What Is utily.tools?
Learn how utily.tools brings practical developer utilities together in one browser-based workspace.
Articles
Guides, explanations and practical ideas to help you get more from developer tools.
Online Text Editors: How Text Transformation Works
Learn how online text editors normalize, split, replace, count and transform text, with technical examples and practical use cases.
Text Templates and Variables: A Practical Automation Guide
Understand how text templates replace variables to generate consistent messages, commands and documents, including grammar, rendering rules and examples.
Text Diff Explained: Algorithms, Changes and Real Uses
Learn how text diff tools detect additions, removals and unchanged sequences using LCS-style algorithms, with technical examples.
Base64 Encoding and Decoding: How It Really Works
Understand Base64 encoding, its 24-bit conversion process, padding, UTF-8 handling and practical uses in APIs, email and data URLs.
URL Encoding Explained: Percent-Encoding in Practice
Learn how URL percent-encoding represents reserved characters and UTF-8 bytes in paths and query strings, including standards, normalization and security.
URI vs URL: The Difference Explained with Examples
Understand the difference between URI, URL and URN: RFC 3986 definitions, generic syntax, schemes, relative references and real code examples.
Swagger and OpenAPI: History, Versions and Technical Differences
The history of Swagger and OpenAPI, who standardizes the specification, and the technical differences between Swagger 2.0, OpenAPI 3.0 and 3.1.
JSON Formatting, Minification and Validation Explained
A technical guide to JSON syntax, parsing, formatting, minification and stringification for APIs, configuration and web applications.
How to Compare JSON and YAML Structurally
Learn how structural comparison parses JSON and YAML, walks object paths and reports missing fields and different values.
UUID v1, v4 and v7: Generation, Structure and Uses
Compare UUID v1, v4 and v7, understand their bit layout, randomness, ordering and practical use in distributed systems.
Unix Timestamps: Epoch Time, Precision and Time Zones
Understand Unix timestamps in seconds and milliseconds, UTC conversion, time zones, precision and practical application behavior.
CPF and CNPJ Check Digits for Software Testing
Learn how CPF and CNPJ check digits are calculated, why valid test documents matter and how to use generated values responsibly.
JWT Explained: Structure, Claims, Signing and Validation
A technical guide to JSON Web Tokens, Base64url segments, registered claims, signatures, key formats and secure validation.
JWE Explained: Encrypted Tokens and Compact Serialization
Understand JSON Web Encryption, key management algorithms, authenticated content encryption and the five compact JWE segments.
Cryptographic Hash Functions: MD5, SHA-1 and SHA-2
Learn how cryptographic hashes process data, which security properties matter and when to use SHA-256, SHA-384 or SHA-512.
HMAC Explained: Authenticating Messages with a Secret Key
Understand HMAC construction, secret-key management, canonical messages and signature verification for APIs and webhooks.
Secure Password Generation: Entropy, Randomness and Policy
Learn how password generators use cryptographic randomness, character pools and entropy, and how to choose practical password policies.
How to Read an X.509 Certificate
Learn how X.509 certificates encode subjects, issuers, validity, public keys, extensions, signatures and fingerprints.
Generating RSA Keys and Self-Signed X.509 Certificates
A practical guide to RSA key generation, certificate fields, self-signing, PEM, DER, PFX, PKCS#8 and JWK exports.
Certificate and Private-Key Validation in Practice
Learn how to validate certificate dates, inspect formats and prove that public and private RSA keys belong to the same pair.
OCR Explained: How Images Become Editable Text
Learn how optical character recognition preprocesses images, detects text and uses trained language models to produce editable content.
QR Codes: Encoding, Error Correction and Design
Understand QR Code structure, data modes, Reed–Solomon error correction, masking and the design rules behind reliable custom codes.
How PDF and Image Merging Works in the Browser
Learn how PDF pages are copied, images are embedded, dimensions are preserved and mixed files become one downloadable document.
PDF Splitting and Page-to-JPG Rendering Explained
Understand how PDF pages are extracted without rasterization and how content streams are rendered into JPG images and packaged downloads.
Creating a PDF from Images in the Browser
Learn how image files are decoded, ordered, embedded and scaled into PDF pages through image sampling, page geometry and compression.
Real-Time Text Sharing with WebSockets and Channels
Learn how Socket.IO channels synchronize text, presence and short-lived history across browser screens in real time.
IPv4 CIDR Explained: Subnet Masks and IP Ranges
Learn IPv4 history, binary addressing, subnet masks and CIDR calculations, including network, broadcast and usable ranges for /24, /22 and other prefixes.