By JSONConvert Team·March 2, 2026·5 min read

YAML vs JSON for Config Files

Every project needs configuration. The two most common formats are JSON and YAML. Both represent the same data structures, but they have different strengths. Here's when to use each.

Quick Comparison

Feature	JSON	YAML
Comments	No	Yes (`#`)
Readability	Verbose	Clean
Parsing speed	Fast	Slower
Multiline strings	Escaped `\n`	Block scalars (`\`	, `>`)
Data types	6 (string, number, boolean, null, object, array)	Same + dates, binary
Indentation	Not significant	Significant
Trailing commas	Invalid	N/A
Tooling	Universal	Good

When to Use JSON

API responses and data exchange. JSON is the universal data format. Every language parses it natively, and there's zero ambiguity about types. Programmatically generated config. If your config is written by code (not humans), JSON is simpler to generate - no indentation concerns. package.json, tsconfig.json, etc. The JavaScript/TypeScript ecosystem standardized on JSON. Use what the ecosystem expects. When you need speed. JSON parsers are significantly faster than YAML parsers.

When to Use YAML

Human-edited config files. YAML is more readable for humans:

vs. JSON:

When you need comments. JSON doesn't support comments. If your config needs explanations, YAML wins. Docker Compose, Kubernetes, CI/CD. These ecosystems standardized on YAML. Use what the tooling expects. Multiline strings. YAML handles multiline content cleanly:

Converting Between Formats

Need to convert? Our tools handle both directions:

JSON to YAML - Convert JSON config to YAML

YAML to JSON - Convert YAML back to JSON

Common scenarios:

Converting docker-compose.json to the standard .yml format

Converting YAML CI config to JSON for programmatic manipulation

Migrating between config formats during a project restructure

YAML Gotchas

YAML has some well-known footguns:

The Norway problem. In YAML 1.1, NO is parsed as boolean false. Country codes, abbreviations, and other short strings can be silently converted:

YAML 1.2 fixes this, but not all parsers use 1.2.

Indentation errors are silent. A misaligned key creates a different structure without any error:

String type coercion. 1.0 is a float, 1 is an int, 1.0.0 is a string. Version numbers like 3.10 become 3.1. Always quote version strings.

The Verdict

Use JSON for: APIs, data exchange, programmatic config, JavaScript/TypeScript ecosystems.

Use YAML for: human-edited config, DevOps tooling (Docker, K8s, GitHub Actions), anything that benefits from comments.

Both are fine choices. Pick what your team and tooling expect, and convert between them when needed with our JSON to YAML and YAML to JSON converters.