GuidesWhat Is JSON? A Practical Guide for Developers
What Is JSON? A Practical Guide for Developers
Updated 2026-07-23 · SparkJSON
JSON (JavaScript Object Notation) is a lightweight text format for structured data. APIs, configs, and logs use it because it’s readable, language-agnostic, and easy to parse — as long as you follow its strict syntax rules.
JSON data types
JSON supports objects, arrays, strings, numbers, booleans, and null. Dates are usually ISO-8601 strings. Binary data is often Base64-encoded strings.
JSON vs XML
JSON is typically smaller and easier to map to objects in modern languages. XML shines with mixed content, schemas with long histories, and document-centric markup. Most new HTTP APIs default to JSON.
Working with JSON day to day
Format for reading, minify for transport, validate before shipping. SparkJSON covers the interactive loop; your language’s standard library covers production parsing.
FAQ
- Is JSON only for JavaScript?
- No. The name comes from JavaScript, but every major language has JSON libraries. It is a data interchange format, not a programming language.