Developer tools for data that should stay local
Format, decode, inspect, and convert data directly in your browser.
Browse all tools
Open a tool directly when you already know what you need.
JSON Formatter & Validator
Format, validate, and minify JSON with clear syntax hints.
Base64 Encoder & Decoder
Encode text as Base64 or decode Base64 back to UTF-8 text.
URL Encoder & Decoder
Encode URL components or decode percent-encoded query strings.
Hash Generator
Create MD5, SHA-1, SHA-256, and SHA-512 hashes from text.
UUID / GUID Generator
Generate one UUID v4 or create a batch for fixtures and test data.
Regex Tester
Test regular expressions with real-time highlighting and match counting.
JWT Decoder
Decode JWT headers and payloads, then check expiration claims.
Diff Checker
Compare two text blocks and highlight line-by-line changes.
Color Converter
Convert HEX, RGB, and HSL values with a live color preview.
Unix Timestamp
Convert Unix timestamps to dates and vice versa. Shows local, UTC, ISO, and relative time.
Markdown Preview
Draft Markdown and preview the rendered HTML as you write.
HTML Entity Encoder
Escape special characters for HTML or decode entities back to text.
Word Counter
Count words, characters, lines, paragraphs, and estimated reading time.
Lorem Ipsum Generator
Generate placeholder paragraphs, sentences, or words for mockups.
Code Minifier
Lightly minify CSS and JavaScript snippets for compact examples.
Chmod Calculator
Calculate Unix file permissions and copy the matching chmod command.
Why DevTools Box?
DevTools Box brings common debugging and data-cleanup tasks into a focused browser workspace: checking a payload, decoding a token, generating an identifier, comparing text, or converting a timestamp. The interface stays quiet so the data and the next action stay easy to see.
Use Smart Paste when you want the site to suggest a starting point, or open a tool directly when you already know the job. Each tool keeps the workflow short: paste, inspect, transform, copy, and move on.
Popular tools
The most common workflows are covered first: a JSON formatter and validator for API responses, a Base64 encoder and decoder for text payloads, a URL encoder for query strings, and a hash generator for MD5, SHA-1, SHA-256, and SHA-512 digests.
The toolbox also includes a regex tester, JWT decoder, Unix timestamp converter, text diff checker, color converter, plus focused writing utilities such as a word counter and lorem ipsum generator.
When to use it
DevTools Box is useful for quick checks while coding, debugging API payloads, preparing examples, validating copied data, or converting values during documentation and support work. There is no project setup or account step; open the page and use the tool.
Frequently Asked Questions
Is DevTools Box free to use?
Yes. The tools are available without an account or usage limits.
Do these tools require uploads?
No. The current tools run as static pages, and transformations are handled by client-side JavaScript.
Do I need to create an account?
No. Open a tool and start working.
Can I use these tools on mobile?
Yes. The layout adapts for smaller screens, and the sidebar becomes a mobile menu.