It is aimed at projects where spending time and space (many memory allocations) to be able to access or construct serialized data is undesirable, such as in games or any other performance sensitive applications. Access is close to the speed of raw struct access with only one extra indirection (a kind of vtable) to allow for format evolution and optional fields. FlatBuffers is also very suitable for use with mmap (or streaming), requiring only part of the buffer to be in memory. It requires 0 additional allocations (in C++, other languages may vary). It is available as Open Source on GitHub under the Apache license, v2 (see LICENSE.txt).
It was originally created at Google for game development and other performance-critical applications. FlatBuffers is an efficient cross platform serialization library for C++, C#, C, Go, Java, Kotlin, JavaScript, Lobster, Lua, TypeScript, PHP, Python, Rust and Swift.
