Web Tools Collection | hidekazu-konishi.com

Welcome to my collection of web tools!
Here you'll find various utilities, converters, generators, and productivity tools I've developed to solve common problems and streamline everyday tasks. All tools are free to use and work directly in your browser without installations or downloads.
Each tool is designed with simplicity and functionality in mind, focusing on providing immediate value for specific use cases. Whether you're a developer, content creator, or simply someone looking for handy utilities, you'll find these tools helpful for your specific needs.

Disclaimer: These tools are provided "as is" without warranties. Use at your own risk. Results may utilize third-party services and should be verified independently. By using these tools, you accept full responsibility for any outcomes. For more details, please refer to our Web Tools Disclaimer.

Available Web Tools

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Last Updated:

  1. SSL/TLS Certificate Decoder and Chain Inspector - X.509 PEM/DER Viewer
  2. DKIM / SPF / DMARC Record Builder and Validator - Email Authentication DNS TXT Record Generator
  3. Email Header Analyzer Tool - Received Chain, SPF/DKIM/DMARC, and Authentication-Results Inspector
  4. HTTP Security Header Analyzer Tool - CSP HSTS X-Frame-Options Audit with Grade and Recommendations
  5. Image Format Converter Tool - Client-Side HEIC WebP AVIF JPG PNG GIF BMP Batch Converter
  6. Markdown Table Visual Editor Tool - Spreadsheet-style GFM Table Builder with CSV/TSV/JSON Import
  7. JSONPath / JMESPath Query Tester Tool - Real-Time JSON Query Evaluator for AWS CLI --query
  8. API Request / curl Command Builder - Multi-Language HTTP Code Generator (curl, fetch, axios, requests, Go)
  9. Mermaid Diagram Live Editor Tool - Real-time Flowchart, Sequence, ER, and AWS Architecture Diagram Editor with SVG and PNG Export
  10. CSV Preview and Statistics Tool - In-Browser CSV Profiler with Type Inference and Histograms
  11. S3 Bucket Policy Generator Tool - Visual Builder and Linter for AWS S3 Bucket Policies
  12. PDF Text Extractor and Search Tool - Extract Text from PDF with Page Range and In-Browser Search
  13. SVG Optimizer Tool - Free Online SVG Cleaner and Minifier
  14. Character Encoding Converter Tool - Japanese Encoding Conversion and Mojibake Repair
  15. Line Ending / BOM Converter Tool - Free Online CRLF LF CR Newline and UTF-8 BOM Converter
  16. Password Strength Checker Tool - Entropy, Crack Time, and zxcvbn-based Password Diagnostic
  17. GraphQL Query Builder and Formatter Tool - SDL-Driven Query Generator and Validator
  18. WebAuthn / Passkey Test Tool - Browser-Side Registration and Authentication Inspector
  19. Athena Partition Projection Calculator - Partition Count and Path Preview Tool
  20. OpenAPI API Gateway Import Linter Tool - Validate OpenAPI Definitions for AWS API Gateway REST and HTTP APIs
  21. CodeBuild buildspec.yml Validator - Static Checker for Phases, Env, Artifacts and Reports
  22. AWS CLI Command Generator - Build AWS CLI Commands from GUI Form
  23. VTL Template Tester - Offline Velocity Template Language Evaluator for API Gateway and AppSync
  24. CloudTrail Event Viewer - Highlight, Filter, and Search AWS CloudTrail Events
  25. AWS Policy Diff Tool - Statement-Level IAM / S3 Bucket / KMS Key Policy Comparison
  26. S3 Lifecycle Policy Builder Tool - Generate JSON / XML / CloudFormation for S3 Rules
  27. EventBridge cron/rate Expression Validator - AWS Schedule Tester with Next Run Times
  28. S3 Storage Class Cost Comparison Tool - Compare Amazon S3 Storage Class Costs Across Access Patterns and Retention
  29. CloudWatch Logs Insights Query Builder - Visual Logs Insights Query Composer with Syntax Check
  30. CloudWatch Metric Filter Pattern Tester - Preview Matches and Extracted Values for Log Events
  31. Lambda Cost Estimator Tool - Monthly Cost Calculator with Tiered Pricing and Free Tier
  32. DynamoDB Capacity Calculator Tool - RCU/WCU and Monthly Cost Estimator
  33. Security Group Rule Overlap Detector - AWS SG Audit Tool
  34. VPC CIDR Subnet Planner - Multi-AZ Subnet Designer with CloudFormation/Terraform Output
  35. CloudFormation YAML JSON Converter Tool - Bidirectional Converter with Short-form Intrinsic Functions
  36. ARN Parser Builder Tool - AWS ARN Parser, Builder, and Batch Analyzer
  37. SAM Template Transform Preview - AWS::Serverless Transform Expander
  38. Step Functions ASL Validator and Visualizer - AWS State Machine Syntax Checker and Flow Diagram
  39. EventBridge Pattern Tester - Test Event Patterns Against Multiple Sample Events
  40. IAM Policy Least Privilege Analyzer - Detect Overly Permissive IAM Policies Offline
  41. IAM Policy Simulator (Offline) - Client-Side AWS IAM Policy Evaluator
  42. CFN Intrinsic Function Resolver - Resolve CloudFormation Intrinsic Functions Locally
  43. CloudFormation Template Linter Tool - Client-Side cfn-lint Subset for YAML and JSON Templates
  44. Typing Speed Test and Practice Tool - WPM Test, Code Typing with Keystroke Heatmap
  45. Image to PDF Converter Tool - Convert Multiple Images to PDF with Smart Layout
  46. Barcode Generator Tool - Multi-Format 1D Barcode Creator with Batch Generation
  47. Image Watermark Tool - Add Text and Logo Watermarks to Photos with Batch Processing
  48. Digital Signature Pad Tool - Handwriting Signature Creator with PDF Signing
  49. Chart Graph Maker Tool - Interactive Data Visualization and Chart Creator
  50. Code Screenshot Generator Tool - Beautiful Code to Image Converter with Syntax Highlighting
  51. OG Image Generator Tool - Open Graph and Social Card Image Creator
  52. JSON to Type Generator Tool - Multi-Language Type Definition Generator with Smart Inference
  53. JSON Schema Generator Validator Tool - Multi-Sample Schema Inference with Format Detection
  54. JSON Diff Tool - Structural JSON Compare with JSONPath and RFC 6902 Patch
  55. Markdown Live Editor Tool - Real-time GFM Editor with Live Preview and Syntax Highlighting
  56. Schema.org JSON-LD Generator Tool - Structured Data Markup Generator with Google Rich Results Preview
  57. Color Palette Generator Tool - Harmony-Based Palette Creator with Image Extraction and Contrast Matrix
  58. PDF to Image Converter Tool - Convert PDF Pages to PNG JPEG WebP with DPI Control
  59. IP Subnet Calculator Tool - CIDR VLSM IPv4 IPv6 Network Calculator
  60. XML Formatter Validator Tool - Online XML Beautifier with XPath Tester and Tree Viewer
  61. PDF Merge Split Tool - Combine Split and Extract PDF Pages Online
  62. Image EXIF Metadata Viewer and Remover Tool - Privacy-Focused Photo Metadata Analyzer with GPS Map and Lossless Stripping
  63. Image Compressor Tool - Client-Side Image Compression Resizing and Format Conversion
  64. Favicon App Icon Generator Tool - Complete Favicon Package with ICO PNG and PWA Icons
  65. CSS Gradient Generator Tool - Linear Radial and Conic Gradient Maker with Multi-Layer Support
  66. Meta Tag OGP Generator Tool - Open Graph Twitter Card and Meta Tag Generator with Live Preview
  67. Number Base Converter Tool - Binary Decimal Hex Octal Converter with Bit Visualization
  68. CSV JSON Converter Tool - CSV to JSON and JSON to CSV Online Converter
  69. Lorem Ipsum Generator Tool - Multi-Style Dummy Text and Placeholder Content Generator
  70. HTML Entity Encoder Decoder Tool - Encode Decode and Reference HTML Special Characters
  71. SQL Formatter Tool - Online SQL Beautifier Minifier and Syntax Highlighter
  72. Chmod Permission Calculator Tool - Unix File Permission Calculator with Umask Support
  73. Word Character Counter Tool - Free Online Text Analyzer with Reading Time and Keyword Density
  74. URL Encoder Decoder Tool - Multi-Mode URL Encoding and Decoding with URL Parser
  75. Color Converter and WCAG Contrast Checker Tool - HEX RGB HSL Converter with Accessibility Testing
  76. Cron Expression Parser and Builder Tool - Schedule Generator with Next Run Times
  77. Diff Text Compare Tool - Free Online Side-by-Side Text Difference Checker
  78. Regex Tester Tool - Online Regular Expression Tester and Explainer
  79. JWT Encoder Tool - JSON Web Token Generator and Signer
  80. JWT Decoder Tool - JSON Web Token Inspector and Debugger
  81. YAML JSON Converter Tool - Bidirectional YAML and JSON Online Converter
  82. QR Code Generator and Reader Tool - Create and Scan QR Codes Online
  83. UUID ULID Generator Tool - Generate and Decode UUID v4, v7 and ULID
  84. JSON Formatter Validator Tool - Online JSON Beautifier Minifier and Tree Viewer
  85. Text Case Converter Tool - Free Online Text Transformation and Case Changer
  86. Unix Timestamp Converter Tool - Epoch Time and Date Converter with Timezone Support
  87. Base64 Encoder Decoder Tool - Text and File Base64 Encoding with Data URI Support
  88. Password Generator Tool - Secure Random Password and Passphrase Generator with Strength Checker
  89. Hash Generator Tool - Multi-Algorithm Hash Calculator with File Support
  90. Markdown HTML Converter Tool - Client-Side Parser and Free Online Converter
  91. JavaScript CSS Minifier Tool - Free Online Code Minification and Compression
  92. IP Range to CIDR Converter Tool - Free Online Network Calculator
  93. AES Encryption Decryption Tool - Client-Side Crypto Cipher and Free Online Encryptor Decryptor
  94. Free Website Speed Test Tool - Lighthouse and PageSpeed Insights Analysis

References:
Tech Blog with curated related content

Written by Hidekazu Konishi