Discussions

JSON is a widely used data format for configuration, APIs, and data exchange. One limitation developers often notice is that JSON does not natively support comments. Many teams still try to include a JSON comment for documentation or context, but doing so can have implications on parsing and performance.

Adding comments directly in JSON files often breaks parsers because the standard strictly expects key-value pairs only. Developers sometimes use workarounds, like adding a "__comment" key or using tools that strip comments before parsing. While this can make files more readable and maintainable for humans, it introduces additional steps in processing. Parsers may need extra pre-processing to ignore or remove the comments, which can slightly affect performance, especially in large datasets.

For teams handling complex APIs or microservices, this small overhead can accumulate. Automated testing and validation pipelines must account for these comment fields or risk failures. Platforms like Keploy can help in these scenarios by generating test cases from real API traffic. Even when JSON files contain metadata or comment-like fields, Keploy can handle them effectively, ensuring tests remain reliable without slowing down development cycles.

The takeaway is that JSON comment are useful for human readability and collaboration but should be implemented thoughtfully. Using dedicated comment fields or external documentation tools is often safer than inserting traditional comments. By doing so, developers can maintain performance, ensure parser compatibility, and still provide meaningful context for teams and automated tools.