Developer Tools
The small stuff that eats up a developer's day: looking up HTTP status codes, generating UUIDs, writing cron expressions, checking MIME types, parsing User-Agent strings, or scaffolding TypeScript types from JSON. Bookmark this page — it's faster than digging through docs.
Developer Tools
UUID Generator
Free online UUID generator creating RFC 4122 compliant unique identifiers. Supports UUID v1, v4 versions, batch generation.
Token Counter
Free online token counter tool to estimate token count in AI models like GPT and Claude. Helps control prompt costs for API calls.
HTTP Status Code Reference
Free online HTTP status code reference with all standard codes. Search and filter by category, quickly find 1xx to 5xx status code meanings.
MIME Types Reference
Free online MIME type lookup tool. Find MIME types by file extension, search and filter by category — documents, images, audio, video.
Git Command Reference
Free online Git commands cheat sheet with most commonly used Git commands. Organized by category with search and filter for quick Git command lookup.
ASCII Table
Free online ASCII table with control characters, printable characters, and extended codes. Search and filter ASCII values for quick lookup.
Cron Expression Generator
Visual builder supporting seconds and Quartz extensions.
JSON to TypeScript
Free online JSON to TypeScript converter auto-generating interfaces. Supports nested objects, arrays and union types.
JSON Schema Generator
Free online JSON Schema generator creating standards-compliant schemas from JSON. Infer nested objects, arrays and required fields.
Excel Data Generator
Online Excel test data generator for name, phone, ID, date, money. Generate mock data and export .xlsx with custom column rules. Local, private.
CSV Data Generator
Online CSV test data generator for name, phone, ID, date, money. Generate mock data and export .csv with custom rules, delimiters and BOM. Local.
UA Parser
Free online User-Agent parser tool. Instantly identify browser, operating system, and device info from any UA string. Essential tool for web developers.
Mermaid Editor
Free online Mermaid diagram editor for flowcharts, sequence diagrams, class diagrams, ER diagrams, Gantt charts, mind maps, and live PNG/SVG export.
Demo Example
Server-side rendered (SSR) demo page showing how the front end fetches data from a back-end API at request time, ideal for fast, fully SEO-indexable pages.
What this category can do
Developer tools provide small references and generators needed during implementation: UUIDs, token counts, HTTP status codes, MIME types, Git commands, ASCII tables, Cron expressions, JSON Schema, TypeScript types, User-Agent parsing and Mermaid diagrams. This category supports coding and debugging details rather than end-user document conversion.
Most tools process input in the browser when possible. For files, tokens, documents or network checks, review the selected tool before using sensitive data.
Common use cases
- Generate UUIDs, Cron expressions or TypeScript types while building a feature.
- Look up HTTP status codes, MIME types, ASCII values or Git commands during debugging.
- Parse User-Agent strings, estimate token usage or sketch Mermaid diagrams for docs.
FAQ
Are generated UUIDs guaranteed unique?
They are designed to make collisions extremely unlikely, but no random identifier can be absolutely guaranteed forever.
Why should generated TypeScript be reviewed?
Types inferred from one JSON sample may miss optional fields, unions or production variants.
Do Cron expressions work the same everywhere?
No. Some schedulers include seconds or support special syntax. Check the target platform.
Why is token counting approximate?
Tokenization depends on the model and request format. Use counts as estimates unless the tool matches the exact model.
Related Categories
Data Formatting
Messy, minified code slowing you down? Paste it in, pick your language, and get clean, properly indented output in a snap. Covers JSON, XML, YAML, HTML, CSS, JavaScript, SQL, Java, and Python — no plugins, no sign-up.
Text Processing
Writing, editing, or cleaning up text? Test regular expressions with live match highlighting, diff two blocks side by side, count words and characters, switch between letter cases, preview Markdown, strip duplicate lines, or convert Chinese characters to Pinyin.
Network Tools
Troubleshooting connectivity? Check your public IP, ping a host, scan open ports, query WHOIS records, verify SSL certificates, or test WebSocket connections. Run network diagnostics without opening a terminal.
