ToolHub
Free online tools — fast, secure, privacy-first

Useful, fast and privacy-friendly online tools

ToolHub offers free online tools for developers and everyday users, including JSON formatter & validator, Base64 encoder/decoder, and octal-escaped string decoder. Everything runs in your browser.

Tools

All tools run in your browser. We do not collect your data. Available now: JSON formatter & validator, Base64 encoder/decoder, octal-escaped string decoder.

Encoding

Octal-Escaped String Decoder

Decode \345\255\246-style octal-escaped bytes back to UTF-8 text

Open tool

Base64 Encoder / Decoder

Encode and decode UTF-8 text to / from Base64 (standard or URL-safe).

Open tool

URL Encoder / Decoder

Percent-encode and decode URL components — UTF-8 safe, RFC 3986.

Open tool

Data formats

JSON Formatter & Validator

Pretty-print, minify and validate JSON. Tolerates comments and trailing commas.

Open tool

YAML ↔ JSON Converter

Convert YAML to JSON and back. Validates indentation and structure.

Open tool

CSV ↔ JSON Converter

Convert CSV / TSV data to JSON and back. RFC 4180 compatible.

Open tool

Crypto & hash

Hash Calculator (MD5 / SHA-1 / SHA-256 / SHA-512)

Compute MD5, SHA-1, SHA-256 and SHA-512 of any text — locally.

Open tool

JWT Decoder / Inspector

Decode and inspect JSON Web Tokens. Header, payload and signature.

Open tool

Generators

UUID & NanoID Generator

Generate UUID v4, time-ordered UUID v7 and NanoID. Batch up to 1000.

Open tool

QR Code Generator

Generate QR codes from text or URLs. SVG download, fully offline.

Open tool

Text

Text Diff & Compare

Compare two texts line by line. Free, fast, runs in your browser.

Open tool

Regex Tester

Test JavaScript regular expressions live. Highlights all matches.

Open tool

Markdown Live Preview

Markdown editor with side-by-side live preview, TOC, and safe HTML export.

Open tool

Date & time

Unix Timestamp Converter

Convert between Unix timestamps and ISO / RFC dates. Auto-detects unit.

Open tool

Cron Expression Parser

Explain a cron expression and preview the next runs.

Open tool

Media

Image Compressor & Converter

Compress and convert JPG / PNG / WebP / AVIF — locally, no upload.

Open tool

Image Stitcher (Long Image / Collage)

Combine multiple images vertically, horizontally or as a grid - locally.

Open tool

Design

Color Converter (HEX / RGB / HSL / OKLCH)

Convert colors between HEX, RGB, HSL and OKLCH. WCAG contrast.

Open tool