Guides & Tutorials
The formats and techniques behind the tools — JSON, XML, YAML, CSV, regular expressions, cron schedules, UUIDs, hashing and image formats — explained with examples that were run before they were published, the errors that actually happen, and the fixes that actually work.
TOML vs YAML vs JSON: Choosing a Configuration Format
TOML, YAML and JSON compared for configuration files: comments, types, nesting, dates, tooling and the ecosystems that chose each — with a decision guide and conversions.
6 min read · Updated 2026-09-18JSON Crack Alternative Without Signup: Viewing JSON as a Tree
JSON Crack draws JSON as a node graph. If you want a collapsible tree with path queries instead, here is how the two compare — checked September 2026.
5 min read · Updated 2026-09-18FreeFormatter Alternatives (2026): Where Its Tools Went
FreeFormatter.com has been retired and its tool pages now return 404. A verified map of where each formatter, validator, escaper and encoder moved.
6 min read · Updated 2026-09-11URL Encoding Explained: %20 vs +, Reserved Characters, When to Encode
What percent-encoding does, which characters are reserved, why forms use + for a space, and how encodeURIComponent, encodeURI and URLSearchParams differ.
9 min read · Updated 2026-09-11Sass vs SCSS vs LESS vs Stylus: Choosing a CSS Preprocessor
How Sass, SCSS, LESS and Stylus differ in syntax and modules, what native CSS nesting and custom properties replaced, and how to migrate between dialects.
9 min read · Updated 2026-09-11HTML Entities Explained: When to Escape &, <, > and Quotes
Which characters to escape in HTML text, attributes, URLs and scripts, how named, decimal and hex references differ, and why you keep seeing &amp;.
9 min read · Updated 2026-09-11YAML Multi-line Strings: | vs > vs Quoted (Indentation Rules)
How YAML literal | and folded > block scalars differ, what -, + and a digit change, when to quote instead, and why a run: block loses its line breaks.
9 min read · Updated 2026-09-11How to Validate JSON Against a Schema in Python and JavaScript
Validate JSON against a schema with Ajv in Node and jsonschema in Python: install, compile, read the error objects, and wire validation into CI.
9 min read · Updated 2026-09-11JSON Minify vs Gzip: What Actually Shrinks a Payload
Measured bytes for three JSON documents raw, minified, gzipped and brotlied: what minification saves once compression is on, and when it still matters.
8 min read · Updated 2026-09-18Escaping vs Parameterised Queries
Why escaping quotes does not stop SQL injection: numeric contexts, LIKE, identifiers, second-order attacks, and how prepared statements close the hole.
8 min read · Updated 2026-09-11How to Escape a Single Quote in SQL
How to escape a single quote in SQL: the ANSI doubling rule, MySQL backslashes, Postgres dollar quoting, Oracle q-strings, LIKE patterns and binding.
9 min read · Updated 2026-09-11SHA-256 vs MD5 vs HMAC: How Hashing Works and Which One to Use
What a cryptographic hash guarantees, why MD5 and SHA-1 are broken but fine for checksums, how HMAC differs from a hash, and why passwords need Argon2.
6 min read · Updated 2026-09-10UUID v4 vs UUID v7: Which Should You Use for Database Keys?
UUID v4 and v7 compared: why random v4 keys fragment B-tree indexes, how v7's timestamp fixes it, the collision math, and how to generate and store both.
7 min read · Updated 2026-09-10Cron Expression Syntax Explained: Fields, Special Characters and Real Schedules
Cron syntax field by field: ranges, the * , - / characters, the day-of-month OR day-of-week rule, DST pitfalls, and Quartz's six-field variant.
6 min read · Updated 2026-09-18Regular Expressions Explained: A Practical Cheat Sheet With Tested Examples
A practical regex cheat sheet: metacharacters, quantifiers, groups, lookarounds and JavaScript flags, with tested patterns for emails, dates and slugs.
7 min read · Updated 2026-09-10How EMI Is Calculated: The Formula, a Worked Example and an Amortization Schedule
The EMI formula with a worked example (₹10 lakh at 8.5% for 20 years), an amortization schedule, prepayment maths, and flat vs reducing-balance rates.
7 min read · Updated 2026-09-10How to Convert CSV to JSON in JavaScript, Python and the Browser
Tested CSV to JSON code for Node (papaparse) and Python (csv.DictReader), plus type inference, nested output, streaming, and the trip back to CSV.
7 min read · Updated 2026-09-10XML Namespaces Explained: Prefixes, Default Namespaces and Common Errors
What xmlns and xmlns:prefix do, how default namespaces scope and inherit, why attributes are excluded, and why XPath returns nothing on namespaced XML.
7 min read · Updated 2026-09-10YAML Anchors, Aliases and Merge Keys Explained (With Real Config Examples)
How &anchor, *alias and the <<: merge key work in YAML, where docker-compose, GitLab CI and Helm use them, the override order, and the errors they cause.
7 min read · Updated 2026-09-10GIF vs MP4: Why Every Major Site Converts GIFs to Video
GIF vs MP4 compared: file size, quality, and autoplay behavior — why Twitter and Imgur convert every GIF to video, and how to do the same in your browser.
2 min read · Updated 2026-06-05RAW vs JPEG: What You're Actually Choosing
RAW vs JPEG for photography: dynamic range, editing headroom, file sizes and workflow — plus what RAW-to-JPG converters actually do with your files.
2 min read · Updated 2026-06-05SVG vs PNG: Vector and Raster, Explained Properly
SVG vs PNG explained: how vector and raster images actually differ, what scales and what doesn't, and when converting SVG to PNG is the right call.
2 min read · Updated 2026-06-05What Is a HEIC File? (And Why Your iPhone Photos Won't Open)
HEIC files explained: why iPhones use them, which apps and devices can open them, and the fastest way to convert HEIC to JPG or PNG right in your browser.
2 min read · Updated 2026-06-05PNG vs JPG: The Differences That Actually Matter
PNG vs JPG compared: compression, transparency, quality loss and file size — with clear rules for when each format wins and how to convert between them.
2 min read · Updated 2026-06-05JPG vs WebP vs AVIF: Which Image Format Should You Use?
JPG, WebP and AVIF compared honestly: file size at equal quality, browser support, transparency and encode speed — plus a simple rule for choosing.
3 min read · Updated 2026-06-04How to Compress Images for the Web (Without Ruining Them)
Practical image compression guide: lossy vs lossless, picking the right quality level, why some files won't shrink, and how to compress in your browser.
4 min read · Updated 2026-06-04How to POST JSON with curl (Without Quoting Pain)
POST JSON with curl correctly: the Content-Type header, shell quoting on Linux/Mac vs Windows, sending from files with @, and pretty-printing responses.
2 min read · Updated 2026-06-04JSON Schema Tutorial: Contracts for Your JSON
Learn JSON Schema from zero: types, required properties, nested objects, arrays, formats — with a complete example and how to generate schemas from samples.
2 min read · Updated 2026-06-04How to Decode a JWT (and Why Decoding Isn't Verifying)
Decode any JWT in seconds: the three-part structure, Base64url quirks, code and no-code methods — and the critical difference between decoding and verifying.
2 min read · Updated 2026-06-04What is a CSV File? The Format Everyone Uses and Nobody Reads About
CSV explained properly: the RFC 4180 rules, how quoting really works, why Excel mangles your data, and when CSV beats JSON (and when it doesn't).
2 min read · Updated 2026-06-04Pretty Print JSON in JavaScript: stringify and Beyond
Master JSON.stringify's third argument: indentation, the replacer, console tricks, circular-reference errors, and displaying pretty JSON in HTML.
2 min read · Updated 2026-06-04Pretty Print JSON in Python: Every Method That Matters
All the ways to pretty print JSON in Python: json.dumps with indent, sort_keys, the python -m json.tool one-liner, files, and Unicode gotchas.
2 min read · Updated 2026-06-04What is Base64? Encoding Explained Without the Mystique
How Base64 works: 3 bytes become 4 characters, why the = padding exists, where it's used (JWT, data URIs, K8s secrets) — and why it's NOT encryption.
2 min read · Updated 2026-06-04Comments in JSON: Why They're Forbidden and What To Do Instead
JSON has no comments — by deliberate design. Here's why, which workarounds are safe (JSON5, JSONC, _comment keys), and how each ecosystem handles it.
2 min read · Updated 2026-06-04“Unexpected end of JSON input”: What It Means and How to Fix It
The real causes of 'Unexpected end of JSON input': empty responses, truncated payloads, and unclosed brackets — with the steps that find each one.
2 min read · Updated 2026-06-04How to Convert Excel to JSON (Without Writing Code)
Turn Excel or Google Sheets data into clean JSON in under a minute: paste cells directly or export CSV — with typed numbers, booleans, and proper quoting.
2 min read · Updated 2026-06-04How to Open a JSON File (and Actually Read It)
Three ways to open a .json file: instantly in your browser, in a proper editor, or in Excel/Sheets — plus why double-clicking shows you a wall of text.
2 min read · Updated 2026-09-18JSON vs XML: An Honest Comparison
JSON vs XML compared without tribalism: syntax, size, attributes, namespaces, schemas, tooling — and the cases where each format genuinely wins.
2 min read · Updated 2026-06-04YAML Tutorial: Read and Write It Without Fear
Learn YAML properly: mappings, lists, multi-line strings, anchors — and the indentation and typing pitfalls that break Kubernetes and CI configs.
2 min read · Updated 2026-06-04XML Tutorial: Structure, Syntax & Survival Skills
A working developer's XML tutorial: elements, attributes, namespaces, escaping, and well-formedness rules — with the errors that actually break parsers.
2 min read · Updated 2026-06-04JSON vs YAML: Which Format When?
JSON vs YAML compared honestly: syntax, comments, whitespace pitfalls, tooling, and performance — with clear rules for when each format wins.
2 min read · Updated 2026-06-04How to Fix Invalid JSON: Every Common Error, Decoded
Unexpected token? Unexpected end of input? Decode every common JSON parse error, find the exact broken line, and fix it — or auto-repair it in one click.
2 min read · Updated 2026-06-04JSON Examples: From Hello World to Real API Payloads
Copy-ready JSON examples: basic objects, arrays, nested structures, API responses, configuration files — each explained line by line.
2 min read · Updated 2026-06-04What is JSON? A Practical Introduction
JSON explained simply: what it is, its exact syntax rules, real examples, how it compares to XML, and how to read, write, validate and format it.
2 min read · Updated 2026-06-04