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

First Published:
Last Updated:

  1. Anthropic Tool Use Schema Builder and Validator Tool - Build and Validate Claude Function Calling Definitions
  2. MCP Capability Inspector and Schema Validator Tool - Inspect tools, resources, and prompts and Flag Risky MCP Declarations
  3. LLM Token Counter and Context Budget Planner - Estimate Tokens and Visualize Context Window Usage
  4. Prompt Caching Breakpoint Planner Tool - Plan cache_control Placement and Prefix Reuse
  5. Claude Code Settings and Permissions Builder and Linter Tool - settings.json allow, deny, and ask Rule Generator and Validator
  6. Claude Code Hooks Configuration Builder Tool - Generate and Validate Hooks for settings.json
  7. Amazon Bedrock AgentCore Cedar Policy Builder and Tester - Client-Side Cedar Authorization Policy Editor and Evaluator
  8. JSONL Conversation and Transcript Viewer - Read and Search LLM Chat Logs
  9. AWS Signature Version 4 Request Signer and Explainer - Visualize SigV4 Signing Step by Step
  10. Content Security Policy Builder Tool - Build a CSP Header and Lint Weak Settings
  11. OAuth 2.0 and OIDC Flow Visualizer and PKCE Generator - Authorization Code, Client Credentials, and S256 Challenge Builder
  12. AWS Service Control Policy (SCP) Builder and Simulator - Offline Guardrail Evaluator
  13. AWS KMS Key Policy Builder Tool - Visual Builder and Linter for AWS KMS Key Policies
  14. Amazon DynamoDB Single-Table Design Helper Tool - Key, Sort Key and GSI Designer
  15. CORS Policy Tester Tool - Preflight and Access-Control Header Simulator
  16. Agent Skills Validator and Security Scanner Tool - Check SKILL.md Frontmatter Compliance and Flag Risky Patterns
  17. MCP Server Config Builder and Validator Tool - Generate and Validate Claude Desktop, Claude Code, VS Code, and Cursor MCP Configs
  18. llms.txt Generator and Validator Tool - Create llms.txt and llms-full.txt with Spec Compliance Checks
  19. SSL/TLS Certificate Decoder and Chain Inspector - X.509 PEM/DER Viewer
  20. DKIM / SPF / DMARC Record Builder and Validator - Email Authentication DNS TXT Record Generator
  21. Email Header Analyzer Tool - Received Chain, SPF/DKIM/DMARC, and Authentication-Results Inspector
  22. HTTP Security Header Analyzer Tool - CSP HSTS X-Frame-Options Audit with Grade and Recommendations
  23. Image Format Converter Tool - Client-Side HEIC WebP AVIF JPG PNG GIF BMP Batch Converter
  24. Markdown Table Visual Editor Tool - Spreadsheet-style GFM Table Builder with CSV/TSV/JSON Import
  25. JSONPath / JMESPath Query Tester Tool - Real-Time JSON Query Evaluator for AWS CLI --query
  26. API Request / curl Command Builder - Multi-Language HTTP Code Generator (curl, fetch, axios, requests, Go)
  27. Mermaid Diagram Live Editor Tool - Real-time Flowchart, Sequence, ER, and AWS Architecture Diagram Editor with SVG and PNG Export
  28. CSV Preview and Statistics Tool - In-Browser CSV Profiler with Type Inference and Histograms
  29. S3 Bucket Policy Generator Tool - Visual Builder and Linter for AWS S3 Bucket Policies
  30. PDF Text Extractor and Search Tool - Extract Text from PDF with Page Range and In-Browser Search
  31. SVG Optimizer Tool - Free Online SVG Cleaner and Minifier
  32. Character Encoding Converter Tool - Japanese Encoding Conversion and Mojibake Repair
  33. Line Ending / BOM Converter Tool - Free Online CRLF LF CR Newline and UTF-8 BOM Converter
  34. Password Strength Checker Tool - Entropy, Crack Time, and zxcvbn-based Password Diagnostic
  35. GraphQL Query Builder and Formatter Tool - SDL-Driven Query Generator and Validator
  36. WebAuthn / Passkey Test Tool - Browser-Side Registration and Authentication Inspector
  37. Athena Partition Projection Calculator - Partition Count and Path Preview Tool
  38. OpenAPI API Gateway Import Linter Tool - Validate OpenAPI Definitions for AWS API Gateway REST and HTTP APIs
  39. CodeBuild buildspec.yml Validator - Static Checker for Phases, Env, Artifacts and Reports
  40. AWS CLI Command Generator - Build AWS CLI Commands from GUI Form
  41. VTL Template Tester - Offline Velocity Template Language Evaluator for API Gateway and AppSync
  42. CloudTrail Event Viewer - Highlight, Filter, and Search AWS CloudTrail Events
  43. AWS Policy Diff Tool - Statement-Level IAM / S3 Bucket / KMS Key Policy Comparison
  44. S3 Lifecycle Policy Builder Tool - Generate JSON / XML / CloudFormation for S3 Rules
  45. EventBridge cron/rate Expression Validator - AWS Schedule Tester with Next Run Times
  46. S3 Storage Class Cost Comparison Tool - Compare Amazon S3 Storage Class Costs Across Access Patterns and Retention
  47. CloudWatch Logs Insights Query Builder - Visual Logs Insights Query Composer with Syntax Check
  48. CloudWatch Metric Filter Pattern Tester - Preview Matches and Extracted Values for Log Events
  49. Lambda Cost Estimator Tool - Monthly Cost Calculator with Tiered Pricing and Free Tier
  50. DynamoDB Capacity Calculator Tool - RCU/WCU and Monthly Cost Estimator
  51. Security Group Rule Overlap Detector - AWS SG Audit Tool
  52. VPC CIDR Subnet Planner - Multi-AZ Subnet Designer with CloudFormation/Terraform Output
  53. CloudFormation YAML JSON Converter Tool - Bidirectional Converter with Short-form Intrinsic Functions
  54. ARN Parser Builder Tool - AWS ARN Parser, Builder, and Batch Analyzer
  55. SAM Template Transform Preview - AWS::Serverless Transform Expander
  56. Step Functions ASL Validator and Visualizer - AWS State Machine Syntax Checker and Flow Diagram
  57. EventBridge Pattern Tester - Test Event Patterns Against Multiple Sample Events
  58. IAM Policy Least Privilege Analyzer - Detect Overly Permissive IAM Policies Offline
  59. IAM Policy Simulator (Offline) - Client-Side IAM Decision Diamond Evaluator
  60. CFN Intrinsic Function Resolver - Resolve CloudFormation Intrinsic Functions Locally
  61. CloudFormation Template Linter Tool - Client-Side cfn-lint Subset for YAML and JSON Templates
  62. Typing Speed Test and Practice Tool - WPM Test, Code Typing with Keystroke Heatmap
  63. Image to PDF Converter Tool - Convert Multiple Images to PDF with Smart Layout
  64. Barcode Generator Tool - Multi-Format 1D Barcode Creator with Batch Generation
  65. Image Watermark Tool - Add Text and Logo Watermarks to Photos with Batch Processing
  66. Digital Signature Pad Tool - Handwriting Signature Creator with PDF Signing
  67. Chart Graph Maker Tool - Interactive Data Visualization and Chart Creator
  68. Code Screenshot Generator Tool - Beautiful Code to Image Converter with Syntax Highlighting
  69. OG Image Generator Tool - Open Graph and Social Card Image Creator
  70. JSON to Type Generator Tool - Multi-Language Type Definition Generator with Smart Inference
  71. JSON Schema Generator Validator Tool - Multi-Sample Schema Inference with Format Detection
  72. JSON Diff Tool - Structural JSON Compare with JSONPath and RFC 6902 Patch
  73. Markdown Live Editor Tool - Real-time GFM Editor with Live Preview and Syntax Highlighting
  74. Schema.org JSON-LD Generator Tool - Structured Data Markup Generator with Google Rich Results Preview
  75. Color Palette Generator Tool - Harmony-Based Palette Creator with Image Extraction and Contrast Matrix
  76. PDF to Image Converter Tool - Convert PDF Pages to PNG JPEG WebP with DPI Control
  77. IP Subnet Calculator Tool - CIDR VLSM IPv4 IPv6 Network Calculator
  78. XML Formatter Validator Tool - Online XML Beautifier with XPath Tester and Tree Viewer
  79. PDF Merge Split Tool - Combine Split and Extract PDF Pages Online
  80. Image EXIF Metadata Viewer and Remover Tool - Privacy-Focused Photo Metadata Analyzer with GPS Map and Lossless Stripping
  81. Image Compressor Tool - Client-Side Image Compression Resizing and Format Conversion
  82. Favicon App Icon Generator Tool - Complete Favicon Package with ICO PNG and PWA Icons
  83. CSS Gradient Generator Tool - Linear Radial and Conic Gradient Maker with Multi-Layer Support
  84. Meta Tag OGP Generator Tool - Open Graph Twitter Card and Meta Tag Generator with Live Preview
  85. Number Base Converter Tool - Binary Decimal Hex Octal Converter with Bit Visualization
  86. CSV JSON Converter Tool - CSV to JSON and JSON to CSV Online Converter
  87. Lorem Ipsum Generator Tool - Multi-Style Dummy Text and Placeholder Content Generator
  88. HTML Entity Encoder Decoder Tool - Encode Decode and Reference HTML Special Characters
  89. SQL Formatter Tool - Online SQL Beautifier Minifier and Syntax Highlighter
  90. Chmod Permission Calculator Tool - Unix File Permission Calculator with Umask Support
  91. Word Character Counter Tool - Free Online Text Analyzer with Reading Time and Keyword Density
  92. URL Encoder Decoder Tool - Multi-Mode URL Encoding and Decoding with URL Parser
  93. Color Converter and WCAG Contrast Checker Tool - HEX RGB HSL Converter with Accessibility Testing
  94. Cron Expression Parser and Builder Tool - Schedule Generator with Next Run Times
  95. Diff Text Compare Tool - Free Online Side-by-Side Text Difference Checker
  96. Regex Tester Tool - Online Regular Expression Tester and Explainer
  97. JWT Encoder Tool - JSON Web Token Generator and Signer
  98. JWT Decoder Tool - JSON Web Token Inspector and Debugger
  99. YAML JSON Converter Tool - Bidirectional YAML and JSON Online Converter
  100. QR Code Generator and Reader Tool - Create and Scan QR Codes Online
  101. UUID ULID Generator Tool - Generate and Decode UUID v4, v7 and ULID
  102. JSON Formatter Validator Tool - Online JSON Beautifier Minifier and Tree Viewer
  103. Text Case Converter Tool - Free Online Text Transformation and Case Changer
  104. Unix Timestamp Converter Tool - Epoch Time and Date Converter with Timezone Support
  105. Base64 Encoder Decoder Tool - Text and File Base64 Encoding with Data URI Support
  106. Password Generator Tool - Secure Random Password and Passphrase Generator with Strength Checker
  107. Hash Generator Tool - Multi-Algorithm Hash Calculator with File Support
  108. Markdown HTML Converter Tool - Client-Side Parser and Free Online Converter
  109. JavaScript CSS Minifier Tool - Free Online Code Minification and Compression
  110. IP Range to CIDR Converter Tool - Free Online Network Calculator
  111. AES Encryption Decryption Tool - Client-Side Crypto Cipher and Free Online Encryptor Decryptor
  112. Free Website Speed Test Tool - Lighthouse and PageSpeed Insights Analysis

References:
Tech Blog with curated related content

Written by Hidekazu Konishi