Devtoolry Blog
Hands-on guides to the formats, encodings and tools developers use every day. Each article explains how something works, walks through real examples, and points out the mistakes that cause bugs in production.
All articles
Web DevelopmentHow to Compress a PDF Without Losing Quality
Why PDFs get large and how to shrink them for email and upload limits while keeping text sharp: what to compress, which settings to pick and what to avoid.
· 6 min read
JSON & Data FormatsCommon JSON Syntax Errors and How to Fix Them
Trailing commas, single quotes, comments, NaN and invisible characters: what each JSON parse error means, how to find the exact line, and how to fix it.
· 7 min read
Time & SchedulingCron Expressions Explained: Syntax, Examples and Common Mistakes
Read and write cron schedules with confidence: the five fields, steps and ranges, 20 ready-to-use examples, the day-of-week OR trap, time zones and DST.
· 6 min read
Code Quality & WorkflowHow to Read a Diff: The Unified Diff Format Explained
Understand every line of a unified diff: file headers, @@ hunk headers, context lines and + and - changes, plus git diff extras, patches and code reviews.
· 5 min read
Web DevelopmentHTML Meta Tags That Matter for SEO and Social Sharing
The meta tags every page needs: title, description, canonical, robots, viewport, Open Graph and Twitter Cards, with lengths, examples and tags to skip.
· 5 min read
JSON & Data FormatsJSON vs YAML vs XML: Which Data Format Should You Use?
A practical comparison of JSON, YAML and XML: syntax, comments, types, tooling and performance, with clear advice for APIs, config files and documents.
· 5 min read
Security & EncodingJWT Explained: Structure, Claims and How to Verify a Token
What is inside a JSON Web Token, how the signature works, which claims to check, and the security mistakes (alg none, weak secrets, storage) that break JWTs.
· 6 min read
Code Quality & WorkflowRegular Expressions for Developers: 12 Patterns You'll Actually Use
Tested regular expressions for emails, dates, UUIDs, versions and logs, plus groups, lookaheads, greedy vs lazy matching and catastrophic backtracking.
· 6 min read
Programming LanguagesThe JavaScript Event Loop: Promises, setTimeout and Microtasks in Practice
Why setTimeout(fn, 0) runs after promises, how await pauses, why busy loops delay timers, and how to run async work in sequence or parallel, with tested output.
· 5 min read
Time & SchedulingUnix Timestamps Explained: Seconds, Milliseconds and the Year 2038
What a Unix timestamp is, how to tell seconds from milliseconds, converting in JavaScript, Python and SQL, the date-only parsing trap, and the 2038 problem.
· 5 min read
Security & EncodingWhat Is Base64 Encoding? How It Works and When to Use It
How Base64 turns bytes into text, why it adds 33% to the size, Base64 vs Base64URL, handling UTF-8 in JavaScript, and why Base64 is never encryption.
· 5 min read
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