How to Format and Validate JSON, and Fix the Most Common Errors
What valid JSON looks like, why parsers reject it, and how to fix trailing commas, single quotes, unquoted keys and other frequent mistakes.
Guides
Short, practical explanations of the formats and ideas behind our tools: what they are, how they work and the mistakes to avoid.
What Is Base64 Encoding and When Should You Use It?
How Base64 works, why it makes data about a third larger, where it is used in practice, and why it is not a form of encryption.
UTM Parameters Explained: How to Tag Links So Your Reports Make Sense
The five UTM parameters, a naming convention that keeps analytics clean, and the common mistakes that split or overwrite campaign data.
HTTP Status Codes: What 301, 302, 404 and 500 Really Mean
A practical guide to the status codes you meet most often, the difference between permanent and temporary redirects, and how redirect chains hurt.
Cron Expressions Explained with Practical Examples
How the five fields of a cron expression work, what the special characters mean, and ready to use schedules for common jobs.
How JWTs Work and What a JWT Decoder Can and Cannot Tell You
The three parts of a JSON Web Token, the standard claims, why decoding is not verifying, and the mistakes that make tokens unsafe.
A/B Test Statistical Significance Without the Jargon
What a p-value and confidence level mean in plain language, how to plan sample size, and why peeking at results early gives false winners.
Linux File Permissions and chmod Numbers Explained
How read, write and execute permissions work for owner, group and others, what numbers like 755 and 644 mean, and which settings to avoid.