About DeveloperKit

Developers paste sensitive data into online tools every day: API responses, configuration files, logs, and tokens. Many of these tools send that data to a server. We think that is unnecessary. Formatting, validating, and comparing data can happen right where the data already is: on your device.

Our goal is to offer the tools you reach for every day, with a clean interface, precise error messages, and no compromises on privacy.

• 100% client-side. Every tool runs in your browser. Your data is never uploaded, stored, or shared.
• Fast by default. Pages load quickly and tools respond instantly, even with large inputs.
• Precise feedback. When something is wrong, we tell you exactly where and why, down to the line and column.
• Free to use. No sign-up and no paywalls.

• JSON Formatter: Beautify, minify, and validate JSON instantly with exact line and column error reporting.
• JSON Comparer: Compare two JSON documents side by side and see every added, removed, and changed value.
• JSON to XML: Convert JSON to well-formed XML with custom root and item names, attributes, and indentation.
• JSON to CSV: Turn JSON arrays into CSV for Excel or Google Sheets, with nested object flattening and custom delimiters.
• JSON to YAML: Convert JSON to clean, readable YAML for Kubernetes, Docker Compose, CI pipelines, and config files.
• JSON to Base64: Encode JSON as Base64 or base64url for headers, tokens, environment variables, and data URIs.
• Base64 to JSON: Decode Base64 or base64url back into readable, validated, and pretty-printed JSON.
• XML Formatter: Beautify, minify, and validate XML with exact line and column errors for unclosed tags, bad entities, and more.
• XML Comparer: Compare two XML documents side by side and see every changed element, attribute, and value.
• XML to JSON: Convert XML to JSON with attributes, repeated elements as arrays, and automatic number and boolean detection.
• XML to YAML: Convert XML documents and configs into clean, readable YAML.
• XML to CSV: Turn repeated XML records into a CSV table for Excel or Google Sheets, with automatic row detection.
• XML to Base64: Encode XML documents, SOAP messages, and SVG as Base64 or base64url.
• Base64 to XML: Decode Base64 into well-formed, validated, and formatted XML.
• YAML Formatter: Format and validate YAML with exact line and column errors. Keeps comments, anchors, and block scalars.
• YAML to Base64: Encode YAML as Base64 for Kubernetes Secrets, CI variables, and config values.
• Base64 to YAML: Decode Base64 strings, such as Kubernetes Secret values, back into readable YAML.
• HTML Formatter: Beautify or minify HTML and find unclosed tags, stray closing tags, and duplicate attributes.
• HTML Viewer: Preview HTML live in a secure sandbox with mobile and tablet widths. Scripts and network access are off by default.
• SQL Formatter: Beautify long one-line SQL queries and ORM logs into clean, indented, syntax-highlighted SQL, or minify them.
• GraphQL Formatter: Format and validate GraphQL queries, mutations, fragments, and schemas (SDL) with syntax highlighting.
• Markdown Editor & Previewer: Write Markdown with a live GitHub-style preview: tables, task lists, code blocks, and alerts. Ideal for README files.
• JWT Decoder: Decode and debug JSON Web Tokens, see when they expire, and verify HS, RS, PS, ES, and EdDSA signatures.
• JWT Encoder: Create and sign JSON Web Tokens with HS256, RS256, ES256, PS256, or EdDSA, and generate test key pairs.
• Hash Generator: Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes and HMACs of text or files, live as you type.
• Bcrypt Generator: Hash passwords with bcrypt at any cost factor and verify a password against an existing bcrypt hash.
• UUID Generator: Generate v4, v7, v1, v5, and v3 UUIDs / GUIDs in bulk, and inspect any UUID's version and timestamp.
• Password Generator: Generate strong random passwords and memorable passphrases with the browser's secure random generator.
• RSA Key Pair Generator: Generate 2048, 3072, or 4096-bit RSA key pairs as PEM (PKCS#8, PKCS#1), JWK, or OpenSSH, in your browser.
• Text Diff Checker: Compare two texts or code snippets side by side, with changed words highlighted and a downloadable patch.
• Regex Tester: Test JavaScript regular expressions live, with highlighted matches, capture groups, and find and replace.
• String Case Converter: Convert text and variable names to camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, and more.
• Word, Character & Byte Counter: Count words, characters, sentences, lines, and UTF-8 bytes as you type, with reading time and length limits.
• Lorem Ipsum Generator: Generate lorem ipsum placeholder text by paragraphs, sentences, or words, as plain text, HTML, or Markdown.
• Fake Data Generator: Generate realistic fake names, emails, addresses, and products in bulk as JSON, CSV, or SQL for testing.
• QR Code Generator: Turn a URL, text, or Wi-Fi network into a QR code instantly and download it as SVG or PNG.
• Cron Expression Generator: Build cron schedules with dropdowns, translate expressions like */15 * * * * into plain English, and see the next run times.
• URL Encoder / Decoder: Percent-encode or decode URLs and query values, and unwrap double-encoded strings from logs in one click.
• URL Parser: Break a URL into protocol, host, port, path, and fragment, and edit its query parameters as a key-value table.
• User-Agent Parser: Identify the browser, operating system, device type, and bots from any User-Agent string, one or thousands at once.
• cURL to Fetch / Axios: Convert cURL commands, including Copy as cURL from DevTools, into JavaScript fetch() or axios code.
• HTTP Status Codes: Search every HTTP status code, from 200 OK and 404 Not Found to 418 I'm a teapot, with causes and fixes.
• Unix Timestamp Converter: Convert Unix epoch timestamps in seconds, milliseconds, or nanoseconds to dates in any time zone, and dates back to timestamps.
• Time Zone Converter: Compare the time in UTC and cities around the world side by side, with a 24-hour timeline and daylight saving info.
• Number Base Converter: Convert numbers between binary, octal, decimal, and hexadecimal instantly, with two's complement and a bit editor.
• Color Converter: Convert any color between HEX, RGB, HSL, HWB, OKLCH, Lab, and CMYK, with shades, tints, and color harmonies.
• Color Contrast Checker: Check text and background colors against WCAG AA and AAA contrast rules, preview them, and get passing alternatives.
• SVG Optimizer: Shrink SVG files by removing Figma, Illustrator, and Inkscape leftovers, rounding numbers, and minifying path data.

You can read exactly what we do and do not collect in our Privacy Policy.