Protocol Buffers - Google's data interchange format

C++ based gRPC (C++, Python, Ruby, Objective-C, PHP, C#)

LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.

A library that provides an embeddable, persistent key-value store for fast storage.

SQL powered operating system instrumentation, monitoring, and analytics.

A fast JSON parser/generator for C++ with both SAX/DOM style API

Fast and Lightweight Observability Data Collector