Developer Tools

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• Formatting JSON Safely

  How to format and validate JSON without losing precision, comments, or trust.

• How to Format JSON

  A step-by-step way to format and validate JSON without changing its values.

• What is JSON?

  A plain-language reference for the JSON data interchange format, its grammar, and its limits.

• JSON Formatter vs JSON Validator

  When to reformat JSON and when to validate it, and why the two tools answer different questions.

• Regex Groups and Captures

  How capturing and non-capturing groups work in a regular expression.

• Regex Syntax

  A reference for the core regular-expression syntax: classes, quantifiers, anchors, and groups.

• Common Regex Mistakes

  The regular-expression mistakes that cause failed matches and catastrophic backtracking.

• How to Encode and Decode Base64

  A step-by-step way to encode bytes to Base64 text and decode them back.

• What is Base64?

  A reference for Base64 encoding: what it is, its alphabet, and its size overhead.

• URL-safe Base64

  Why standard Base64 breaks URLs and how the URL-safe alphabet fixes it.

• Base64 vs Encryption

  Why Base64 is encoding and not encryption, and what each is actually for.

• Run a Job Every X Minutes with Cron

  How to express fixed and stepped minute intervals in a cron schedule.

• Cron Syntax

  A reference for the five cron fields and the values each accepts.

• Cron Time Zones

  How cron schedules interact with time zones and daylight saving time.

• How to Calculate the Difference Between Two Dates

  Count days between two dates and add or subtract days correctly, including leap years and inclusive ranges.

• Calculating Percentage Change Correctly

  Compute percent increase and decrease, and tell a percent change apart from a percentage-point difference.

• How to Convert Units Without Losing Precision

  Convert length, mass, temperature, and data-size units while keeping the ratio, prefix, and precision straight.

• How to Count Words and Characters

  Why word and character counts differ between tools, and how to choose a count that matches your purpose.

• How to Percent-Encode a URL

  Encode URLs and query components safely using the RFC 3986 reserved and unreserved character rules.

• Choosing a UUID Version: v4 versus v7

  When to use random UUID v4 and when a time-ordered UUID v7 is the better identifier.

• ISO 8601 and Unix Time

  How ISO 8601 date-time strings and Unix timestamps represent the same instant, and where precision changes the meaning.

• Percentage Points vs Percent

  The difference between a change in percentage points and a percent change, with concrete examples.

• SI Decimal Prefixes and Binary Prefixes

  Kilo, mega, and giga versus kibi, mebi, and gibi, and why a 1 TB drive reports less than 1 TiB.

• Unicode Text Segmentation

  How Unicode defines grapheme clusters and word boundaries, and why a character is not always one code point.

• URI Reserved and Unreserved Characters

  The RFC 3986 character classes and the hexadecimal escapes that keep a URI unambiguous.

• UUID Format, Versions, and Variants

  The 8-4-4-4-12 textual layout, the version and variant fields, and the RFC that defines them.

• Cryptographic Hash Functions, HMAC and Checksums

  How SHA-2, SHA-1, MD5, HMAC and non-cryptographic checksums differ, what each one proves, and when to choose which.