Technical Articles
How PDF Files Work: Pages, Objects, Text Layers, and Merging
Markdown, HTML, PDF and DOCX: Choosing a Format for Each Step
UTF-8 vs Shift-JIS: Why Text Encoding Bugs Still Happen
Each article is written around a real technical topic instead of a reusable how-to template.
Use the articles to understand the format, boundary, and failure modes before opening a related tool.
Articles are maintained around technical topics, privacy boundaries, and verifiable behavior.
Each article links back to relevant tools so you can finish the task after reading.
How PDF Files Work: Pages, Objects, Text Layers, and Merging
A practical explanation of how PDF files are structured, what really happens when PDFs are merged, and which details should be checked before sharing a final document.
Markdown, HTML, PDF and DOCX: Choosing a Format for Each Step
Markdown is for writing, HTML for the browser, PDF for fixed layout and DOCX for collaboration. How content changes when it moves between them.
UTF-8 vs Shift-JIS: Why Text Encoding Bugs Still Happen
A technical explanation of Unicode, UTF-8, Shift-JIS, byte sequences, mojibake, and how to debug encoding problems with small samples.
JSONPath for API Payloads: Querying Nested Data Without Writing a Script
A technical introduction to JSONPath as a debugging tool for nested JSON responses, including paths, filters, arrays, and implementation differences.
Cron Expressions Explained: Fields, Time Zones, and Deployment Risks
A technical article on how cron expressions are read, why schedules are misinterpreted, and how to verify future runs before deploying jobs.
Time Zones Explained: Offsets, IANA Names, DST, and Launch Planning
A technical article on why offsets are not time zones, how daylight saving changes schedules, and how to communicate launch windows clearly.
QR Codes Explained: Payloads, Error Correction, Scan Distance, and Safety
A technical article on how QR codes store data, why payload length and error correction matter, and how to verify a code before publishing it.
EXIF Metadata Explained: GPS, Orientation, Camera Tags, and Privacy
A technical article on what EXIF metadata can reveal, why GPS and orientation fields matter, and how to review images before publishing.
Hex and Bytes Explained: Reading File Headers, Encodings, and Binary Clues
A technical guide to hexadecimal inspection, byte order, file signatures, BOM markers, and why byte-level debugging helps with format problems.
RSA Keys Explained: Encryption, Signatures, Padding, and Private Key Safety
A technical article on RSA public and private keys, why padding matters, how signing differs from encryption, and why demos are not key management.
JSON and CSV Are Not Equivalent: What Gets Lost During Conversion
A practical technical article on converting between JSON and CSV, including nesting, headers, quoting, nulls, types, and spreadsheet assumptions.
JWTs Explained: Decoding Claims Without Confusing Them With Validation
A practical explanation of JWT structure, claims, Base64URL encoding, signatures, and why decoding a token is not the same as trusting it.
From docker run to Compose: What Each Flag Really Means
A technical guide to translating docker run commands into Compose services while preserving ports, volumes, environment variables, restart rules, and secrets.
Word Count Rules: Why Two Tools Disagree About the Same Text
What counts as a word depends on the tool. How hyphens, numbers and citations are treated, what academic limits usually exclude, and why CJK text is counted differently.
Counting Words in Mixed Chinese and English Text
Whitespace splitting fails on Chinese. How bilingual counters should segment each script, and what totals mean when both appear in one document.
Why Valid JSON Breaks: Commas, Numbers, and Escapes
JSON is stricter than it looks. What a parser error position really tells you, why long IDs change value, and what a formatter can never catch.
JSON Validation vs Formatting: Syntax, Shape, and Schema Are Different
A technical article explaining what JSON formatters can and cannot prove, how syntax differs from schema, and how to review payloads safely.
Base64 Explained: Encoding, Padding, Data URLs, and Common Mistakes
A technical article on how Base64 turns bytes into text, why padding exists, how URL-safe variants differ, and why Base64 is not encryption.
Cleaning Text Before Import: Hidden Characters That Break Pipelines
BOM markers, non-breaking spaces, smart quotes and mixed line endings are invisible until a parser rejects the file. What to strip and what to keep.
Unix Timestamps Explained: Seconds, Milliseconds, UTC, and Log Debugging
A practical guide to Unix timestamps, unit confusion, UTC display, JavaScript milliseconds, and how to read time fields in logs and APIs.
UUIDs Explained: Versions, Randomness, Sorting, and Safe Use
A technical guide to UUID versions, why v4, v5, and v7 behave differently, and where UUIDs are useful or misleading in application design.
SHA-256 Explained: Hashes, Integrity Checks, Salts, and Misuse
A practical guide to SHA-256 hashing, file integrity checks, password caveats, collision resistance, and why hashes are not encryption.
URL Encoding Explained: Percent Encoding, Query Strings, and Safe Links
A technical article on percent encoding, query parameters, path segments, form encoding, and why URLs break when reserved characters are copied raw.
Unit Conversion: Exact Definitions and Where Conversions Go Wrong
An inch is exactly 25.4 mm and a pound is exactly 0.45359237 kg. Which conversions are exact, which are not, and why temperature and fuel economy behave differently.
Reading Time Estimates: What the Minutes Actually Mean
Reading time is word count divided by an assumed speed. Which speeds are realistic, how code and images change the number, and when to show it to readers.
Keyword Density: What the Percentage Means and What It Does Not
Keyword density is a count, not a ranking strategy. How to measure it in English and Chinese, and why stuffing still hurts more than it helps.
Percentage Change: The Formula and Four Ways It Misleads
How to compute percent change correctly, why percent and percentage points are different, and why a 50% drop needs a 100% rise to recover.
Encryption Basics in the Browser: Hashing, Symmetric Keys and What Stays Local
Hashing is not encryption. Symmetric encryption needs a secret both sides share. What browser-side crypto can and cannot protect.
Reading CIDR Notation: Prefixes, Hosts, and Range Checks
What the number after the slash means, how many addresses a prefix really gives you, and how to check whether an address falls inside a range.
Exchange Rates for Pricing: Spot, Mid-market and the Spread You Actually Pay
The rate on a news site is not the rate on an invoice. How mid-market, bid and ask differ, and how to avoid silent margin errors.
Protocol Buffers Explained: Schemas, Field Numbers, and Binary Debugging
A technical introduction to protobuf payloads, why schemas are required, how field numbers work, and what to inspect when binary messages fail.
Split, Compress and Reorder PDF Pages Without Losing the Wrong Content
Page ranges, file size and reading order are three different jobs. How to split cleanly, compress safely and check the result.
Extracting Text and Images from PDFs: Selectable Text versus OCR
If you can select text, extract it. If the page is only an image, you need OCR. How to tell which case you have and what quality to expect.
Password-Protecting and Sharing PDFs: Permissions, Owners and Real Limits
A PDF password is not full encryption theatre. What user and owner passwords do, which permissions actually stick, and what recipients can still do.
PDF and Office Conversion: What Survives Round Trips
DOCX to PDF is usually reliable. PDF to DOCX is reconstruction. How to choose a direction and validate the result.
Image Formats Explained: JPEG, PNG, WebP, AVIF, HEIC, and Resizing Order
A practical technical article on choosing image formats, resizing before compression, preserving transparency, and preparing batches for upload.
Background Removal and Upscaling: Clean Product Images Without Plastic Edges
Cutouts fail on hair, glass and soft shadows. Upscaling invents detail. How to review AI edits before you publish them.
Reading a JWT: What Decoding Shows and What It Proves
A JWT is three base64url segments, and decoding one tells you nothing about whether it is genuine. How to read the claims, and why tokens break in URLs.
Barcodes, QR Codes and OCR Labels: Generate, Scan and Verify
A code that cannot be scanned is decoration. How to choose barcode versus QR, size codes for print, and verify before a print run.