What is JSONL / JSON-lines

JSONL, or JSON Lines, is a format for storing structured data where each record is a separate line in JSON format. This format is advantageous for handling large datasets, allowing for streaming processing and reading line by line. JSONL is widely used in big data processing, logging, and machine learning.

The design of JSONL aims to provide a simple and efficient way to handle JSON data. Unlike traditional JSON files, each line in a JSONL file is a complete JSON object, making incremental reading of data straightforward. Users can read and parse data line by line without loading the entire file into memory, which is particularly important for large datasets.

In practical applications, JSONL format is commonly used for data exchange and storage, such as when data is transferred from one system to another in data pipelines. The line-by-line nature of JSONL helps ensure data integrity and consistency. Additionally, many modern data processing tools and frameworks (like Apache Kafka and Spark) support JSONL format, making it an important tool for data scientists and engineers.

In the future, as the amount of data continues to grow, the JSONL format may become increasingly prevalent in data storage and processing, especially in scenarios requiring efficient data transfer and processing. However, there are some considerations when using JSONL, such as the relative complexity of parsing for intricate nested structures. Additionally, JSONL files lack a standard metadata description mechanism, which may affect data interpretability.