Developer Tools
12 tools
Developer utilities for JSON, Cron, HTTP, URLs, UUIDs, subnets, and other checks that come up repeatedly during development and operations. Designed for quick validation before opening heavier tools.
How to choose a tool
Start with the tool closest to your task, then use the related tools near the bottom of each page when the workflow continues. Each tool page includes features, usage steps, and FAQs so users can understand what the tool does before relying on the result.
Developer Tools
JSON Formatter
Format, minify, and validate JSON. Syntax highlighting supported.
Cron Expression Editor
Create cron expressions visually. Preview next execution times.
HTTP Status Reference
Search and reference all HTTP status codes with descriptions and examples.
Dummy Data Generator
Generate dummy data (names, emails, etc.) in JSON/CSV format.
Markdown Preview
Real-time preview. HTML export supported.
URL Parser
Parse URL query parameters into a table format and edit them.
HTML Entity Converter
Escape/unescape HTML special characters.
Anniversary Calculator
Calculate dates for specific day counts from a start date. 100th, 1000th day anniversaries.
Image Combiner
Combine multiple images horizontally, vertically, or in a grid.
YAML ⇄ JSON Converter
Convert between YAML and JSON with indent control.
UUID生成
UUID v4・v7を一括生成。ハイフン・大文字小文字切替可能。
YAML ⇄ JSON変換
YAMLとJSONを相互変換。インデント調整対応。