What to look for

• Privacy: client-side processing so tokens, keys and payloads are never uploaded.
• No install or sign-up for everyday utilities.
• Breadth: one place for JSON, JWT, regex, diff, encoding, HTTP, images and databases.
• Speed and quality: editor-grade UX (syntax highlighting, copy buttons, shareable state).

Popular tools and DevStudio Online equivalents

Core tools

• Diff Checker — Side-by-side code and text comparison with syntax highlighting for 10+ languages.
• JSON Beautifier — Format, minify and validate JSON in split editors.
• JWT Tools — Decode, verify and generate JSON Web Tokens.
• Encoder / Decoder — Base64 and URL encode/decode in the browser.
• Encrypt / Decrypt — AES-256, SHA/MD5 hashing, HMAC and classic ciphers.
• JS Playground — Run JavaScript in a sandboxed editor with console output and shareable links.
• Lat/Long Picker — Pick GPS coordinates on Google Maps; DD/DMS formats.
• Image Editor — Crop, resize, rotate, filter and convert images.
• PDF Editor & Merger — Merge, compress and extract text from PDFs.
• Webhook Tester — Real-time webhook endpoint to inspect incoming requests.
• Temp Mail — Disposable email inbox.
• MySQL Connector — Schema browser and SQL editor for MySQL.
• PostgreSQL Connector — Schema browser and SQL editor for PostgreSQL.
• Email Tool — SMTP sender with templates and mailing lists.
• SSH Manager — Browser SSH terminal and SFTP file manager.

Converters

Convert between JSON, CSV, YAML, XML, timestamps, and more

• Timestamp Converter — Convert Unix timestamps to readable dates and back, in seconds or milliseconds.
• cURL Converter — Convert cURL commands to JavaScript fetch, Axios, Python requests, and PHP code.
• JSON to CSV — Convert JSON arrays to CSV, flattening nested objects into columns.
• CSV to JSON — Convert CSV to JSON with header detection, number and boolean typing, and delimiter auto-detect.
• JSON to YAML — Turn JSON into clean, human-readable YAML for config files.
• YAML to JSON — Parse YAML config files into valid JSON, including multi-document files and merge keys.
• JSON to XML — Convert JSON to well-formed XML with a custom root element.
• XML to JSON — Convert XML documents to JSON, keeping attributes and detecting numbers and booleans.

Formatters

Format, validate, and minify code and data

• XML Formatter — Beautify, validate, and minify XML documents.
• SQL Formatter — Format and minify SQL for MySQL, PostgreSQL, SQL Server, SQLite, and more.
• Code Minifier — Minify JavaScript, CSS, and HTML to cut file size.

Text Tools

Count, convert, and clean up text

• Case Converter — Convert text to UPPER, lower, Title, camelCase, snake_case, kebab-case, and more.
• Word Counter — Count words, characters, sentences, and paragraphs, with reading time and keyword density.
• Slug Generator — Turn titles into clean, SEO-friendly URL slugs with custom separators and stop-word removal.

Generators

Generate test data, passwords, IDs, QR codes, and CSS

• CSS Box Shadow Generator — Visually build layered CSS box shadows and glassmorphism effects, then copy the CSS.
• Mock JSON Generator — Generate realistic mock JSON for API testing and prototypes — up to 1,000 objects.
• Dummy Data Generator — Generate dummy test data as CSV, JSON, or SQL INSERTs — up to 1,000 rows.

Image Tools

Convert, resize, and compress images right in your browser

• Image Converter — Convert images between PNG, JPG, and WebP — batch, in your browser.
• Image Resizer — Resize images by pixels or percentage — batch, with aspect ratio lock.
• Image Compressor — Compress JPG, PNG, and WebP images in bulk and see exactly how much you save.
• Favicon Generator — Turn any image into a full favicon set: .ico, PNG sizes, Apple touch icon, and web manifest.
• Image to PDF — Combine up to 20 images into one PDF — reorder pages, pick page size and margins.
• SVG Resizer — Resize SVG width and height without cropping, then export SVG or PNG.

Web & SEO

Meta tags, robots.txt, schema markup, and server config helpers

• MIME Type Lookup — Find the correct MIME type for any file extension, and the extensions for any MIME type.
• Open Graph Generator — Generate Open Graph and Twitter Card meta tags for rich link previews.
• Robots.txt Generator — Build a robots.txt with crawler rules, sitemaps, and presets like blocking AI bots.
• .htaccess Generator — Generate Apache .htaccess rules: HTTPS and www redirects, caching, gzip, security headers.
• Schema Markup Validator — Validate JSON-LD structured data against required and recommended schema.org properties.
• Text-to-HTML Ratio — Measure the text-to-HTML ratio of a page and spot bloated markup that hurts SEO.

Network

DNS, IP, HTTP, and subnet utilities

• HTTP Status Codes — Searchable reference of HTTP status codes with explanations, from 1xx to 5xx.
• CIDR Calculator — Calculate IPv4 and IPv6 subnets: network, broadcast, usable range, masks, and host counts.
• DNS Lookup — Look up A, AAAA, MX, TXT, NS, CNAME, SOA, CAA, and other DNS records over DNS-over-HTTPS.
• What Is My IP — See your public IPv4 and IPv6 address with location and ISP, or look up any IP.
• HTTP Header & Redirect Checker — Trace redirects hop by hop, inspect response headers, and grade a site's security headers.
• HTTP Request Builder — Send GET, POST, PUT, PATCH, and DELETE requests with headers, auth, and a body — like a lightweight Postman.

Security

Password hashing and certificate inspection

• Bcrypt & Argon2 Hasher — Generate and verify bcrypt and Argon2 password hashes — nothing leaves your browser.
• SSL Certificate Parser — Decode X.509 / PEM certificates: subject, issuer, validity, SANs, key usage, and fingerprints.

Editors

Code editors and live sandboxes that run in your browser

• HTML CSS JS Sandbox — Write HTML, CSS, and JavaScript with a live preview and console — like a tiny CodePen.
• Online Code Editor — Multi-tab code editor with syntax highlighting for 20 languages — auto-saved in your browser.

Utilities

Handy tools for everyday developer tasks

• Cron Expression Parser — Translate cron expressions into plain English and preview the next run times.

Frequently asked questions