DuperThe format that's super!

A human-friendly extension of JSON with quality-of-life improvements, extra types, and semantic identifiers.

Hand-writing ergonomics

Trailing commas, comments, and optional quotes for keys.

Tuples, bytes, raw strings, Temporal, and proper integer support.

Identifiers provide readability, debuggability, and optional validation.

Every valid JSON file is automatically valid Duper.

Duper excels in a variety of use cases:

Configuration files: Duper's explicit types and comments serve as helpful guides when users need to modify values.
REST APIs: Extended type support and self-documenting identifiers make Duper a natural fit for API responses.
Logging: With a simple and readable syntax, Duper is a breath of fresh air for both manual and tool-assisted debugging.

Duper

Feature	Duper	JSON	JSON5	YAML	TOML	RON
Comments	✅	❌	✅	✅	✅	✅
Trailing commas	✅	❌	✅	✅	✅	✅
Unquoted keys	✅	❌	✅	✅	✅	✅
Integers	✅	❌	❌	✅	✅	✅
Tuples	✅	❌	❌	❌	❌	✅
Bytes	✅	❌	❌	✅^[1]	❌	✅
Date and time	✅^[2]	❌	❌	✅	✅	❌
Raw strings	✅	❌	❌	✅	✅	✅
Identifiers/tags	✅	❌	❌	✅	❌	✅
Unambiguous	✅	✅	✅	❌^[3]	⚠️^[4]	✅
Simple	✅	✅	✅	❌	✅	✅
JSON-compatible	✅	✅	✅	✅	❌	❌
Popular	❌	✅	⚠️	✅	✅	⚠️