You Start Debugging:

• Deploy in debug mode
• Match your local and Azure DLL versions
• Set a breakpoint
• Turn on remote debugging in Function App settings

Got missing files locally? Add this post-build event:

XCOPY "$(TargetDir)runtimes" "$(TargetDir)bin/runtimes" /S /E /Y /I /R /D

Setup Guidelines

Here's what you need to get started with your development environment:

Environment Setup

Environment Type	Required Tools	Setup Steps
Local Dev	VS Code, Azure Functions Core Tools, Azurite	1. Install tools 2. Set up local.settings.json 3. Configure Azurite connection
VS 2022	Azure Development Workload	1. Enable Azure workload 2. Install Azure Functions tools 3. Set debug configuration
Command Line	Azure Functions Core Tools, Maven (Java)	1. Install Core Tools 2. Set up runtime 3. Configure templates

Here's your basic local.settings.json configuration:

{
    "IsEncrypted": false,
    "Values": {
        "FUNCTIONS_WORKER_RUNTIME": "dotnet",
        "AzureWebJobsStorage": "UseDevelopmentStorage=true"
    },
    "Host": {
        "LocalHttpPort": 7071,
        "CORS": "*"
    }
}

Production Safety Steps

Let's keep your production environment secure:

Safety Measure	Implementation	Duration
Debug Mode Timeout	Auto-disabled	48 hours
Process Monitoring	Auto-shutdown	After few minutes of inactivity
Debug Access	Basic auth required	Session-based
Port Access	Limited to debug ports	During debug session

Follow these key rules:

• Turn on debug mode ONLY when needed
• Keep secrets in Key Vault
• Move connection strings to app settings
• Set up managed identities for Azure resources

Log Setup

Log Type	Purpose	Setup Location
Host Logs	Runtime issues	host.json
App Logs	Code execution	function.json
Debug Logs	Debug sessions	VS Code/VS settings

Drop this into your host.json:

{
    "logging": {
        "logLevel": {
            "default": "Information",
            "Host.Results": "Error",
            "Function": "Error",
            "Host.Aggregator": "Information"
        }
    }
}

For VS Code, add these debug settings:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Attach to .NET Functions",
            "type": "coreclr",
            "request": "attach",
            "processId": "${command:azureFunctions.pickProcess}"
        }
    ]
}

Next Steps

Here's how to pick and set up the right debugging tools for your Azure Functions:

Debug Method	Best For	Setup Time
VS Debugger	Local development, step-by-step code inspection	5-10 minutes
App Insights	Production monitoring, performance tracking	15-20 minutes
Live Metrics	Real-time monitoring, quick issue detection	10-15 minutes
Kudu Console	Log inspection, file system access	2-5 minutes

Your choice depends on what you're trying to fix, where your code runs, and how much time you have. For example: VS Debugger works best for local code issues, while App Insights helps track live performance problems.

Here's your setup checklist:

1. Get Visual Studio Ready

Your debug setup starts in Visual Studio. Connect it to Azure:

• Add debug settings to your publish profile
• Turn on remote debugging in Azure
• Link Application Insights

2. Lock Down Security

Keep your debug environment safe:

• Get your publish profile for auth
• Open debug port 4024
• Set up Basic Auth

3. Set Up Monitoring

Track everything that matters:

• Turn on Application Insights
• Create alerts for key metrics
• Add custom tracking

Here's what to watch during debugging:

Resource Type	Management Action	Update Frequency
Memory	Set function timeout	Every debug session
CPU	Monitor process usage	Real-time
Storage	Check connection string	Start of session
Network	Track dependencies	Continuous

Watch out for these limits:

• Debug sessions stop after 48 hours
• Process monitoring ends when inactive
• Debug ports only work during active sessions
• Debug mode uses more memory

Quick tip: Want to see how your function performs? Check Application Insights Analytics - it shows you everything from dependency chains to performance stats during debug runs.

FAQs

Question	Answer	Setup Time
What is remote debugging in Azure?	A tool that links Visual Studio debugger to your App Service. Access it through Azure Portal > App Services > Your App.	5-10 minutes
How to debug the Azure function?	1. Open Azure Portal > Function App > Configuration 2. Go to General Settings > Debugging 3. Turn on Remote Debugging and select your VS version	10-15 minutes
How to debug an Azure function in production?	1. In Visual Studio, click Debug > Attach to Process 2. Enter Connection target: [function-url]:4024 3. Pick w3wp.exe process	15-20 minutes

Here's what you need to check in your debug settings:

Setting	Where to Find It	What It Does
Remote Debug Port	Azure Portal > Configuration	Sets port to 4024
Visual Studio Version	General Settings	Matches your VS version
Process Name	Attach Window	Finds w3wp.exe
Debug Mode	Configuration	Turns debugging on/off

Before you start debugging:

• Switch off "Require source files to exactly match original version" in VS
• Turn off "Enable Just My Code"
• Open port 4024 in your firewall
• Get the correct publish profile

Here's how long you can debug:

Environment	Time Limit	What to Know
Development	No limit	Works on local machine
Test/Staging	48 hours	Stops after time's up
Production	1 hour	Quick fixes only

Important: You'll need to turn on remote debugging in Configuration - it starts in the OFF position.

Related posts

• .NET Security Updates: Releases, Patches, Best Practices
• WCF Performance Monitoring: Top Tools & Counters
• Azure Key Vault Logging: 7 Best Practices
• CI/CD Rollback Strategies: 7 Best Practices