Developer Guides
Practical guides for every tool — how they work, when to use them, and real workflow examples.
SSD1306 Bitmap Scrambled or Sideways? It's the Draw Mode and Byte Order
Why a bitmap shows up scrambled, sideways, sheared or mirrored on an SSD1306 OLED, how to tell the cause from the pattern, and the one setting that fixes each.
GraphQL Playground Guide: Test Queries, Variables, and Schemas
Learn how to run GraphQL queries with variables and headers, inspect responses and schema types, and turn successful requests into reproducible cURL commands.
Why Does DateTime.ToString() Differ on Windows and Linux?
A C# date can print differently across machines. Check culture, DateTime.Kind, time zone, and ICU/NLS, then use explicit formatting for reliable logs and APIs.
SQL Runner Guide: Test SQLite Queries in Your Browser
Use an in-browser SQLite database to prototype schemas and queries, inspect results, and understand what still needs testing on your production database.
How ASP.NET Core Reads Environment Variables (and Why It's Double Underscore)
Turn appsettings.json into environment variables for Docker Compose, Kubernetes and Azure App Service: the __ separator, arrays, nulls, prefixes, and the quoting that breaks deployments.
HEX, RGB, HSL, OKLCH — Which Color Format to Use in Modern CSS
What each CSS color format is good for, why OKLCH is replacing HSL in design systems, what 'out of gamut' means, and how to convert without silently changing the color.
WCAG Contrast Ratios Explained — AA vs AAA and What Counts as Large Text
How the WCAG 2 contrast ratio is calculated, the thresholds for AA, AAA and UI components, why 4.48 fails, how transparency changes the math, and what APCA is.
Modbus RTU CRC-16 Explained, with Arduino Code
How the Modbus RTU CRC-16 works, why the bytes go on the wire low byte first, how to tell CRC-16 variants apart, and a tested C function for Arduino and ESP32.
Convert a Browser Request to C# HttpClient Code (the Copy as cURL Workflow)
Capture any request with DevTools' Copy as cURL and turn it into correct C# HttpClient code: content headers, cookies, compression, multipart uploads, and keeping tokens out of what you share.
Display a Custom Logo on an SSD1306 OLED with Arduino and ESP32
Convert a logo into a C byte array for a 128×64 SSD1306 OLED: choosing the right byte layout, thresholds and dithering, PROGMEM on AVR vs ESP32, and debugging scrambled or inverted images.
Two's Complement and IEEE 754 Floats for Firmware Developers
A practical guide to reading raw sensor and protocol bytes: two's complement signed integers, endianness, and how float32 values are stored — with the traps that cause real bugs.
Generate EF Core Entities from an Existing SQL Table (Without Scaffolding the Whole Database)
Turn a CREATE TABLE script from SQL Server, PostgreSQL, MySQL or SQLite into EF Core entity classes — keys, nullability, identity columns, foreign keys and the type-mapping traps.
Unix Timestamps: Seconds vs Milliseconds, Time Zones, and the 2038 Problem
How to read a Unix timestamp correctly — telling seconds from milliseconds, converting to any time zone, handling daylight-saving gaps and overlaps, and why 2038 still matters.
Regex Tester Guide: Build and Debug JavaScript Patterns
Learn how to test regular expressions, inspect capture groups, choose flags, and avoid common JavaScript regex mistakes with practical examples.
Debug Cron Schedules: Fields, Timezones & Next Runs
Check a five-field cron expression with reproducible next-run examples, local timezone assumptions, and the day-of-month versus weekday trap.
Convert YAML to JSON Without Losing Config Types
Convert a Kubernetes ConfigMap between YAML and JSON, preserve string values, and understand comments, duplicate keys, and document limitations.
Hash Generator: MD5, SHA-256, and When to Use Each Algorithm
A practical guide to cryptographic hashing — what MD5, SHA-1, SHA-256, SHA-384, and SHA-512 are good for, how to hash files in the browser, and the difference between hashing and encryption.
How to Decode a JWT: A Complete Guide to Reading and Verifying JSON Web Tokens
Everything you need to understand a JWT — header, payload, claims, expiry, signature verification, and the security warnings you should pay attention to.
URL Encoding Explained: encodeURIComponent vs encodeURI and When to Use Each
Understanding percent-encoding, the difference between component and full URL encoding modes, and practical scenarios where URL encoding matters in everyday development.
Base64 Encoding Explained: What It Is, When to Use It, and How to Encode Files
A practical guide to Base64 — what it does, why developers use it, the difference between Base64 and Base64URL, and how to encode files and images in the browser.
HTML Minifier: Shrinking Markup Without Breaking Your Pages
What HTML minification removes, how the preserve-comments option works, and when minifying HTML actually matters for performance.
JavaScript Minifier: What It Does, When to Use It, and Its Limits
A practical look at browser-based JS minification — what transformations are applied, where it fits in a real workflow, and why it's not a replacement for Terser or esbuild.
CSS Minifier & Beautifier: Practical Guide to Shrinking and Reading CSS
When to minify CSS, what a browser-based minifier actually does, how to use beautify mode for debugging vendor CSS, and how it fits into a modern front-end workflow.
JSON to SQL: Infer Table Schemas from JSON Objects
How to use a JSON-to-SQL converter to draft CREATE TABLE statements from API responses, log structures, and document schemas — with practical examples and limitations.
C# Class to SQL Table: Generate CREATE TABLE from Your Entities
How to scaffold SQL CREATE TABLE statements from C# entity classes for SQL Server, MySQL, and PostgreSQL — what gets mapped, what doesn't, and how to use the output.
JSON to C# Class Generator: From API Response to POCO in Seconds
How to use a JSON-to-C# converter to scaffold model classes from real API responses, database records, and config objects — and what to watch out for afterward.
C# Class to JSON: Generate Sample Payloads from Your Models
How to turn C# classes into example JSON payloads for API docs, tests, and integration work — without running any code.
SQL Formatter: Why Dialect Matters and How to Format Queries Properly
A practical guide to formatting SQL across T-SQL, PostgreSQL, MySQL, and SQLite — why dialect-aware formatting matters and how it fits into a real dev workflow.
How to Format & Validate JSON
How to get real value out of a browser-based JSON formatter — formatting messy API payloads, catching parse errors early, and keeping your workflow fast.