Developer Toolkit

Format, validate, and minify JSON strings directly in your browser. Checks syntax and reports parse errors while preserving number formatting and key order.

Converts character strings and binary data to hexadecimal, binary, Base64, URL encoding, etc. in real time.

Input the source code, generate and export images with beautiful gradient backgrounds and editor-like decorations.

Images will be cropped and resized according to the recommended size of each SNS platform (X, Instagram, YouTube, etc.).

Generates Lorem Ipsum text for layout confirmation and random text in the style of classical Japanese literature (such as Aozora Bunko).

Remove unnecessary spaces, line breaks, and comments from HTML, CSS, and JavaScript code to minimize file size.

Decode and inspect JWT headers and payloads directly in your browser. Displays Base64URL-decoded JSON structure and expiration status without performing cryptographic signature verification.

Test JavaScript regular expressions directly in your browser against custom text. View match highlights, capture groups, and index positions with support for standard flags.

Breaks down complex URLs into protocols, hosts, paths, and query parameters, then edits and reconstructs the parameters in a grid format.

Visually adjust the shadow direction, blur, diffusion, color (RGBA), opacity, and inner shadow (Inset), and output CSS code.

You can create linear and radial gradations and intuitively add, move, and delete color stops.

Special characters (<, >, &, \

This is an editor that allows you to display and check text entered in Markdown notation alongside an HTML preview in real time.

Convert a single YAML document to JSON or convert JSON to YAML locally. Nested objects and arrays are supported, with explicit input and output limits.

Converts CSV data from spreadsheets and databases into JSON or XML formats that are easy to handle programmatically.

It formats difficult-to-read SQL statements beautifully and easily by capitalizing reserved words, adding appropriate line breaks, and inserting indents.

Assemble an HTTP request (method, content-type, various authentications, etc.) and visualize the generated headers and expected responses.

Performs indentation formatting of XML text and syntax checking (identifying error lines) such as missing closing tags on the browser.

Automatically generate a specified number (up to 500) of random and unique IDs (UUID v4 or v1) at once.

Automatically converts text and HTML source code to each other, such as converting text line breaks to <p> tags and URLs to <a> links.

Just select the action you want to perform, such as branching or undoing a commit, from the menu and the correct Git command will be automatically generated.

We will construct and explain the correct cron execution description (* * * * *) by specifying the minute, hour, day, month, and day of the week from intuitive selection boxes.

Define the number of rows and columns and gap width in the on-screen grid, and generate CSS Grid layout code interactively.

Contrast ratio is calculated from text color and background color, and compliance with WCAG 2.1 standards (AA/AAA) is determined in real time.

Automatically calculates network address, host range, and broadcast address from IP address and subnet mask.

Automatically converts regular HTML code into JSX code for React components (className replacement for class, htmlFor replacement for for, inline style objectification, self-closing tag completion, etc.).

Easily convert basic shell commands and script structures (file moves, string searches, environment variable settings, etc.) between Bash and PowerShell, and display a syntax comparison guide.

Use the border property trick to specify the size, orientation, and color of triangles (up, down, for callouts, etc.) that can be drawn using only CSS, and get CSS and Tailwind code.

Converts between the three main configuration file formats: JSON, YAML, and TOML with syntax validation.

Load your font file (.ttf / .otf / .woff / .woff2) into the browser, perform a display test, and generate Base64 code for CSS embedding.

Automatically builds definition files for SSH connection settings (~/.ssh/config) and Git global environment settings (~/.gitconfig) using form input.

Based on the base color, a beautiful palette is automatically calculated based on color harmony theory (complementary colors, analogous colors, triads, divisive complementary colors, tetrads, monochromes, etc.).

Generate the virtual host settings (nginx.conf) for the web server Nginx. Supports cache, Gzip, SSL, and reverse proxy.

Select the target environment such as Node.js, Python, Go, macOS, Windows, VSCode, IntelliJ, Unity, etc. and create a clean .gitignore file.

Visually design the docker-compose.yml file that defines a multi-container configuration using form operations.

Specify the position, size, transparency, and rotation along the timeline, and output the @keyframes CSS code while previewing the animation of the change.

It analyzes the syntax of the input regular expression and draws state transitions (state machines) and tree structures on the canvas to visualize "which parts are functioning and how."

It reads JSON data such as API responses and automatically constructs TypeScript interface definitions, including nested objects.

A comprehensive reference catalog of HTTP status codes compliant with RFC 9110. You can instantly search for Japanese explanations, detailed meanings, corresponding RFC sections, and mock examples of common API responses.

In addition to aligning messy GraphQL queries and schema (SDL) indentations, neatly formatting, syntax checking, and compressing (Minify), you can easily design schemas using GUI operations.

Create a table using a GUI operation such as a spreadsheet or Excel, and automatically output Markdown table text with neatly aligned widths.

Generates a CSS clamp() expression that smoothly scales the font size according to the minimum and maximum screen width.

Automatically converts the terminal's curl command into a request code using JavaScript's standard Fetch API or Axios.

You can generate and download color badges (Shields.io style) for flat and beautiful parameter display in SVG format, perfect for GitHub READMEs, etc.

Specify a JSONPath expression or JQ-style filter from a large amount of JSON data to instantly extract specific data nodes and display them in a tree.

Mutually converts and restores text characters to various Unicode escape codes (\\uXXXX, \\u{XXXX}, HTML numeric character reference, %uXXXX).

This is a generator that can automatically create and output beautiful pixel art drawn using only one HTML element and the box-shadow property.