JSONL (JSON Lines) stores one JSON value per line, so files and HTTP responses can be read, appended and streamed record by record. We compare JSONL with JSON arrays and NDJSON, check the media types, and read, write and stream JSONL in Python, Node.js and Java.
Written by: Lokesh Gupta
Published on:
JSON has no comments, so every strict parser rejects // and /* */. We look at why, the exact error each parser gives, the _comment key workaround, JSONC and JSON5 with their parsers, safe comment stripping, and why an API must never send or accept comments.
Learn which JSON key names are valid, how to escape special characters, duplicate and Unicode keys, and naming styles like camelCase and snake_case.
JSON Schema is a grammar language for defining the structure, content, and (to some extent) semantics of JSON objects. It lets you specify metadata (data about data) about what an object’s properties mean and what values are valid for those properties.
Learn JSONPath syntax from RFC 9535: selectors, filters and recursive descent, with real output from JavaScript and Python libraries and old vs new rules.
Learn JSON with Ajax: send and receive JSON with fetch() and XMLHttpRequest, set Content-Type, handle errors and timeouts, and avoid CORS issues.
Learn JSON object syntax: keys and values, nested objects, duplicate keys, accessing values in JavaScript and how a JSON object differs from a JS object.
Learn JSON array syntax with examples: arrays of objects, nested arrays, reading and looping in JavaScript, and how APIs return lists of items.
Learn JSON parse in JavaScript: the reviver function, parsing dates, safe error handling, real SyntaxError messages and big number precision.
