JSON vs TOML
Differences, use cases, and when to use each
JSON is the universal data interchange format; TOML is designed specifically for configuration files. TOML offers comments, explicit typing, and INI-inspired readability that JSON lacks, but JSON has broader tool support.
Quick Comparison
| Feature | JSON | TOML |
|---|---|---|
| Primary Use | Data interchange & APIs | Configuration files |
| Comments | Not supported | Supported (#) |
| Typing | Implicit (quotes for strings) | Explicit (strings always quoted) |
| Date/Time | Strings only | Native date/time type |
| Deep Nesting | Natural | Verbose with dotted keys |
When to Use Each
When to Use JSON
Use JSON for data interchange, API communication, and any non-configuration use case. JSON's universal support and parsing speed make it the default for data.
When to Use TOML
Use TOML for project configuration files where humans edit values directly, comments are helpful, and explicit typing prevents ambiguity (like the YAML 'Norway problem').
Pros & Cons
JSON
TOML
Verdict
JSON for data and APIs; TOML for configuration files. They serve different niches and rarely compete directly. Rust (Cargo.toml) and Python (pyproject.toml) have standardized on TOML for config.