DevToolbox Blog

JSON · Beginner

How to Format JSON: A Complete Guide (2026)

JSON formatting, compression, and validation. 3 common errors, 4 FAQs, and a free online tool. Covers API debugging, config files, and log analysis.

JSON · Advanced

JSON Beyond Formatting: 10 Advanced JSON Tricks Every Developer Needs

JSON Schema / JSONPath / Diff / Performance / JSONC / JSON Lines + jq cheat sheet.

Base64 · Deep Dive

What is Base64 Encoding? A Developer's Guide

Base64 is not encryption! 3-bytes-to-4-chars principle, full 64-char index table, Base64 vs Base64URL differences, 4 common myths debunked.

URL · Encoding

URL Encoding: The Complete Developer's Guide

Percent-encoding rules, encodeURI vs encodeURIComponent differences, Python/JS examples, 4 FAQs, and a free online URL encoder/decoder.

Regex · Advanced

Regex for Beginners: From Zero to Pro

Character classes, quantifiers, groups, lookarounds explained. 4 real-world patterns (email, URL, phone, HTML), JS match/replace/test, 5 common pitfalls.

UUID · Selection

What is a UUID? The Developer's Guide (2026)

UUID v1/v3/v4/v5/v7 versions compared, 10⁻¹² collision math, UUID vs auto-increment trade-offs, 4 use cases, free UUID generator.

JWT · Auth

What is JWT? A Complete Developer's Guide

JWT 3-part structure, HS256 vs RS256 vs ES256, JWT vs Session in 5 axes, 4 production security risks (alg=none, localStorage, HTTPS, exp), free decoder.

JWT · Advanced

JWT Dual Token: Access + Refresh in Production

Node.js implementation, Refresh Token Rotation replay defense, jti+Redis blacklist, HttpOnly+SameSite cookies, 4 revocation strategies, 5 pitfalls.

Docker · Containers

Docker for Beginners: From Zero to Containerized

Image vs container, 5 essential CLI commands, Dockerfile instructions, multi-stage builds, Docker Compose v3.8, 4 use cases, 3 pitfalls, 5 FAQs.

Git · Version Control

Git Commands Cheat Sheet: 50+ Commands for Everyday Use

6 categories, 50+ commands: setup, workflow, branching, undo, remote, advanced. 6 scenarios, reflog lifesaver, 5 FAQs.

Auth · Security

OAuth 2.0 vs JWT: 4-Dimension Comparison + How to Choose

OAuth 4 roles + 4 grant types, JWT 3-part breakdown, comparison table, 4 scenario picks, recommendations, 5 FAQs.

PDF · Tool Suite

PDF Tools Complete Guide — All 8 Tools in One Place

Merge, split, compress, encrypt, watermark, rotate, extract text, extract images — all 8 tools with scenarios and 6 FAQs.

API · Backend

RESTful API Design: 10 Principles + Real-World Implementation

6 REST constraints, 10 design principles, Node.js/Express Todo API, 10 anti-patterns, REST vs GraphQL, 5 FAQs.

Cron · Scheduling

Cron Expression Guide: 5-Field Syntax + Real-World Examples

5/6-field syntax, 9 special characters, 10 real scenarios (backup/cleanup/reports), online parser for instant verification.

Hash · Cryptography

MD5 / SHA256 Hash Algorithms: Principles, Uses & Security

5 algorithms compared, why MD5 is broken, password storage rules, file integrity + blockchain use cases, online calculator.

HTML · Entities

HTML Entities: All Special Characters + XSS Defense Guide

15 must-know entities, 3 syntaxes, 3 XSS scenarios, online reference with 200+ characters and one-click copy.

HTTP · Status Codes

HTTP Status Codes: 1xx–5xx Explained + Debugging Guide

502 vs 504 debugging, REST API design cheat sheet, 418/451 easter eggs, online lookup with search and copy.

Formats · Selection

JSON vs YAML: Syntax Comparison + When to Use Each

5 key differences, YAML anchors/comments, config format decision guide, online bidirectional converter.

PDF · Split

How to Split PDF: 3 Ways to Split PDF by Page

Online tool / pdftk CLI / built-in reader, 3 real scenarios, free unlimited splits.

PDF · Compress

How to Compress PDF: 3 Ways to Reduce PDF File Size

Online compressor / Ghostscript CLI / 3 myths debunked, free online tool.

PDF · Encrypt

How to Password Protect a PDF: Encryption Guide

AES-128/AES-256 encryption, online tool + qpdf CLI, 30s to set password.

PDF · To Image

PDF to Image: 3 Easy Methods to Convert PDF Pages to PNG/JPG

3 methods compared + 72/150/300 DPI options + browser-local processing, no upload.

PDF · to Word

PDF to Word: Free Converter Guide

Online converter + Word built-in method, free, no watermark, client-side.

PDF · to Excel

PDF to Excel: Extract Tables into Spreadsheets

One-click extract PDF tables to .xlsx, save hours of manual data entry.

PDF · to PPT

PDF to PPT: Convert PDF to PowerPoint Slides

Per-page extraction to .pptx, fast PDF presentation recovery.

PDF · Watermark

How to Add Watermark to PDF: Step-by-Step Guide

Custom text/position/opacity, 3 pro tips, protect document rights.

PDF · Rotate

How to Rotate PDF Pages: Quick Guide

90°/180°/270° online rotation, no more tilting your head.

PDF · Extract

PDF Extract Guide: Extract Text & Images from PDF

Extract text as .txt + images as ZIP, client-side only.

Screenshot · to PDF

Screenshot to PDF: Turn Screenshots into PDF Documents

Ctrl+V paste to PDF, upload images, capture web, ultimate fragment tool.

SQL · Format

SQL Formatter: Beautify SQL Queries Online

One-click format SELECT/INSERT/UPDATE, clean indentation, keyword highlighting.

Timestamp · Convert

Unix Timestamp Converter: Seconds to Date

Auto-detect seconds/ms/ns, debug essential.

Image · Compress

Image Compression: PNG/JPG/WebP Online

Halve file size, no visible quality loss, double site speed.

QR · Code

QR Code Generator: Complete Online Guide

URL/WiFi/vCard to QR, SVG ready for print.

CSS · Minify

CSS Minifier: Compress & Beautify CSS Online

Strip whitespace and comments, essential pre-deployment step.

Network · IP

IP Lookup: Find IP Location & ISP

Locate any IP in one second, no CLI needed.

Text · Diff

Text Diff Checker: Compare Texts Online

Red deletions, green additions, best code review companion.

Password · Gen

Password Generator: Strong Random Passwords

Say goodbye to weak passwords, client-side only, pair with manager.