Offline developer tools

Browse developer tools

Every input and output stays in your browser.

Choose a tool by the data you need to inspect, not by the format you expect to get back.

Format & convert

JSON Formatter

Format, minify, and sort JSON locally without changing your input.

Base64 Encoder & Decoder

Encode UTF-8 text to standard or URL-safe Base64 and decode it locally.

URL Inspector

Parse, build, and encode HTTP(S) URLs locally.

Timestamp Converter

Convert timestamps and IANA time zones locally.

JSON to TypeScript

Turn JSON into predictable TypeScript interfaces or type aliases locally.

CSV to JSON Converter

Convert CSV or TSV to JSON locally. Preserve leading zeros, long identifiers and text values; catch malformed rows before copying or downloading.

HTML Entity Encoder & Decoder

Encode HTML-sensitive text or decode one layer of character references locally, without rendering the result as markup.

XML Formatter & Well-Formedness Checker

Format XML and check its structure locally. Preserve mixed text and inspect parser errors without uploading your document.

Email Address Normalizer

Trim address lists and normalize domain casing without changing local parts.

Text and Binary

Convert UTF-8 text to bytes shown as eight-bit binary, or decode byte groups.

Unicode Code Points

Show Unicode code points for text and reconstruct text from U+ values.

NATO Phonetic Alphabet

Spell Latin letters and digits with standard radio words.

URL Slug Generator

Convert a short title into a lowercase URL path segment.

Case Converter

Convert words to camelCase, PascalCase, snake_case, and kebab-case.

JSON to CSV

Export a JSON array of flat objects as RFC-style quoted CSV text.

Roman Numeral Converter

Convert standard integers from 1 to 3999 to Roman numerals and back.

Temperature Converter

Convert Celsius, Fahrenheit, and Kelvin with absolute-zero checks.

Integer Base Converter

Convert signed integers between bases 2 and 36 without floating-point rounding.

List Converter

Turn line-separated items into a quoted CSV row or a JSON array.

IPv4 Address Converter

Convert dotted-decimal IPv4 addresses to unsigned decimal, hexadecimal, and binary forms.

Color Format Converter

Convert opaque six-digit sRGB hex colors to RGB and HSL notation.

JavaScript String Escaper

Represent text as JavaScript code points for inspection or source embedding.

YAML to JSON

Parse one YAML document and format its data as JSON.

JSON to YAML

Format a JSON value as a YAML document.

YAML to TOML

Convert a YAML mapping into a TOML document when its values are representable.

TOML to YAML

Parse TOML and present its data as YAML.

JSON to TOML

Convert a JSON object to TOML with explicit errors for unsupported values.

TOML to JSON

Parse TOML tables and values into formatted JSON.

XML to JSON

Parse well-formed XML into a JSON tree with attributes and text nodes.

JSON to XML

Build XML from a JSON object with one root element.

Markdown to HTML

Convert Markdown syntax to HTML source shown as inert text.

SQL Formatter

Format general SQL whitespace and keyword casing for easier review.

AES-GCM Text Encryption

Encrypt or decrypt a small text payload locally with PBKDF2 and AES-GCM.

File and Base64

Encode a small local file as Base64 or download decoded Base64 bytes.

HTML Rich Text Editor

Edit short rich text locally and copy sanitized HTML source.

Docker Run to Compose

Translate common docker run flags into a reviewable Compose YAML service.

YAML Formatter

Parse YAML and produce consistently indented, readable YAML.

Generate content

UUID Generator

Generate UUIDv4 or time-ordered UUIDv7 batches locally with secure browser randomness.

Hash Generator

Create MD5 and SHA checksums for text or local files without uploading them.

Password Generator

Generate a password in your browser with cryptographically secure randomness.

Open Graph Meta

Create escaped canonical, Open Graph, and Twitter Card tags with a local text preview.

Fluid Typography Clamp Generator

Generate a fluid font-size clamp() from two viewport widths and font sizes. Preview endpoints and copy CSS locally.

CSS Cubic Bézier Editor

Shape a CSS cubic-bezier() curve visually, compare its motion with linear easing, and copy transition CSS. All editing stays in your browser.

CSS Grid Generator

Create named CSS Grid areas on a visual map, preview the rendered layout, and copy matching CSS and HTML locally.

CSS Flexbox Generator

Preview real Flexbox layout at different container sizes, tune each item, and copy CSS and sample HTML locally.

CSS Gradient Generator

Build linear or centered radial gradients with two to five color stops, preview native CSS, and copy a safe rule locally.

CSS Box Shadow Generator

Build up to four CSS box-shadow layers, compare light and dark previews, tune inset and opacity, and copy CSS locally.

Basic Auth Header

Create an HTTP Basic authorization header from a username and password in your browser.

Numeronym Generator

Shorten long words into forms such as i18n and a11y.

Random Port Number

Suggest a random unprivileged TCP or UDP port from 1024 to 65535.

Local MAC Address Generator

Generate a locally administered, unicast 48-bit MAC address.

Random Token Generator

Generate 256 bits of random data as hexadecimal and URL-safe Base64.

Placeholder Text Generator

Create short Latin placeholder paragraphs for layout tests.

IPv6 ULA Prefix

Generate a random fd00::/8 local IPv6 /48 prefix.

SVG Placeholder

Generate a small inline SVG rectangle with dimensions shown as text.

ULID Generator

Create a 26-character, time-sortable ULID with secure randomness.

Cron Schedule Generator

Create a five-field Cronie expression from a simple daily, weekly, monthly, or interval schedule.

ASCII Text Art

Render short Latin text as FIGlet-style ASCII art in the browser.

bcrypt Hash and Check

Hash a disposable test password with bcrypt or compare it against a bcrypt hash locally.

BIP39 Test Mnemonic

Generate a BIP39 English mnemonic for disposable tests or check a phrase's checksum locally.

QR Code Generator

Encode short text or a URL as a local SVG QR code.

Wi-Fi QR Code

Create a local Wi-Fi connection QR code from SSID, password, and security mode.

HMAC-SHA-256

Calculate an HMAC-SHA-256 tag for a test message with a local secret key.

RSA Test Key Pair

Create a 2048-bit RSA-OAEP key pair in the browser and export PEM test keys.

Local Camera Recorder

Record a short camera clip in the browser and download it without uploading.