The average developer's bookmark bar is littered with online tools accumulated over years: a Base64 decoder from 2018, a color picker someone shared in a Slack thread, a JSON formatter that may or may not still work. Most of these tools were built as quick utility wrappers, upload your data to a server, and may track what you paste into them. We built every tool on this site with a different philosophy: everything runs in your browser, nothing is transmitted to any server, and there is no account required. This article is a complete reference to all 21 tools and games available, what each one is for, and when to reach for it.
Encoding and Decoding Tools
Base64 Encoder / Decoder — Encodes binary or text data to Base64 and decodes it back. Supports standard and URL-safe alphabets. Use this when inspecting JWT tokens (decode the header and payload to see their contents), when debugging HTTP Basic Auth headers, when examining data URI values embedded in CSS or HTML, or when an API returns Base64-encoded content that you need to read. The URL-safe variant replaces + with - and / with _ for safe use in query strings and filenames.
URL Encoder / Decoder — Encodes special characters in URL components using percent-encoding and decodes percent-encoded strings back to readable text. Use this when constructing API calls with query parameters containing special characters, when debugging a URL that appears to have incorrect encoding, when building redirect URIs for OAuth flows, or when working with internationalized URLs that contain non-ASCII characters. The tool encodes using encodeURIComponent() semantics, which is safe for encoding values that will be inserted into query strings or path segments.
Code and Data Tools
JSON Formatter and Validator — Validates JSON syntax, reports errors with exact line numbers, formats with configurable indentation, and minifies. Use this when debugging API responses, when working with configuration files, when preparing JSON for documentation, or when you need to quickly inspect a large JSON blob. The validator catches the most common JSON mistakes: trailing commas, single-quoted strings, unescaped control characters, and mismatched brackets.
Hash Generator — Computes SHA-256, SHA-512, SHA-1, and MD5 hashes of any text input using the browser's native Web Crypto API. Use this when verifying file checksums, when debugging HMAC implementations, when generating content fingerprints, or when teaching cryptography concepts interactively. Note that MD5 and SHA-1 are computed for compatibility and education purposes — neither should be used in new security-sensitive implementations.
UUID v4 Generator — Generates cryptographically secure UUID v4 identifiers using crypto.randomUUID(). Produces up to 100 at a time. Use this when populating test fixtures, seeding development databases, generating batch API request IDs, creating idempotency keys for retryable operations, or any scenario requiring multiple unique identifiers. All generated UUIDs use the browser's CSPRNG and are suitable for security-sensitive contexts.
Markdown Previewer — Renders GitHub Flavored Markdown in real time in a split-pane view. Use this when drafting README files, writing documentation, composing technical blog posts in Markdown, or learning Markdown syntax interactively. Supports tables, task lists, fenced code blocks, and all standard GFM features. Rendering happens locally with marked.js — no content is transmitted.
Text and Content Tools
Case Converter — Converts text between camelCase, PascalCase, snake_case, SCREAMING_SNAKE_CASE, kebab-case, Title Case, and more. Use this when working across language boundaries where naming conventions differ, when normalising identifiers from an API response into a format suitable for your codebase, when batch-converting database column names to code variable names, or when refactoring inconsistent legacy code identifiers.
Word Counter — Counts words, characters (with and without spaces), sentences, paragraphs, and estimated reading time. Use this when checking content length for SEO, when verifying that content meets platform character limits (meta descriptions, Twitter, SMS), when estimating reading time for newsletter content, or when ensuring academic writing meets minimum word requirements.
URL Slug Generator — Converts any title or phrase into a clean, SEO-friendly URL slug. Handles Unicode characters, strips special characters, converts spaces to hyphens, and applies consistent lowercase normalisation. Use this when creating new blog post or product page URLs, when migrating content from a CMS that used poor URL conventions, or when building a slug generation function and want to verify your implementation against expected output.
Visual and Media Tools
QR Code Generator — Generates QR codes that use a transparent redirect page, ensuring users see the destination before arriving. Use this for marketing campaigns, product packaging, event signage, contact sharing, and any printed material where you want to provide a scannable link. The transparent redirect approach builds user trust and reduces accidental navigation to unexpected destinations.
Color Picker and Converter — Pick any color visually and instantly see the equivalent values in HEX, RGB, HSL, and HSV. Use this during design-to-code handoff when a designer provides a color in one format and your CSS uses another, when building a design system and needing consistent color representations across tokens, or when debugging why a color appears different between a design file and a browser render.
Image Converter — Converts images between JPG, PNG, and WebP entirely in the browser using the Canvas API. Use this when a platform accepts only a specific format, when optimising images for web performance (converting large PNGs to WebP), or when you need to quickly change format without installing image editing software. The conversion is immediate and private — images are never uploaded.
Image to PDF — Converts one or multiple images into a single PDF document, with images laid out as sequential pages. Use this when document submission portals accept only PDFs, when archiving image-based records, when preparing multi-page scanned documents for sharing, or when building a portable version of image assets for distribution.
Security and Generation Tools
Password Generator — Generates cryptographically strong passwords using window.crypto.getRandomValues(). Configurable length (up to 128 characters), character sets, and real-time entropy display. Nothing is stored or transmitted. Use this for generating service account passwords, database credentials, encryption keys in non-critical personal use cases, and any scenario requiring a strong random password that will not be remembered by a human.
Timestamp Converter — Converts between Unix timestamps (seconds and milliseconds) and human-readable ISO 8601 dates in both directions, with millisecond precision. Use this when reading log events, debugging API responses that return Unix timestamps, converting between epoch time and calendar dates for database queries, or verifying that a timestamp corresponds to the expected date and time.
Browser Games
Six browser games are available at our Games Hub: Tic Tac Toe (two-player or vs. computer AI, best of three rounds), Snake (classic growing-snake arcade with progressive speed), Memory Match (flip cards to find pairs, timed and move-counted), 2048 (merge tiles to reach the 2048 tile), Breakout (paddle-and-ball brick-breaking), and Tetris (classic falling-block puzzle). All games run entirely in the browser with no installation, no accounts, and no ads inside the game interface.
All 21 tools and games share a design principle: your data stays with you. No file uploads, no user accounts, no telemetry, no advertising trackers. Every operation happens locally using Web APIs built into your browser. This is not just a privacy feature — it also means the tools work offline (after the initial page load) and produce no latency from network round trips. Bookmark the ones relevant to your workflow and reach for them whenever you need a quick, reliable, private utility.