What does a JSON formatter/validator do, and why should I minify JSON?

A JSON formatter checks your JSON for syntax errors and re-indents it so it's easy to read, highlighting exactly where a missing comma or bracket breaks parsing. A validator tells you whether a payload is valid before you send it to an API or commit it to a config file. Minifying does the opposite — it strips whitespace and line breaks to produce the smallest possible JSON, which is useful when you're shipping payloads over the wire and every byte counts.

How do I test a regular expression safely?

Start with short, synthetic text. Both actions use the same flags in a dedicated worker that is terminated after one second, keeping expensive matching off the page thread. The details list positions, numbered captures, and named groups; output is capped at 1,000 matches. JavaScript syntax and Unicode behavior follow the browser. Simplify timed-out patterns instead of assuming a timeout means no match.

What is a JWT, and is it safe to decode one in a browser tool?

A readable three-part JWT contains a Base64URL JSON header and payload plus a signature segment; unsigned variants also exist. The decoder processes those JSON objects locally, but does not verify signatures or establish trust. Expiry status describes an unverified claim only. Use synthetic or redacted examples, not production credentials, and consider device, clipboard, and optional-provider exposure separately.

How do I write a cron expression?

A cron expression is a five-field string (minute, hour, day of month, month, day of week) that schedules recurring jobs on Unix systems — for example, '0 9 * * 1' runs every Monday at 9:00 AM. The Cron Job Maker takes the guesswork out: pick a preset like 'every hour' or fill in the fields, and it validates the expression and explains the schedule in plain words. That's the fastest way to learn the syntax, since the plain-language description immediately shows whether your expression does what you intended.

When should I use YAML vs JSON?

JSON is common for API data; YAML is common for human-edited configuration and comments. They are not interchangeable without limits: JSON conversion drops YAML comments and cannot represent every YAML type or cyclic alias. Keep the original configuration, inspect conversion errors, and check the resulting types before using a converted file.

Do these developer tools upload my code anywhere?

Many core transformations, including JSON formatting, Base64 conversion, and JWT decoding, process locally. Remote previews and website or network checks need requests to SiteIndex endpoints or external services. Optional analytics and ads are separately consent-gated; tool workspaces are marked for Clarity masking, not guaranteed confidentiality. Public targets and diagnostic errors may be logged. Avoid secrets, and do not assume every feature works offline.

Developer Tools

Format, encode, test, hash, convert, and inspect data for development workflows. Pick a tool below to open it.

51 Tools

Developer

Format, encode, test, hash, convert, and inspect data for development workflows.

51 tools

Developer Toolkit OverviewReview the most-used developer utilities for JSON, YAML, CSV, regex, timestamps, and build-time helpers in one dashboard.JSON FormatterValidate, format, minify, copy, and download JSON with a quick browser-based parser.Base64Encode and decode UTF-8 text directly in your browser.Hash GeneratorCreate MD5, SHA-1, SHA-256, SHA-384, or SHA-512 checksums locally in your browser, and compare text digests with a published value.Number Base ConverterConvert non-negative integers between binary, decimal, and hexadecimal.JWT DecoderDecode readable JWT headers and payloads locally without verifying signatures.URL EncoderEncode or decode URL strings and query parameter content securely in-browser.UUID GeneratorGenerate version 4 UUID strings using cryptographically secure randomness.Timestamp ConverterConvert between Unix timestamps and human-readable dates in seconds or milliseconds.Regex TesterTest regular expressions against sample text to validate search and parse logic quickly.Cron Job MakerGenerate cron expressions with presets, validation, and human-friendly explanations for common Linux and Unix schedules.YAML to JSONConvert YAML into JSON with validation and instant browser-side output for API and config workflows.JSON to YAMLTransform JSON into YAML for configuration files, deployments, and readable structured data.CSV to JSONParse CSV data into structured JSON arrays and objects for quick app, API, and spreadsheet workflows.JSON to CSVConvert JSON arrays into CSV tables for easy import into spreadsheets and data tools.XML FormatterPretty-print and validate XML with readable indentation, cleanup, and error feedback.SQL FormatterFormat SQL statements with indentation, consistent spacing, and readable database query output.Text DiffCompare two text blocks and highlight the exact additions, removals, and changes between versions.URL ParserBreak down a URL into protocol, host, path, query parameters, hash, and other useful components.HTML Escape / UnescapeEscape HTML special characters into entities or unescape entities back into raw HTML text.ASCII / HEX ConverterConvert text to its hexadecimal byte representation, or decode hex back into readable ASCII text.CSP Header ParserBreak a Content-Security-Policy header into its individual directives and sources for review.CSS Gradient GeneratorBuild linear and radial CSS gradients visually and copy the generated background or text gradient code.Box Shadow GeneratorDesign layered CSS box shadows with a live preview and copy the generated box-shadow declaration.Border Radius GeneratorAdjust each corner radius independently and copy the resulting CSS border-radius declaration.Color Contrast CheckerCheck the contrast ratio between two colors against WCAG AA and AAA accessibility thresholds.OGP Tag GeneratorGenerate Open Graph and Twitter/X meta tags from a title, description, image, and URL.OGP Image SimulatorPreview how a title, description, and image will look as a shared social link card.SVG OptimizerOptimize an SVG in your browser with SVGO, preview its markup, compare file sizes, and download the optimized vector.Subnet CalculatorCalculate an IPv4 subnet's network, broadcast, mask, host range, usable host count, and binary representation locally in your browser.Schema Markup GeneratorGenerate JSON-LD for FAQ, HowTo, Article, LocalBusiness, Product, and Breadcrumb schemas. Structured data stays in your browser.UTM BuilderBuild a campaign URL with source, medium, campaign, term, and content parameters, plus presets and URL validation. Data stays in your browser.SERP PreviewPreview a search result title, description, and URL with desktop and mobile layouts, and measure text pixel widths in your browser.Robots.txt GeneratorBuild a robots.txt file with user-agent, allow, disallow, crawl-delay, and sitemap rules, then download it locally.XML Sitemap GeneratorTurn a pasted list of absolute URLs into XML sitemap entries with optional last-modified dates, change frequency, and priority.TOTP GeneratorGenerate rolling six-digit authenticator codes from a Base32 shared secret using Web Crypto. Secret processing is fully client-side.SSH Key GeneratorGenerate an RSA 2048-bit or ECDSA P-256 SSH key pair in your browser with an OpenSSH public key and PKCS#8 PEM private key.CSR DecoderDecode common subject fields and public-key and signature algorithms from a PEM certificate signing request in your browser.File Hash CheckerCalculate MD5, SHA-1, SHA-256, and SHA-512 digests for local files using browser APIs and a local MD5 implementation. Files are not uploaded.WebSocket TesterConnect to a WebSocket endpoint you choose, send messages, and inspect live events in a browser log. Messages go only to that endpoint.Meta Tag GeneratorCreate escaped page title, description, canonical, robots, viewport, and optional author tags.CSS Button GeneratorStyle a button with live colors, spacing, corners, hover, and keyboard focus, then copy CSS and HTML.XML to JSON ConverterConvert XML to an ordered JSON representation retaining attributes, mixed content, and repeated elements.cURL to Code ConverterConvert a cURL request into Python requests, JavaScript fetch, and PHP cURL examples in your browser.JWT SignerSign JSON claims as a JWT with HMAC or an RS256 private key using browser cryptography.OpenAPI ViewerInspect API operations and paths from an OpenAPI or Swagger document in JSON or YAML..gitignore GeneratorGenerate a starter .gitignore file from common Node, Python, Java, Go, and React presets.CSS Specificity CalculatorEstimate the ID, class, attribute, pseudo-class, and element specificity of a CSS selector.Code Screenshot GeneratorPreview a code snippet and download it as a PNG image rendered in your browser.README GeneratorDraft a project README with a title, description, setup steps, usage section, and SPDX license reference.License Notice GeneratorCreate an SPDX license notice for a project using common license identifiers.

Choose a tool for the data you have

Use formatters to inspect structured text, converters to move supported data between formats, and generators to create development fixtures. The Developer Toolkit Overview links focused workspaces; it does not run a pipeline automatically. Browser interfaces do not imply browser-only processing: remote previews and network checks may contact SiteIndex endpoints or public services.

Build a small, reviewable workflow

Validate JSON before converting object rows to CSV. Preserve your original YAML because JSON cannot retain comments or every YAML type. Choose an explicit timestamp unit and cron timezone before interpreting dates. JWT decoding reads claims, not signatures or authorization. Review each tool's errors and limitations rather than assuming a formatted result is semantically correct.

Use synthetic input and verify outputs

Core formatting and encoding can happen locally, while requested remote resources and optional consented providers follow different data paths. Do not paste production credentials or confidential payloads. Copy between tools explicitly and check the target system's requirements. The guides explain what JSON is and how HTTP status codes work when you need background rather than another conversion.

Frequently asked questions

What does a JSON formatter/validator do, and why should I minify JSON?: A JSON formatter checks your JSON for syntax errors and re-indents it so it's easy to read, highlighting exactly where a missing comma or bracket breaks parsing. A validator tells you whether a payload is valid before you send it to an API or commit it to a config file. Minifying does the opposite — it strips whitespace and line breaks to produce the smallest possible JSON, which is useful when you're shipping payloads over the wire and every byte counts.
How do I test a regular expression safely?: Start with short, synthetic text. Both actions use the same flags in a dedicated worker that is terminated after one second, keeping expensive matching off the page thread. The details list positions, numbered captures, and named groups; output is capped at 1,000 matches. JavaScript syntax and Unicode behavior follow the browser. Simplify timed-out patterns instead of assuming a timeout means no match.
What is a JWT, and is it safe to decode one in a browser tool?: A readable three-part JWT contains a Base64URL JSON header and payload plus a signature segment; unsigned variants also exist. The decoder processes those JSON objects locally, but does not verify signatures or establish trust. Expiry status describes an unverified claim only. Use synthetic or redacted examples, not production credentials, and consider device, clipboard, and optional-provider exposure separately.
How do I write a cron expression?: A cron expression is a five-field string (minute, hour, day of month, month, day of week) that schedules recurring jobs on Unix systems — for example, '0 9 * * 1' runs every Monday at 9:00 AM. The Cron Job Maker takes the guesswork out: pick a preset like 'every hour' or fill in the fields, and it validates the expression and explains the schedule in plain words. That's the fastest way to learn the syntax, since the plain-language description immediately shows whether your expression does what you intended.
When should I use YAML vs JSON?: JSON is common for API data; YAML is common for human-edited configuration and comments. They are not interchangeable without limits: JSON conversion drops YAML comments and cannot represent every YAML type or cyclic alias. Keep the original configuration, inspect conversion errors, and check the resulting types before using a converted file.
Do these developer tools upload my code anywhere?: Many core transformations, including JSON formatting, Base64 conversion, and JWT decoding, process locally. Remote previews and website or network checks need requests to SiteIndex endpoints or external services. Optional analytics and ads are separately consent-gated; tool workspaces are marked for Clarity masking, not guaranteed confidentiality. Public targets and diagnostic errors may be logged. Avoid secrets, and do not assume every feature works offline.