Free Online Developer Tools

Free, fast, privacy-friendly online tools for developers: JSON formatter, converters, timestamp utilities, and more. All processing happens in your browser.

100% local, no upload, no tracking

JSON

JSON Formatter

Format, beautify, and validate JSON online. Free, fast, and 100% local — your data never leaves your browser.

Converters

JSON → TypeScript

Convert JSON to TypeScript interfaces instantly. Generate strongly-typed TS types from any JSON sample.

JSON → Go

Convert JSON to Go structs online. Generates idiomatic Go structs with proper json tags and PascalCase field names.

JSON → YAML

Convert JSON to YAML online. Preserve structure, comments-free, and ready to paste into Kubernetes or CI configs.

YAML → JSON

Convert YAML documents to JSON online. Supports YAML 1.2, multi-document streams, and produces pretty-printed JSON output.

JSON → CSV

Convert an array of JSON objects to CSV online. Headers are inferred automatically from all keys across records.

CSV → JSON

Convert CSV data to a JSON array of objects online. Auto-detects delimiter and quotes, preserves numeric types when requested.

Number Base

Convert numbers between binary, octal, decimal, and hexadecimal. Supports arbitrarily large integers using BigInt.

Encoding

Base64

Encode and decode Base64 strings online. Supports UTF-8 text and URL-safe Base64. All processing runs locally in your browser.

HTML Encode/Decode

Encode and decode HTML entities (&, <, >, ", numeric references). Useful for sanitizing user content or debugging escaped markup.

Security

JWT Decoder

Decode JSON Web Tokens (JWT) to inspect the header, payload, and signature. Runs entirely in your browser — tokens are never sent to any server.

Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes of any text online. All hashing happens in your browser using the Web Crypto API.

Web

URL Encode/Decode

Percent-encode and decode URLs online. Handles query strings, path segments, and special characters correctly.

Color Converter

Convert colors between HEX, RGB, HSL, and HSV instantly. Includes a live color preview and copy-ready CSS strings.

Generators

UUID Generator

Generate random UUIDs (v4) and time-ordered UUIDs (v7) online. Bulk generate up to 1000 at once and copy with one click.

Lorem Ipsum

Generate placeholder Lorem Ipsum text by words, sentences, or paragraphs. Perfect for mockups, wireframes, and design drafts.

Password Generator

Generate strong, random passwords with customizable length and character sets. All generation happens locally in your browser.

QR Code

Generate QR codes online for URLs, text, WiFi credentials, and more. Download as PNG or SVG. Everything runs locally.

Time & Date

Timestamp Converter

Convert Unix timestamps to human-readable dates and vice versa. Supports seconds, milliseconds, ISO 8601, and timezone selection.