Online Tools & Utilities
Free, fast, and easy-to-use web tools for everyone. Streamline your workflow with our comprehensive suite of 182+ utilities.
Try these first — permeability, salinity, molarity, JWT, text-to-speech and more
🎉 Major Milestone Achieved!
We've reached an incredible milestone with our growing collection of developer tools
From simple text tools to advanced scientific converters, we've got everything you need
Building a Production CLI Tool with Node.js
Ship a production-ready CLI in days, not weeks.
Master the art of building professional command-line tools. From scaffolding to publishing—learn best practices, testing, and deployment strategies used in production.
- Production-ready patterns
- Testing, CI, and npm publish
- Real-world examples
Find the Perfect Tool
Search through our collection of tools or browse by category to find exactly what you need
From the makers
Our products
SaaS tools and books we build alongside Rapid Tools Online — same quality bar, built for real workflows.
SuperApps
Build custom internal apps with tables, calendar, gallery, and more—no code required. Streamline ops and data in one place.
Explore SuperAppsWateronix
Water delivery management for large RO plants in Pakistan: routes, billing, drivers, and reporting—built for serious operations, not chat threads.
See WateronixProduction CLI with Node.js (PDF)
Also in our catalog: ship a production-ready command-line tool—from scaffolding to tests and publish. Same guide promoted site-wide; grab it here too.
View on GumroadPopular Tools
Most used converters and utilities — free, instant, no sign-up
✨ New Tools
12 new toolsCORS Preflight Explainer
Educational: from HTTP method and request headers, see if a cross-origin request would likely trigger a CORS preflight. No server calls.
Chmod Calculator
Convert octal chmod modes to rwx permission strings, binary triplets, and ls-style output. Copy chmod commands with setuid, setgid, and sticky. Client-side only.
SRI Generator
Generate Subresource Integrity hashes for script and link tags from a URL or file upload. SHA-256 and SHA-384.
CSP Helper
Parse Content-Security-Policy values, explain directives, flag common weak patterns, and copy an advisory stricter draft.
Structured Log Viewer
Paste NDJSON or logs with embedded JSON. Filter by level, search, expand objects, and copy. Client-side only.
Flow Rate Converter
Convert between flow rate units including L/s, m³/h, gal/min, cfm, and more. Perfect for HVAC, plumbing, chemical engineering, and irrigation applications
Photon Energy Converter
Convert between photon energy units including eV, nm, Hz, and joules. Essential for optics, spectroscopy, and quantum physics.
User-Agent Parser
Parse browser, OS, and device from any User-Agent string. Debugging, analytics, and support.
Hardness Scale Converter
Convert between different hardness scales including Mohs, Rockwell, Vickers, and Brinell. Essential for materials science, metallurgy, and quality control.
HTTP Status Code Lookup
Look up HTTP status codes by number or name—see meanings, usage, and copy codes instantly
Coordinate Converter
Convert between coordinate systems including decimal degrees, DMS, UTM, and MGRS. Essential for GPS navigation, surveying, mapping, and military applications.
YAML Formatter and Validator
Format and validate YAML with consistent indentation. No conversion to JSON.
Recently Updated
12 updatedHash Generator
Generate MD5, SHA1, SHA256, and SHA512 from text or file upload. File hash, checksum from file, verify file integrity. Client-side only.
Calendar
Manage and view events by day, week, or month in a smart calendar interface
Budget Planner
Take control of your finances with comprehensive budget planning. Track income, expenses, set budgets, and achieve financial goals with detailed analytics
Invoice Generator
Create professional invoices with client details, line items, taxes, discounts, and totals. Perfect for freelancers and small businesses
Quote & Estimate Builder
Build clear quotes and estimates with itemized services, optional add-ons, and built-in totals for faster approvals
Expense Tracker
Track daily business expenses by category, add notes, and export summaries for bookkeeping and tax prep
Appointment Scheduler
Create simple appointment schedules, available time slots, and customer bookings
Percentage Calculator
Calculate percentages, percentage increase/decrease, find percentage of a number, and solve percentage problems with step-by-step solutions
Average Calculator
Calculate mean, median, mode, range, standard deviation, and variance with step-by-step calculations and data visualization
Percent Error Calculator
Calculate percent error between experimental and theoretical values
Weighted Average Calculator
Calculate weighted averages where different values have different importance or weights
UUID Generator
Generate RFC 4122 compliant UUIDs (v1 and v4) with multiple output formats for databases, APIs, and applications
Latest Articles
Read our latest insights on web development, programming tips, and industry best practices.