How-To Guides
Step-by-step guides for the most common things people want to do online — format JSON, generate a secure password, compress a photo, calculate a percentage. Every guide walks through the task and links you straight to the free tool that does it in your browser. No signup, no uploads, no tracking.
How to Format JSON Online (Free, No Signup) — 2026 Guide
Learn how to format and beautify JSON online in seconds. Paste raw JSON, get clean indented output, validate syntax — all free, in your browser, no data sent to a server.
How to Generate a Strong Password Online (Free, Secure)
Generate a cryptographically strong random password in your browser — customizable length, symbols, and exclusions. No account, no server logs, no storage.
How to Count Words Online — Free Word Counter for Essays & Articles
Count words, characters, sentences, paragraphs, and reading time in any text — free, instant, in your browser. Works for essays, articles, emails, and social posts.
How to Compress Images Online Free (JPG, PNG, WebP)
Compress JPG, PNG, and WebP images in your browser — no uploads, no watermarks, no signup. Shrink file size by 60-80% with almost no visible quality loss.
How to Generate a QR Code Online Free (No Signup)
Create a free QR code for any URL, text, or contact info in seconds. Downloads as PNG or SVG. No account, no expiration, no tracking — generated entirely in your browser.
How to Calculate Percentage Online — Every Formula Explained
Calculate percentages, percentage increase/decrease, percent of a number, and what percent X is of Y — free online calculator with worked examples of every formula.
How to Calculate BMI Online — Free BMI Calculator (Metric & Imperial)
Calculate Body Mass Index in kg/m² or lbs/ft. Understand what your BMI number means, its limits, and why athletes and children need different interpretations.
How to Calculate Age Online — Exact Years, Months, and Days
Calculate your exact age in years, months, days, hours, or minutes from any birthdate. Handles leap years correctly and supports date-to-date age comparison.
How to Calculate Mortgage Payment — Free Monthly Payment Calculator
Calculate monthly mortgage payments from loan amount, interest rate, and term. Includes PMI, property tax, and insurance estimates — plus amortization schedule.
How to Encode/Decode Base64 Online (Free, Browser-Based)
Encode strings, files, or images to Base64 and decode Base64 back to plain text — instant, client-side, no uploads. Supports UTF-8, binary, and data URIs.
How to Generate UUID Online — Free UUID v4 & v7 Generator
Generate RFC 4122 UUIDs (v4 random, v1 time-based, v7 sortable) instantly in your browser. Bulk generate hundreds at once — free, no signup, cryptographically random.
How to Convert Text Case Online — UPPERCASE, lowercase, camelCase, snake_case
Convert text between UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case, and more — instant, free, no signup. Perfect for code, headlines, and filenames.
How to Convert HEX to RGB (and RGB to HEX) Online Free
Convert between HEX (#FF5733), RGB (255, 87, 51), HSL, and CMYK color formats instantly. Paste any color value, get every representation — with alpha channel support.
How to Convert Celsius to Fahrenheit Online — Free Temperature Converter
Convert °C to °F (or Kelvin) instantly. Free temperature converter with full formula, common reference points, and reverse conversion — no ads, no signup.
How to Hash a String with SHA-256 Online (Free, Client-Side)
Generate SHA-256, SHA-1, MD5, and SHA-512 hashes in your browser. Free, instant, runs entirely client-side — no strings leave your device.
How to Test Regex Online — Free Regex Tester with Live Match Highlighting
Test regular expressions against sample text with live match highlighting, capture groups, and flag support (g, i, m, s, u). Works with JavaScript, PCRE, and POSIX flavors.
How to Minify JavaScript Online — Free JS Minifier (No Signup)
Minify JavaScript in the browser to shrink bundle size 40-60% and speed up page load. Free, client-side, preserves behavior. Works with ES modules and modern syntax.
How to Convert JSON to CSV Online — Free, No Installation
Convert JSON arrays to CSV spreadsheets in your browser. Handles nested objects, arrays, mixed schemas, and exports ready-to-open Excel, Numbers, or Google Sheets files.
How to Format SQL Online — Free SQL Beautifier (Postgres, MySQL, SQLite)
Format and beautify SQL queries online — proper indentation, capitalized keywords, aligned clauses. Supports Postgres, MySQL, SQLite, SQL Server syntax. Free, no signup.
How to Decode JWT Online — Free JWT Decoder (Header, Payload, Signature)
Decode JWT tokens instantly to read the header and payload. Verify the signature algorithm, inspect claims, and check expiry — free, in your browser, nothing logged.
How to Convert Markdown to HTML Online — Free, Instant Preview
Convert Markdown to clean HTML in your browser with live preview. Supports GitHub-flavored Markdown, tables, code highlighting, and safe HTML output. Free, no signup.
How to Generate Lorem Ipsum Online — Free Placeholder Text Generator
Generate Lorem Ipsum placeholder text in paragraphs, words, or characters. Free, instant, no signup. Classic Latin, modern alternatives, and custom lengths.
How to Convert Unix Timestamp Online — Free Epoch Time Converter
Convert Unix timestamps (epoch seconds or milliseconds) to human-readable dates and back. Supports any timezone, ISO 8601 output, and batch conversion.
SQL CTE Tutorial — WITH Clause + Recursive Queries with Examples
Master SQL Common Table Expressions (CTEs) — WITH clause syntax, when to use CTE vs subquery vs temp table, and recursive CTE examples for hierarchies and graph traversal.
How to Fix CORS Errors — Every Common Cause + Fix (2026)
The real reasons "Access-Control-Allow-Origin" errors happen and how to fix each one — preflight requests, credentials, wildcard origins, cache issues, and dev vs prod.
How to Write Good Git Commit Messages: A Practical Guide
Learn to write clear Git commit messages with Conventional Commits, the 50/72 rule, imperative mood, and how to fix bad messages with amend and rebase.
How to Set Up an Nginx Reverse Proxy (2026 Guide)
SEO how-to guide for configuring an Nginx reverse proxy with upstream, SSL, WebSockets, HTTP/2, and caching.
How to Fix SSL Certificate Errors: Complete Diagnostic Guide
Diagnose and fix common SSL/TLS errors including expired certs, hostname mismatch, missing intermediates, CAA blocks, and Let's Encrypt rate limits.
How to Fix React Hydration Mismatch Errors (Next.js Guide)
Fix the 'Hydration failed because the initial UI does not match' error in React and Next.js. The 6 top causes and proven patterns to fix each.
How to Write a Dockerfile: A Complete Practical Guide
Complete practical guide to writing production-ready Dockerfiles with multi-stage builds and real Node.js and Python examples.
How to Reduce Docker Image Size: 10 Proven Tactics
Shrink Docker images 70-90% with multi-stage builds, distroless bases, layer merging, and BuildKit cache — real before/after numbers included.
How to Fix ECONNREFUSED: Step-by-Step Diagnostic Guide
Fix ECONNREFUSED errors fast. Diagnose whether the process is running, listening on the right port and interface, and check firewalls plus Docker.
How to Fix 502 Bad Gateway Errors (Nginx, Cloudflare, Docker)
Diagnose and fix 502 Bad Gateway errors by checking upstream services, ports, proxy config, timeouts, and logs with real commands.
How to Increase Node.js Memory Limit (Heap Size Guide)
Fix 'JavaScript heap out of memory' errors by raising Node's V8 heap with --max-old-space-size, NODE_OPTIONS, npm scripts, PM2, and Docker.
How to Write Good API Documentation: A Practical Guide
Learn how to write clear, complete API documentation with OpenAPI, real examples, error codes, auth, rate limits, and the tools that render it well.
How to Fix Maximum Call Stack Size Exceeded in JavaScript
Diagnose and fix the RangeError: Maximum call stack size exceeded across recursion, circular JSON, React renders, and getter loops.
How to Fix SSH 'Permission denied (publickey)' Error
Step-by-step guide to diagnose and fix SSH 'Permission denied (publickey)' errors on Linux, macOS, and Windows using ssh-add, ssh -vvv, and permissions.
How to Fix Error: Cannot Find Module in Node.js
Diagnose and fix Node.js Error: Cannot find module 'X' — from missing installs and case sensitivity to ESM/CJS mismatches and TypeScript aliases.
Python Decorators: A Complete Tutorial with Real Examples
Complete Python decorators tutorial covering syntax, arguments, wraps, class decorators, and built-ins.
How to Fix 'Cannot Read Properties of Undefined' in JavaScript
Fix the JavaScript TypeError 'Cannot read properties of undefined' with optional chaining, defensive checks, async/await, and TypeScript strict mode.
Python Virtual Environment Tutorial: venv, uv, poetry, pyenv
Set up isolated Python environments with venv, virtualenv, pipx, pyenv, poetry, and uv. Activation on macOS, Linux, and Windows PowerShell explained.
How to Fix SSL/TLS Handshake Failure: Complete Debug Guide
Diagnose and fix SSL handshake failures. Debug protocol mismatches, cipher issues, cert chain problems, and SNI errors with openssl and curl.
How to Fix npm audit Vulnerabilities
Fix npm audit vulnerabilities using npm audit fix, --force, overrides, and manual bumps. Covers severity levels, transitive deps, and when to defer.
Fix 'Expected an Assignment or Function Call' in ESLint
How-to guide for fixing ESLint's no-unused-expressions error with four common causes and code fixes.
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