Comparing XML and JSON Characteristics as Formats for Data Serialisation Within Ultra-Low Power Embedded Systems

JavaScript Object Notation (JSON) and eXtensible Markup Language (XML) are two data serialisation methods that have been compared over many applications, including client-server transmission, Internet communication, and large-scale data storage. Due to the smaller file size, JSON is faster for transmitting data. However, XML is better for sending complex data structures. This letter compares the two data formats in the context of an embedded system, considering factors such as time, memory, and power to identify efficient characteristics of each method. Programs for each format were written, optimised, and compared for the same dataset. The JSON file was found to be 24.7% smaller than the XML file. This led to a shorter program run-time and less power being consumed when reading and processing the file. However, the program to deserialize the XML file took up 16.7% less flash memory than its JSON counterpart. Overall, JSON was found to be a better choice for systems when collecting large amounts of data, requiring high speed communication, or running for an extended period between battery charges. However, XML is proposed for systems that have limited flash memory.