Day 1 -Simple Website & API Debugging Guide

Simple Website & API Debugging Guide

Professional Developer Troubleshooting Guide

Simple Website & API
Debugging Guide

Learn how professional developers identify, troubleshoot, and fix website, database, API, and frontend issues using modern debugging techniques. This complete guide helps beginners and developers solve problems faster.

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Understand The Problem

Before fixing anything, first understand exactly what is failing. Never guess the issue.

What is not working?
What error is showing?
When does the issue happen?
Can the issue be reproduced?

Examples:• Login not working • API not saving data • Button not responding • Page showing server error

Run The Project

Open the project in Visual Studio and start the application in Debug Mode.

Press F5

This allows breakpoints and debugging tools to work properly.

Add Breakpoint

Breakpoints stop the code execution at a specific line. This helps inspect variables and application flow.

Open Controller File
Click near line number
Red dot appears

public IActionResult SaveData() { // Add Breakpoint Here }

Check API Hit

Now call the API from different tools and verify whether the request reaches the backend.

Website
Swagger
Postman

If Breakpoint Stops: ✓ API is hitting correctlyIf Breakpoint Does Not Stop: ✗ Wrong Route ✗ Wrong URL ✗ Wrong HTTP Method ✗ Token Issue

Check Variable Values

Move step-by-step through the code using debugger controls.

Press F10

Check if value is null
Check if value is empty
Verify correct data

Check SQL Query

Before query execution, verify the database query and parameters carefully.

Query syntax is correct
Parameters contain values
Database connection is open

Test Query Directly In:• SQL Server • MySQL Workbench

Professional Debugging Process

Do not randomly change code. Always follow a structured debugging process: Add breakpoint → Check values → Identify failing line → Fix carefully → Test again.

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Day 2 - API Testing & Error Handling

Professional Backend Development Training

API Testing
& Error Handling

Master professional API debugging, authentication testing, error handling, request validation, response analysis, logging systems, and backend troubleshooting techniques used by modern software engineers.

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Understand The API

Always understand the request before testing APIs professionally.

API URL
Request Type
Headers
Authorization Token
Request Body

Test Using Swagger & Postman

Use modern API testing tools to verify requests correctly.

✓ Correct URL ✓ Correct HTTP Method ✓ Correct Request Body ✓ Correct Headers

Verify Request Body

Validate JSON structure carefully before sending requests.

{ "driverId":"101", "remarks":"Lost Mobile" }

Wrong Property Names
Missing Values
Invalid JSON Format

Check API Response

Verify response codes and backend messages carefully.

{ "success": true, "message": "Data Saved Successfully" }

Error Handling

Professional applications always capture exceptions properly.

try { // Save Data } catch(Exception ex) { return BadRequest(ex.Message); }

Authentication Validation

Verify API token authentication before testing secured APIs.

Authorization: Bearer your_token_here

Validate Database Records

Never assume data is saved successfully without database verification.

Verify Inserted Data
Check Null Values
Validate SQL Execution

Understand Status Codes

Code	Description
200	Success
201	Created Successfully
400	Bad Request
401	Unauthorized
500	Server Error

Add Logs

Logging helps identify the exact execution point of failures.

Console.WriteLine("API Started"); Console.WriteLine("Data Inserted");

Professional API Flow

API Request Sent?
↓
API Hit?
↓
Request Body Correct?
↓
Token Valid?
↓
SQL Executed?
↓
Database Updated?
↓
Response Returned?

Professional API Testing Workflow

Modern developers never debug randomly. Professional API testing follows a structured flow: Validate request → Check authentication → Debug backend → Verify database → Handle errors → Return proper responses.

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Day 3 - Database & SQL Troubleshooting

Day 3 — SQL Debugging & Database Validation

Database & SQL
Troubleshooting

Learn professional SQL debugging techniques, database validation methods, query troubleshooting, parameter checking, and production-safe debugging workflows.

Understand The Issue

Always identify the exact database problem before making changes.

Data not inserting
Data not updating
Wrong records showing
SQL timeout
Connection issue

Check Connection

Verify database connectivity and validate connection credentials.

connection.Open();

Server name
Database name
Username & password
Connection string

Verify SQL Query

Ensure the SQL query syntax and conditions are correct.

SELECT * FROM employees
WHERE employee_id = @employeeId

Correct table name
Correct columns
Valid WHERE condition
No syntax errors

Test Query Directly

Run SQL manually inside database tools to isolate the issue.

SQL Server Management Studio
MySQL Workbench
pgAdmin
Oracle SQL Developer

Validate Parameters

cmd.Parameters.AddWithValue(
"@employeeId",
employeeId
);

Null values
Wrong datatype
Empty strings
Missing parameter

Check Rows Affected

int rows = cmd.ExecuteNonQuery();

Condition failed
No matching records
Insert/update issue
Transaction rollback

Handle Exceptions

try
{
   connection.Open();
}
catch(Exception ex)
{
   string error = ex.Message;
}

SQL exceptions usually reveal the exact problem immediately.

Verify Saved Data

Refresh table
Check saved values
Verify null columns
Check duplicates

Common SQL Issues

Timeout errors
Null value errors
Connection failures
Wrong WHERE condition
Long running queries

Professional SQL Debugging Flow

Database Connected?

→

SQL Query Correct?

→

Parameters Correct?

→

Query Executed?

→

Rows Affected?

→

Data Saved?

Professional Debugging Tips

Use Parameterized Queries

Prevent SQL Injection attacks and improve database security.

Enable Logging

Log SQL queries, execution time, parameters, and error messages.

Never Debug in Production

Always test queries in development or staging environments first.

Optimize Query Performance

Use indexes and avoid unnecessary SELECT * queries.

Day 4 - Frontend & UI Debugging Guide

Frontend & UI Debugging Guide

Professional Frontend Troubleshooting Workflow

Frontend & UI
Debugging Guide

Master modern website frontend debugging techniques including UI troubleshooting, JavaScript debugging, CSS fixing, API verification, browser inspection, and professional issue tracking workflow.

Professional Debugging Steps

Advanced frontend troubleshooting process used by professional developers.

Understand the Issue

Identify and reproduce the UI issue clearly before starting debugging.

Button not working
CSS broken
JavaScript error
Data not displaying

Open Developer Tools

Use browser inspection tools to analyze frontend behavior.

Press F12

Console
Network
Elements
Sources

Check Console Errors

Analyze JavaScript console errors carefully.

Uncaught TypeError
Cannot read property 'value' of null

Verify API Calls

Inspect failed requests inside the network tab.

API URL
Status Code
Payload
Response Data

Check HTML Elements

Verify element IDs and classes properly exist.

document.getElementById("username")

Verify CSS Issues

Inspect layout, responsive design, and stylesheet loading.

CSS file loaded
Styles overridden
Responsive issue
Flex/Grid alignment

Check JS Functions

Verify click events and JavaScript execution flow.

function saveData() { console.log("Button Clicked"); }

Use Console Logs

Track execution using professional console logging.

console.log("Step 1"); console.log(response);

Common Frontend Issues

404 Error → Wrong API URL
500 Error → Backend issue
CSS Missing → Wrong file path
Button Failure → JavaScript issue

Frontend Debugging Flow

Page Loaded?
↓
CSS Loaded?
↓
JavaScript Loaded?
↓
Button Clicked?
↓
API Called?
↓
Response Received?
↓
Data Displayed?

Day 5 - Authentication & Token Debugging

Authentication & JWT Debugging Guide

🔐 Authentication & JWT Security

Modern Authentication & Token Debugging Guide

Master JWT authentication debugging, authorization troubleshooting, login API testing, secure token validation, frontend token storage, and backend security workflows with this ultra-modern professional developer guide.

Start Learning Read FAQ

Authentication Checklist

✅ Login API

Verify login API returns valid JWT token successfully.

✅ Authorization

Ensure Bearer token is sent correctly in request headers.

✅ Token Storage

Verify frontend stores JWT token securely before API calls.

✅ User Claims

Check roles, permissions, and authenticated user information.

Authentication Debugging Workflow

Professional step-by-step debugging process for JWT authentication, API authorization, login systems, and secure token validation.

Understand the Issue

Identify the exact authentication problem before debugging.

User unable to login
401 Unauthorized
403 Forbidden
Token expired
Session issue

Verify Login API

Test authentication APIs using Swagger, Postman, or frontend forms.

POST /api/login

Check JWT Token

Verify JWT token generation after successful login response.

{
 "token":"eyJhbGciOiJIUzI1NiIs..."
}

Authorization Header

Protected APIs require proper Bearer token authorization headers.

Authorization: Bearer your_token

Check Token Expiry

Expired tokens are common reasons for authorization failures.

401 Unauthorized
Token expired
Invalid signature

Backend Authorization

Add breakpoints inside protected APIs and authentication middleware.

[Authorize]
public IActionResult GetData()
{
   // Breakpoint here
}

Professional Authentication Flow

Token Generated?

Token Stored?

Authorization Sent?

Token Valid?

API Authorized?

Response Returned?

Common Authentication Issues

Professional troubleshooting table for JWT authentication and authorization errors.

Error	Cause	Solution
401 Unauthorized	Expired or invalid JWT token	Generate new token and verify authorization header
403 Forbidden	User lacks required permissions	Verify user roles and policies
Login Failed	Wrong username or password	Check credentials and password hashing
Token Missing	Authorization header not sent	Send Bearer token correctly
Invalid Signature	JWT secret mismatch	Verify JWT secret configuration

Frequently Asked Questions

Quick answers about JWT authentication debugging and API authorization troubleshooting.

Why do I get 401 Unauthorized?

Usually caused by expired tokens, invalid JWT signatures, or missing authorization headers.

What causes 403 Forbidden?

403 errors occur when authenticated users lack required permissions or roles.

Where should JWT tokens be stored?

JWT tokens are commonly stored in localStorage, sessionStorage, or secure HTTP-only cookies.

Build Secure Authentication Systems

Use professional authentication debugging workflows to create secure, scalable, and reliable modern web applications.

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Day 6 - Performance & Timeout Troubleshooting

Day 6 – Performance & Timeout Troubleshooting

Professional guide for identifying, analyzing, and optimizing slow websites, APIs, SQL queries, frontend resources, and server performance issues.

Introduction

Website performance directly affects user experience, SEO rankings, conversion rates, and application reliability.

Slow-loading pages, delayed APIs, SQL timeouts, and server freezing are common issues in modern web applications.

This guide explains how to professionally troubleshoot and optimize website speed and timeout problems step-by-step.

Step 1 — Identify the Performance Issue

Before fixing any issue, identify the exact source of the slowdown.

Common Performance Problems

Website loading slowly
API response delay
SQL query timeout
Page freezing or hanging
Slow dashboard loading
Delayed server response

Professional Tip: Determine whether the issue originates from the frontend, backend, database, or server infrastructure.

Step 2 — Check API Response Time

Browser Developer Tools help analyze API performance and request behavior.

F12 → Network Tab

Verify the Following

API response time
Request payload size
Failed requests
HTTP status codes
Repeated API calls

Issue	Impact
Large payloads	Slow loading speed
Multiple requests	Increased latency
Failed requests	Application instability
Slow endpoints	Backend or database delay

Step 3 — Identify SQL Timeout Issues

Database queries are one of the biggest causes of application slowdowns.

SELECT * FROM orders
WHERE status = 'Pending'

Common Reasons for SQL Timeout

Large database tables
Missing indexes
Complex joins
Unoptimized queries
Returning unnecessary data

Step 4 — Optimize SQL Queries

Optimized queries reduce execution time and improve overall application performance.

Best Practices

Select only required columns
Use proper indexes
Avoid unnecessary loops
Reduce nested queries
Use optimized WHERE conditions

SELECT id, name
FROM employees
WHERE employee_id = @employeeId

Optimization Benefit: Faster query execution, lower memory usage, and improved API response times.

Step 5 — Check Backend Processing

Backend business logic can also cause major performance bottlenecks.

Console.WriteLine("API Started");
Console.WriteLine("SQL Executed");
Console.WriteLine("Response Returned");

Common Backend Problems

Heavy calculations
Infinite loops
Multiple database calls
Blocking operations
Third-party API delays

Step 6 — Reduce Large Data Loading

Loading unnecessary data can slow both frontend and backend systems.

Recommended Techniques

Pagination
Batch processing
Lazy loading
Limit returned records

SELECT TOP 50 * FROM customers

Large datasets increase memory usage, rendering time, and network transfer delays.

Step 7 — Optimize Frontend Performance

Frontend optimization improves user experience and page speed.

Common Frontend Issues

Large image files
Too many JavaScript files
Unused CSS
Heavy third-party libraries
Excessive API requests

Optimization Techniques

Lazy loading
Minified CSS & JS
Image compression
Browser caching
CDN implementation

Step 8 — Monitor Server Resources

Server health plays a major role in website performance.

Resource	Importance
CPU Usage	High CPU slows processing
Memory Usage	Low memory causes freezing
Disk Space	Storage issues affect speed
Network Usage	Bandwidth impacts response time

Monitoring Tools

Task Manager
Performance Monitor
Azure Monitor
AWS CloudWatch
Grafana
Prometheus

Step 9 — Common Performance Problems

SQL Timeout

Usually caused by slow or unoptimized database queries.

Slow API

Heavy backend processing or repeated database calls can delay responses.

Slow Website

Large frontend resources and unoptimized assets impact loading speed.

Server Freeze

High CPU or memory usage can cause application instability.

Step 10 — Professional Performance Debugging Flow

Website Slow?
↓
Frontend Slow?
↓
API Slow?
↓
SQL Slow?
↓
Server Overloaded?
↓
Performance Optimized?
↓
Response Improved?

This structured troubleshooting approach helps identify the exact bottleneck quickly and efficiently.

Best Practices for Performance Optimization

Optimize SQL queries regularly
Use caching wherever possible
Compress frontend assets
Reduce API payload size
Monitor server resources continuously
Implement lazy loading
Use asynchronous processing
Enable browser caching

Conclusion

Performance troubleshooting is an essential skill for modern web developers and system engineers.

By analyzing frontend resources, APIs, SQL queries, backend processing, and server infrastructure, developers can quickly identify bottlenecks and improve application speed and reliability.

Proper optimization leads to:

Faster response times
Improved scalability
Better user experience
Reduced server load
Higher application stability

Day 6 Summary

Identifying performance bottlenecks
Checking API response times
Troubleshooting SQL timeout issues
Optimizing database queries
Improving backend performance
Optimizing frontend assets
Monitoring server resources
Following a professional debugging workflow

Day 7 - Production & Live Server Troubleshooting

Day 7 • Production & Live Server Troubleshooting

Professional Live Website Debugging & Deployment Guide

Master enterprise-level production troubleshooting, deployment debugging, API diagnostics, server monitoring, IIS verification, database validation, and real-world live website issue resolution techniques.

Explore Guide Troubleshooting Flow

Production Troubleshooting Steps

A complete enterprise-level production debugging workflow for modern web applications.

Understand the Production Issue

Identify the exact issue before making any changes in production.

Website not loading
API failing in production
Database errors
Slow server performance
User-reported issues

Never directly modify production code without proper verification.

Verify Server Status

Ensure all required services are actively running.

IIS running
Application pool active
API service started
Server reachable

IIS → Application Pools → Start

Check Production Logs

Logs reveal the actual failing area in production systems.

Application logs
Error logs
Server logs
Windows Event Viewer

logs/error-log.txt

Verify Database Connection

Ensure production database connectivity is working properly.

Correct server
Correct database
Valid credentials
Firewall access

appsettings.Production.json

Check Production APIs

Test APIs directly using professional API testing tools.

Swagger
Postman
Browser testing
Status code validation

https://yourdomain.com/api/test

Verify Deployment Files

Ensure deployment completed successfully without missing files.

DLL files copied
Environment updated
Config verified
Latest build deployed

publish/
web.config
appsettings.json

Verify Permissions

Production permission issues are extremely common.

Database permissions
Folder access
API authorization
Server privileges

Permission problems often appear only in production.

Monitor Server Health

Monitor live server performance continuously.

CPU usage
Memory consumption
Disk space
Network traffic

Monitoring prevents downtime and improves stability.

Common Production Problems

Frequently encountered live server issues.

500 Internal Server Error
503 Service Unavailable
Database connection failed
Deployment failure

Professional Troubleshooting Flow

Follow this enterprise-level debugging sequence for fast issue resolution.

Server Running?

↓

Application Started?

↓

Database Connected?

↓

API Working?

↓

Logs Checked?

↓

Permissions Correct?

↓

Issue Resolved?

Production Best Practices

Professional standards for maintaining secure and stable production systems.

Backup Everything

Always maintain backups before deployments or production changes.

Use Staging Environment

Test deployments before publishing to live production servers.

Enable Logging

Detailed logging helps identify failures quickly and accurately.

Continuous Monitoring

Monitor uptime, API performance, memory usage, and server resources.

Day 8 - Logging & Error Monitoring

⚡ Day 8 • Logging & Error Monitoring

Professional Error Tracking
& Application Monitoring

Master enterprise-level logging systems, API monitoring, exception handling, database tracking, performance analysis, and real-world production debugging techniques used in modern ASP.NET Core applications.

Explore Documentation View Monitoring Flow

API Monitoring

Track incoming requests, responses, execution flow, and failed endpoints.

Error Tracking

Identify exceptions, stack traces, and production failures instantly.

Performance Analysis

Monitor API response times, database performance, and bottlenecks.

Professional Logging Workflow

Enterprise-level monitoring and debugging techniques for modern applications.

Why Logging Matters

Logging helps developers identify issues quickly during development and production.

Track application flow
Identify runtime errors
Monitor API execution
Analyze production failures

Good logging significantly reduces debugging time.

Simple Console Logs

Use console logging to verify execution flow step-by-step.

Console.WriteLine("API Started");
Console.WriteLine("Data Saved");
Console.WriteLine("Response Returned");

Use ILogger

ASP.NET Core provides a built-in enterprise logging framework.

private readonly ILogger _logger;

_logger.LogInformation("API Executed");
_logger.LogError("Error Occurred");

Track execution flow
Capture application events
Log critical exceptions

Log Exceptions Properly

Always capture exceptions using try-catch blocks.

try
{
    // Code
}
catch(Exception ex)
{
    _logger.LogError(ex.Message);
}

Error message
Stack trace
Inner exception

Monitor API Requests

Track incoming API requests and outgoing responses.

Request Started
Request Completed
Status Code: 200
Slow API detection

Monitor Database Errors

Log SQL failures and database connectivity issues professionally.

Database connection failed
SQL timeout
Invalid query
Connection issue

Never expose sensitive database details in public logs.

Production Log Verification

Analyze production logs to identify real-world issues.

Application logs
IIS logs
Error logs
Windows Event Viewer

logs/application-log.txt

Identify Common Errors

Logs help identify and diagnose the most common production issues.

Error	Description
Null Error	Missing object value
SQL Timeout	Slow database query
401 Error	Authentication failed
500 Error	Unhandled exception

Performance Monitoring

Track API response times and database query performance.

API Response Time: 250ms
Database Query Time: 100ms

Performance logs help identify bottlenecks and slow operations.

Professional Logging Flow

Enterprise-level monitoring workflow for issue identification and resolution.

Request Started?

↓

API Executed?

↓

Database Connected?

↓

Error Occurred?

↓

Logs Generated?

↓

Issue Identified?

↓

Issue Fixed?

Monitoring Benefits

Professional logging systems improve application reliability and debugging efficiency.

90%

Faster Issue Detection

24/7

Continuous Monitoring

250ms

API Performance Tracking

100%

Production Visibility

Day 9 - Git & Code Deployment Guide

PROFESSIONAL DEVOPS WORKFLOW

Day 9 — Git & Code Deployment Guide

Master modern version control, team collaboration, source management, and professional deployment workflow using Git and .NET deployment practices.

Understand Version Control

Git helps developers track changes, collaborate efficiently, and deploy applications safely.

Track code history
Restore old versions
Manage team collaboration
Prevent accidental overwrites

Check Git Status

Verify repository state before starting development.

git status

Modified files
Pending commits
Current branch info

Pull Latest Code

Always sync your local repository before starting work.

git pull origin main

Prevents conflicts
Gets latest updates
Protects team changes

Create New Branch

Separate branches keep development organized and safe.

git checkout -b feature/login-fix

Safe feature development
Easy rollback
Professional workflow

Add & Commit Changes

Commit code using meaningful messages.

git add .
git commit -m "Fixed login issue"

Clean project history
Easy debugging
Better collaboration

Push Code

Upload latest commits to remote repository.

git push origin feature/login-fix

Backup code safely
Share with team
Prepare for PR

Create Pull Request

Submit code for team review before deployment.

Improve code quality
Reduce production bugs
Follow coding standards
Enable team collaboration

Deploy Application

Publish optimized production build.

dotnet publish -c Release

Verify build success
Update environment settings
Deploy latest version

Verify Deployment

Validate application after deployment.

Website loading
API testing
Database verification
Log monitoring

Professional Deployment Flow

Pull Latest Code

↓

Create Branch

↓

Develop Feature

↓

Commit Changes

↓

Push Code

↓

Create Pull Request

↓

Deploy Application

↓

Verify Production

Deployment Verification Checklist

Component	Status
Website	Loading Correctly
API	Working Properly
Database	Connected Successfully
Logs	No Critical Errors

Day 10 - Real Project Debugging Workflow

⚡ Professional Debugging & Troubleshooting Workflow

Day 10
Real Project Debugging Workflow

Master modern enterprise-level debugging techniques used by professional developers to identify, analyze, troubleshoot, and resolve real production issues efficiently.

10

Debugging Steps

4

Application Layers

100%

Production Validation

Professional Debugging Process

Structured troubleshooting workflow used in real software projects.

Understand the Issue

Never start fixing code without understanding the actual reported problem.

Who reported the issue?
What exactly failed?
When did it happen?
Can it be reproduced?

Reproduce the Issue

Follow exact user steps to recreate the error consistently.

Open Website
↓
Login
↓
Navigate to Page
↓
Click Action
↓
Observe Error

Identify Failed Layer

Determine which system layer is failing.

Frontend → UI / JavaScript
API → Backend Request
Database → SQL / Data
Server → Hosting Environment

Add Breakpoints & Logs

Track execution flow using logs and debugger breakpoints.

Console.WriteLine("API Started");

[HttpPost]
public IActionResult Save()
{
    // Breakpoint Here
}

Verify API Request

Use Browser Network tab or Postman to validate requests.

200 → Success
400 → Bad Request
401 → Unauthorized
500 → Server Error

Verify Database

Validate SQL queries and database operations carefully.

SELECT * FROM users
WHERE user_id = @userId

Correct data returned
Rows updated properly
No SQL timeout

Analyze Logs & Exceptions

Application logs reveal the actual failure point.

Error: Object reference not set
SQL Timeout Exception
401 Unauthorized

Fix Root Cause

Avoid temporary fixes and solve the actual issue permanently.

Validate all conditions
Handle exceptions properly
Test edge cases
Apply permanent fix

Test Before Deployment

Never deploy untested fixes to production.

Frontend verified
API tested
Database validated
No new issues introduced

Professional Real Project Workflow

Enterprise debugging lifecycle used by software teams.

Issue Reported

↓

Issue Reproduced

↓

Layer Identified

↓

Breakpoints Added

↓

Logs Verified

↓

Root Cause Found

↓

Fix Applied

↓

Testing Completed

↓

Deployment Done

↓

Production Verified

Production Verification

Final validation checklist before completing deployment.

🌐

Frontend

UI loading and functionality verified successfully.

✅ Verified

⚡

API

All endpoints responding correctly without failures.

✅ Verified

🗄️

Database

Database operations executing without timeout issues.

✅ Verified

📋

Logs

No critical exceptions or production failures detected.

✅ Verified

Simple Website & API Debugging Guide

Understand The Problem

Run The Project

Add Breakpoint

Check API Hit

Check Variable Values

Check SQL Query

Professional Debugging Process

API Testing & Error Handling

Understand The API

Test Using Swagger & Postman

Verify Request Body

Check API Response

Error Handling

Authentication Validation

Validate Database Records

Understand Status Codes

Add Logs

Professional API Flow

Professional API Testing Workflow

Database & SQLTroubleshooting

Understand The Issue

Check Connection

Verify SQL Query

Test Query Directly

Validate Parameters

Check Rows Affected

Handle Exceptions

Verify Saved Data

Common SQL Issues

Professional SQL Debugging Flow

Professional Debugging Tips

Use Parameterized Queries

Enable Logging

Never Debug in Production

Optimize Query Performance

Frontend & UI Debugging Guide

Professional Debugging Steps

Understand the Issue

Open Developer Tools

Check Console Errors

Verify API Calls

Check HTML Elements

Verify CSS Issues

Check JS Functions

Use Console Logs

Common Frontend Issues

Frontend Debugging Flow

Modern Authentication & Token Debugging Guide

Authentication Checklist

✅ Login API

✅ Authorization

✅ Token Storage

✅ User Claims

Authentication Debugging Workflow

Understand the Issue

Verify Login API

Check JWT Token

Authorization Header

Check Token Expiry

Backend Authorization

Professional Authentication Flow

Common Authentication Issues

Frequently Asked Questions

Why do I get 401 Unauthorized?

What causes 403 Forbidden?

Where should JWT tokens be stored?

Build Secure Authentication Systems

Introduction

Step 1 — Identify the Performance Issue

Common Performance Problems

Step 2 — Check API Response Time

Verify the Following

Step 3 — Identify SQL Timeout Issues

Common Reasons for SQL Timeout

Step 4 — Optimize SQL Queries

Best Practices

Step 5 — Check Backend Processing

Common Backend Problems

Step 6 — Reduce Large Data Loading

Simple Website & API
Debugging Guide

API Testing
& Error Handling

Database & SQL
Troubleshooting

Frontend & UI
Debugging Guide

Professional Error Tracking
& Application Monitoring