Implementation of SQL databases in client-server relationship for data synchronization is a general practice in the last few decades. Today, technological advances in database management system have introduced various NoSQL database types, which are popular in handling unstructured multimedia data simpler and faster. Hence, NoSQL database is suitable to be implemented in client's mobile device to overcome its computing resources and battery limitation. However, synchronization activities and establishing connection between NoSQL mobile client database and Server SQL database are complex due to dissimilar database platforms and framework implementation. Thus, a new sync gateway for mobile NoSQL JSON document database and server-side SQL database is created to handle one-way data synchronization activities via wireless connectivity. An experimentation to study sync gateway transmission speed performance is carried out by synchronizing images that represent unstructured data. The result is validated by using T-test analytical tool and has shown significance difference compared with existing sync gateway in reducing data transfer speed, thus it provides better client mobile device resources optimization. © 2018 Author(s).