Dev Utilities

Developer utilities are the Swiss army knife of your daily workflow. From testing regular expressions with real-time matching to comparing text diffs, counting words, converting letter cases, sorting lines, parsing cron expressions, and looking up HTTP status codes — these are the tools you reach for dozens of times a day.

Why Use These Tools?

These utilities address the small but frequent tasks that slow down your workflow. Instead of writing a quick script to sort lines, test a regex, or check what HTTP 422 means, you can use a purpose-built tool that gives you instant, visual results. The time savings compound quickly over a typical development day.

All dev utilities on Devkitr are completely free and run 100% in your browser. Your data never leaves your device — there are no server-side requests, no data logging, and no sign-up required.

Best Practices

• Test regex patterns with multiple edge-case inputs before using them in production code
• Use diff tools during code reviews to clearly visualize what changed between versions
• Validate cron expressions with a parser before deploying scheduled jobs to avoid timing errors
• Learn HTTP status code ranges (2xx success, 3xx redirect, 4xx client error, 5xx server error) for faster debugging

Privacy & Security

Every tool in this category processes your data entirely in your browser using JavaScript. We never transmit, store, or log any data you input. You can verify this by opening your browser's Developer Tools and monitoring the Network tab while using any tool — you'll see zero data requests related to your input.

Available Tools

• Regex Tester – Free online regex tester — test and debug regular expressions with real-time matching, highlighting, and capture group display. Alternative to RegExr.
• Text Diff Checker – Free online diff checker — compare text online side-by-side and highlight every difference. Fast text compare tool and DiffChecker alternative.
• Word & Character Counter – Count words, characters, sentences, paragraphs, and estimate reading time.
• Case Converter – Convert text between uppercase, lowercase, title case, camelCase, snake_case, and more.
• Line Sorter & Deduplicator – Sort lines alphabetically, reverse order, remove duplicates, and trim blank lines.
• Cron Expression Parser – Free cron expression parser and crontab guru — parse cron expressions into human-readable schedules with next run times. Supports Quartz and standard cron.
• HTTP Status Codes Reference – Complete HTTP status codes reference — search all HTTP response codes (1xx–5xx) with descriptions, meanings, and usage guides for every status code.
• String Escape / Unescape – Escape and unescape strings online for JSON, HTML, URLs, and regex.
• Chmod Calculator – Calculate Unix file permissions — convert between rwx notation and numeric (octal) mode.
• Aspect Ratio Calculator – Free online aspect ratio calculator — calculate image and screen aspect ratios, convert resolutions, and resize dimensions while keeping the correct ratio.
• Code Diff Viewer – Free online diff checker and code compare tool — compare text and code side-by-side with syntax highlighting, inline change markers, and difference detection.
• JavaScript Validator – JavaScript checker — check JavaScript code for syntax errors with detailed reporting.
• CSS Validator – Free online CSS validator and checker — validate CSS syntax, catch errors, and lint your stylesheets instantly with detailed error reporting.
• PHP Serializer/Deserializer – Serialize and deserialize PHP data format strings.
• IP Subnet Calculator – Calculate IP subnets, CIDR ranges, network addresses, and host counts.
• Open Graph Preview – Preview how your URL will appear when shared on social media platforms.
• Cron Job Visualizer – Free cron expression generator, translator, and visual timeline — see exactly when your cron job fires over days and weeks. Alternative to crontab guru.