Developer calculators
21 free tools
The small utilities you reach for mid-code — Base64, JSON, and number bases — running locally so nothing you paste leaves your browser.
Encode text to Base64 or decode Base64 back to text, in your browser.
Type an identifier or phrase and see it rewritten in camelCase, PascalCase, snake_case, kebab-case, and CONSTANT_CASE side by side, right in your browser.
Paste CSV where the first row is your headers and get back a pretty-printed JSON array of objects — quoted fields with embedded commas handled — all in your browser.
Turn hex bytes into readable text or text into hex, flipping direction with a single toggle — spaces, colons, and 0x prefixes are ignored — all in your browser.
Escape <, >, and & into HTML entities so text renders as text, or decode entities back to characters.
Type or pick an HTTP status code to see its name, its 1xx-5xx category, and a short plain-English meaning, from a built-in reference of common codes.
Validate, prettify, and minify JSON with clear error messages.
Escape a string so it drops cleanly inside JSON, or unescape a JSON string back to raw text.
Paste a JSON array of flat objects and get spreadsheet-ready CSV, with the header row built from your keys and any commas or quotes escaped for you — all in your browser.
Paste JSON and get clean, indented YAML back, with objects, arrays, and every scalar type handled and clear errors for invalid input — all in your browser.
Paste a JSON Web Token to see its header and payload decoded and pretty-printed — decoding only, no signature verification, all in your browser.
Sort lines of text A–Z or Z–A, with options to ignore case and drop blank lines.
Convert numbers between binary, octal, decimal, and hexadecimal.
Paste a full URL or just a query string and read every parameter as a table of decoded key/value pairs — repeated keys and percent-encoding handled — right in your browser.
Escape a string so it's safe inside a JSON or JavaScript literal — newlines, tabs, quotes, backslashes — or flip the toggle to unescape, all in your browser.
Paste two blocks of text and see which lines were added, removed, or changed, color-coded line by line with counts — all in your browser.
Convert text into binary using character codes, or turn space-separated binary back into text.
Convert Unix epoch seconds to a readable UTC date and back, with the current timestamp ticking live.
Percent-encode text for safe use in URLs, or decode an encoded URL back to readable text.
Paste a URL to break it into protocol, host, port, path, hash, and a table of query parameters, using your browser's built-in URL engine.
Paste indentation-based YAML — maps, lists, and scalars — and get pretty-printed JSON back, with a clear message on malformed input, all in your browser.
Frequently asked questions
Do these developer tools send my data anywhere?
No. Encoding, formatting, and converting all happen locally in your browser, so you can paste an API response, a token, or config without it ever leaving your machine.
What can I do here?
Encode and decode Base64, format or minify JSON with proper error messages, and convert numbers between binary, octal, decimal, and hexadecimal — the small jobs that come up constantly while coding.
Does the JSON formatter validate too?
Yes. If the JSON is malformed, it tells you what went wrong instead of silently failing, so you can spot the missing comma or bracket fast.