All tools

CSV to JSON

Convert CSV rows to a JSON array of objects locally in your browser.

JSON Formatter

Beautify and format JSON with selectable indentation, instantly in your browser. No upload, no sign-up.

JSON Minifier

Compress JSON to a single compact line to save bytes in API responses and config files.

JSON Query

Query, filter and transform JSON with jq expressions, locally in your browser. No upload, no sign-up.

JSON to CSV

Convert a JSON array of objects to CSV locally in your browser.

JSON to TypeScript

Generate TypeScript interfaces and types from a JSON document, locally in your browser. Nested interfaces, arrays, optional fields and unions — no upload.

JSON Validator

Validate JSON syntax and get the exact line and column of the first error, plus document statistics.

JSONPath Tester

Test a JSONPath expression against your JSON and see every matching node with its path. Runs in your browser, with filters supported.

YAML Validator

Validate YAML and locate syntax errors with line, column and a code frame — locally in your browser, nothing uploaded.

Base64 Encoder / Decoder

Encode and decode Base64 text locally in your browser, UTF-8 safe.

QR Code Generator

Create QR codes locally in your browser — no signup, no watermark, no tracking. Download as clean SVG or PNG.

URL Encoder / Decoder

Percent-encode and decode URL components locally in your browser.

Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes locally in your browser.

HMAC Generator

Generate keyed HMAC-SHA1, SHA-256, SHA-384 and SHA-512 signatures locally in your browser. For webhooks, APIs and signed messages.

JWT Decoder

Decode and inspect JWT header and payload locally in your browser — without verifying the signature.

Signing Key Generator

Generate RSA, ECDSA and Ed25519 signing key pairs locally in your browser, exported as JWK and PEM. For JWT and application signing — not SSH keys or certificates.

DNS Lookup

Ask several public resolvers the same DNS question at once and see where they disagree. A, AAAA, CNAME, MX, TXT, NS, SOA and CAA, in your browser.

Internet Speed Test

Measure your connection in the browser: latency, jitter, download and upload speed. Powered by M-Lab's open NDT7 measurement network.

Open Graph Checker / Generator

Check a page's Open Graph and Twitter meta tags, preview the card on Facebook, X, LinkedIn and Google, and get the missing tags generated for you.

Website Status Checker

Check whether a website is up — or trace where a link goes. Get HTTP status, response time, every redirect hop and the final URL.

Code Formatter

Format and beautify JavaScript, TypeScript, JSON, CSS, HTML, Markdown, YAML, XML and SQL, locally in your browser. No upload, no sign-up.

HTML Editor

Edit HTML visually or directly in the source — a browser-based WYSIWYG HTML editor with live source editing. No upload, no sign-up.

Regex Tester

Test regular expressions against text and see every match, locally in your browser.

Text Counter

Count words, characters, lines, sentences and paragraphs of your text, locally in your browser.

Text Diff

Compare two texts or code snippets side by side, line by line, entirely in your browser. See added, removed and unchanged lines — no upload.

Cron Expression

Validate, explain, build and preview the next runs of a cron expression — with timezone and DST handling, locally in your browser.

Unix Timestamp Converter

Convert between Unix timestamps and human-readable dates, locally in your browser.

UUID Generator

Generate RFC 4122 version 4 UUIDs in bulk and copy them with one click, entirely in your browser.

.env Validator

Check a .env file for duplicate keys, invalid names, quoting problems and undefined ${VAR} references. It runs in your browser and nothing is uploaded.

Find Command Builder

Build a GNU find command with filters for name, path, size, time, owner and permissions — and see what every flag does. Nothing is executed.

Docker Compose Builder

Build a docker-compose.yml from a form and get it checked for common mistakes: privileged containers, database ports published to the world, orphan volumes. Nothing is executed.

rsync Command Builder

Build an rsync command with excludes and SSH options, and get the trailing-slash rule explained. --delete comes with a warning and dry-run enabled.