Can you use comments in JSON?

No. Standard JSON does not support comments. The format was intentionally kept minimal for data interchange, so // and /* */ will cause a parse error. There are, however, a few common workarounds.

{
  // the user's name
  "name": "Ada"
}

Workarounds

• Use a "comment" key: add a harmless field like "_comment": "note here" that your code ignores.
• Use JSONC or JSON5: relaxed supersets that allow comments. Many tools (VS Code settings, tsconfig.json) use JSONC.
• Strip comments before parsing: some loaders remove comments first, but standard JSON.parse will not.

Getting an error from a stray comment? The JSON validator points to the exact line.