dools.dev
Free Developer Tools & Online Utilities
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ADR Generator
Generate Architecture Decision Records from a template.
AI Tokenizer
Visualize and count tokens for GPT, Claude, and Gemini models.
Argon2 Hash Generator
Generate secure Argon2 password hashes
Argon2 Hash Verifier
Verify passwords against Argon2 hashes
Azure SAS Token Decoder
Decode and inspect Azure Shared Access Signature tokens.
Base64 Text
Text ↔ Base64
Case Converter Pro
Convert between camelCase, snake_case, kebab-case and more.
Certificate Parser
Analyze and inspect X.509 certificates
CIDR Range Visualizer
Visualize and compare multiple CIDR ranges side by side.
Circuit Breaker Visualizer
Visualize circuit breaker state transitions and failure patterns.
Code → Image
Create PNG/JPEG/WEBP from code with highlighting and theme
Coin Flipper
Let the coin flipper randomly pick between two options when you can't decide.
Converters
Convert between JSON, YAML, TOML, XML
Cron Parser
Parse cron expressions and see next execution times
CSV Schema Detector
Detect column types and schema from CSV data.
Curl Command Builder
Build curl commands visually with headers, auth, and body options.
Database Connection String Builder
Build connection strings for SQL Server, Azure SQL, PostgreSQL, MySQL, and SQLite.
Email Header Parser
Inspect Received hops and auth results
Fake OAuth Tokens
Generate fake JWT/OAuth tokens for development and testing.
Favicon Generator
Create favicon sets from an image
File Checksum Calculator
Calculate SHA-1, SHA-256, SHA-384, SHA-512 checksums of any file.
Formatters
Formatting for JSON, XML, YAML, TOML, SQL
Funny Git Branch Name Generator
Generate entertaining and creative branch names for your repos.
GitIgnore Composer
Compose .gitignore files from common templates.
GPT Clean
Cleans copied ChatGPT / AI text
Gzip
Compress & decompress (Gzip)
Hash Generator
Compute hash from text
HTML Color Picker
Pick HEX/RGB/HSL, check contrast, and keep a palette
HTML Encoder/Decoder
Encode & decode HTML entities
HTTP Cookie Parser
Parse and inspect Set-Cookie and Cookie headers.
HTTP Error Code Explainer
Look up and understand HTTP status codes.
HTTPS Certificate Generator
Create HTTPS certificates signed by your Root CA
Image Compressor
Reduce / optimize image size
Image Converter
Change format between PNG/JPG/WebP
Image ↔ Base64
Convert images to/from Base64
Invisible Character Viewer
Detect and highlight invisible Unicode characters hidden in text.
IP Address Calculator
Calculate subnet mask, network, broadcast and more from IP/CIDR notation.
JSON Flatten / Unflatten
Flatten nested JSON to dot notation or unflatten back to nested structure.
JSON Schema Generator
Generate JSON Schema from sample JSON data.
JWT Signature Validator
Validate JWT signatures with HMAC and RSA keys.
JWT Token Tool
Decode, validate and inspect JWT tokens
License Generator
Generate open source license files (MIT, Apache, GPL, BSD, ISC and more).
LinkedIn Text Formatter
Format text for LinkedIn posts with bold, italic, and more
Lorem Ipsum Generator
Generate placeholder text
Markdown
Live preview with GFM support
Mermaid Studio
Create and export Mermaid diagrams with themes, styles, and live preview
OpenAI Tool Definition Builder
Build OpenAI function/tool definitions visually.
OpenAPI Editor
Interactive editor for OpenAPI 3.x and Swagger 2.0 specs with live documentation preview.
Outlook Signature Builder
Design professional HTML email signatures for Outlook.
Password Generator
Generate secure passwords
PEM Formatter
Convert PEM blocks and single-line key strings
PlantUML Editor
Edit and download PlantUML source locally.
QR Code Generator
Generate QR code from text
RAG Chunk Size Simulator
Simulate and visualize RAG chunking strategies.
Random String Generator
Generate secure random strings, tokens, API keys and codes in your browser.
Rate Limit Simulator
Simulate API rate limiting with token bucket and sliding window algorithms.
Regex Explainer
Explain regex patterns and preview matches
Root CA Generator
Create a self-signed Root Certificate Authority
Semantic Version Calculator
Parse, compare, and bump semantic versions.
SNK Key Generator
Generate .NET strong-name key files and a Directory.Build.props snippet.
Storage Size Converter
Convert between bytes, KB, MB, GB, TB and binary/decimal units.
SVG Optimizer
Optimize and minify SVG files.
SVG to React Component
Convert SVG markup into React/TSX components.
Swagger Editor
Edit and validate Swagger/OpenAPI 2.0 definitions.
Text Diff
Compare two text blocks
Text to Hash
MD5 / SHA hashing
Time → Cron
Convert schedule times into cron expressions
Timestamp Difference Calculator
Calculate the exact difference between two timestamps or dates.
Token Cost Calculator
Calculate token counts and costs for LLM API calls.
TOON Converter
Convert JSON, YAML, TOML to TOON format
Unicode Normalizer
Normalize Unicode text to NFC, NFD, NFKC or NFKD forms.
URL Encoder/Decoder
Safely encode & decode URLs
UUID / GUID Generator
Generate random UUID
Validators
Validate JSON, XML, YAML, TOML
X / Twitter Text Formatter
Format text and code snippets for X (Twitter) posts — with Unicode styling and a live character counter