Code Formatting Best Practices: JSON, XML, SQL, CSS & More

Readable code is maintainable code. Whether you're debugging a minified JSON API response, reviewing a collapsed SQL query, or trying to understand dense CSS — code formatting is the first step to clarity. This guide covers formatting best practices for 6 common formats.

Why Formatting Matters

• Debugging speed — formatted code reveals structure instantly
• Code review quality — reviewers can focus on logic, not syntax
• Error detection — mismatched brackets and tags become obvious
• Team consistency — shared formatting rules prevent style debates

Format-Specific Best Practices

JSON Formatting

JSON is the lingua franca of APIs. Always use 2-space indentation for readability:

// Minified (hard to read)
{"name":"Polymorpher","version":"2.0","tools":[{"id":1,"slug":"json-to-classes"}]}

// Formatted (clear structure)
{
  "name": "Polymorpher",
  "version": "2.0",
  "tools": [
    {
      "id": 1,
      "slug": "json-to-classes"
    }
  ]
}JSON

SQL Formatting

SQL queries become readable with keyword-aligned formatting:

-- Unformatted
SELECT u.name, o.total FROM users u JOIN orders o ON u.id = o.user_id WHERE o.total > 100 ORDER BY o.total DESC;

-- Formatted
SELECT u.name, o.total
FROM users u
JOIN orders o ON u.id = o.user_id
WHERE o.total > 100
ORDER BY o.total DESC;SQL

XML / HTML Formatting

Tag-aware indentation makes nested structures clear:

<catalog>
  <book id="1">
    <title>Clean Code</title>
    <author>Robert C. Martin</author>
    <year>2008</year>
  </book>
</catalog>XML

CSS Formatting

One property per line with consistent indentation:

/* Minified */
.btn{display:flex;padding:0.5rem 1rem;border-radius:8px;background:var(--accent);color:#fff}

/* Formatted */
.btn {
  display: flex;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
}CSS

Auto-Detection

A good formatter should auto-detect the input format. Polymorpher's Code Beautifier automatically identifies whether your input is JSON, XML, SQL, CSS, HTML, or C# — no manual selection needed.