Client-side utilities
Format, encode, generate, and inspect — without sending a single byte to a server. No accounts, no tracking of your input, no upload step. Everything below runs on your machine, in this tab.
Directory
Validate and pretty-print JSON, with clear error locations when it doesn't parse.
InspectExplore JSON as a collapsible tree and copy any value's path or raw value.
GenerateSet the URL, method, headers, and body, and get a copy-ready curl command.
TestTest patterns against sample text with live match highlighting and group capture.
GenerateGenerate v4 UUIDs individually or in bulk, ready to copy.
EncodeConvert text or files to and from Base64 instantly.
EncodePercent-encode or decode strings for safe use in URLs.
ConvertConvert between HEX, RGB, HSL, and OKLCH with a live preview swatch.
GenerateBuild linear and radial gradients visually, copy the CSS output.
ConvertConvert between epoch seconds, milliseconds, and readable dates with a live clock.
ExplainPaste a cron expression, get a plain-English schedule description.
CompareCompare two blocks of text and see additions and deletions inline.
PreviewWrite Markdown on one side, see the rendered HTML on the other.
GenerateGenerate placeholder text by word, sentence, or paragraph count.
DecodeDecode a JSON Web Token's header and payload without verifying it against a server.
GenerateHash text or files with MD5, SHA-1, and the full SHA-2 family. Runs locally.
GenerateCryptographically random passwords with strength and entropy readouts.
ConvertConvert text to camelCase, snake_case, kebab-case, Title Case and more.
ConvertConvert between decimal, hex, binary, octal and base-36 — exact at any size.
ConvertFlatten JSON arrays into RFC-4180 CSV you can download or paste.
CalculateGet the network, broadcast, usable range and host count for any IPv4 CIDR block.
Why client-side
Most "online tools" quietly send your input to a backend to process it — which is a real problem if you're pasting API keys, tokens, customer data, or anything else you wouldn't want to leave your machine. Every tool on DevKit runs entirely in JavaScript, in your browser tab. Closing the tab clears everything. There's nothing to intercept because nothing is ever sent.