# Developer Hub (DevHub) > The Everyday Client-Side Toolkit for Software Developers, DevOps Engineers, and System Architects. Developer Hub provides 19 fast, free, and privacy-preserving developer utilities. Every single transformation, cryptographic calculation, parsing, and formatting operation runs **100% locally inside the user's browser** using JavaScript and the hardware-accelerated W3C Web Crypto API. No data is ever transmitted to a backend server. - **Website**: https://developerhub.tools / https://ais-pre-xqfkrdwi4yz6upjish6vg5-189406732208.asia-southeast1.run.app/ - **Architecture**: Single Page Application (React + Vite + Tailwind CSS) - **Privacy Model**: Zero server roundtrips, no accounts, no telemetry, no persistent cloud storage. All inputs stay in memory or local storage. - **License / Cost**: Free forever ($0.00 USD) --- ## Complete Tools Catalog ### Formatters - [JSON Viewer, Formatter & Validator](/tools/json-formatter): Formats, minifies, validates, and visually inspects JSON data hierarchies with color keys and tree navigation. - [HTML Beautifier & Minifier](/tools/html-formatter): Indents and formats messy HTML, nests tags, strips comments, and provides an isolated sandboxed iframe preview. - [XML Formatter & Syntax Validator](/tools/xml-formatter): Beautifies XML documents, enforces tag closure, validates well-formedness, and converts XML to clean JSON objects. - [YAML Formatter & Linter](/tools/yaml-formatter): Formats YAML documents, validates indentation schemas, provides error diagnosis, and converts two-way between YAML and JSON. - [SQL Query Formatter](/tools/sql-formatter): Formats complex queries across ANSI SQL, PostgreSQL, MySQL, SQLite, T-SQL, and BigQuery with uppercase/lowercase keyword normalization. ### Encoders & Converters - [Base64 Encoder & Decoder](/tools/base64): Converts plain text and UTF-8 multi-byte strings to and from RFC 4648 Base64 representations with instant swap. - [URL Percent Encoder & Decoder](/tools/url-encoder): Encodes and decodes query strings and URLs using standard `encodeURIComponent` and `encodeURI` specifications. - [JSON to CSV Converter](/tools/json-to-csv): Converts JSON object arrays into structured RFC 4180 CSV files with automatic key extraction and nested object flattening. - [CSV to JSON Converter](/tools/csv-to-json): Parses delimiter-separated values (CSV, TSV, pipes) into strongly typed JSON arrays with header detection. ### Security & Tokens - [Cryptographic Hash Generator](/tools/hash-generator): Computes MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes simultaneously using the native Web Crypto API. - [JWT Decoder & Expiry Inspector](/tools/jwt-decoder): Decodes RFC 7519 JSON Web Tokens into Header, Payload, and Signature components with human-readable UNIX expiration detection. - [JWT Generator & Signer](/tools/jwt-generator): Generates and cryptographically signs custom JWT tokens using HMAC (HS256, HS384, HS512) and RSA (RS256, RS384, RS512) key pairs. ### Generators - [UUID v4 Generator](/tools/uuid-generator): Generates RFC 4122 Version 4 Universally Unique Identifiers using cryptographic entropy (`crypto.getRandomValues`). - [Cron Expression Parser](/tools/cron-parser): Translates 5-field UNIX cron schedules into plain English human sentences and calculates the next 5 upcoming run execution timestamps. ### Testing & Debugging - [Regular Expression Tester](/tools/regex-tester): Tests JavaScript regex patterns in real-time with global (`g`), case-insensitive (`i`), multiline (`m`), and dotAll (`s`) flags with capture group breakdown. - [Diff Checker & Code Comparison](/tools/diff-checker): Compares two text blocks line-by-line using Myers diff algorithm, supporting side-by-side and unified views with whitespace filtering. ### Date, Design & Documentation - [UNIX Timestamp Converter](/tools/timestamp-converter): Converts UNIX epoch timestamps (seconds and milliseconds) to ISO 8601, UTC, RFC 2822, and local timezones, plus date picker conversion. - [Color Converter & Contrast Checker](/tools/color-converter): Converts between HEX, RGB, RGBA, HSL, HSLA, HSV, and CMYK color spaces, with WCAG 2.1 AA/AAA accessibility contrast auditing. - [Markdown Editor & Live Preview](/tools/markdown-editor): Dual-pane Markdown editor with real-time HTML rendering, word count metrics, syntax cheat sheet, and 1-click HTML export. --- ## Technical Specifications & Standards Compliance - **UUIDs**: RFC 4122 v4 compliant. 122 bits of cryptographic randomness generated via `window.crypto.getRandomValues`. - **JWTs**: RFC 7519, RFC 7515 (JWS) compliant. Supported algorithms: HS256, HS384, HS512 (HMAC SHA-2) and RS256, RS384, RS512 (RSASSA-PKCS1-v1_5). - **Base64**: RFC 4648 compliant with full UTF-8 Unicode byte array support (`TextEncoder` / `TextDecoder`). - **CSV**: RFC 4180 standard quotation and comma escaping. - **Hashes**: NIST FIPS 180-4 standard SHA-256, SHA-384, SHA-512, SHA-1 and RFC 1321 MD5. - **Color Spaces**: WCAG 2.1 contrast ratio calculations, sRGB matrix transformations, and standard CSS Color Module Level 4 specifications. --- ## Frequently Asked Questions (FAQ) ### Is Developer Hub safe for enterprise data and API tokens? Yes. All processing occurs exclusively in client-side browser memory. There is no backend API server receiving your data. Network inspector inspection confirms zero outbound payload traffic. ### How does Developer Hub differ from traditional developer utilities? Most online utilities are bloated with tracking scripts, intrusive banners, and backend logging. Developer Hub is open, instant, lightweight, offline-capable, and designed specifically for professional engineers. ### Can Developer Hub run without an internet connection? Yes. Once cached by your browser, Developer Hub functions completely offline as a standalone Progressive Web App.