Flexbuffers is a schema-less binary format developed at Google. FlexBuffers can be accessed without parsing, copying, or allocation. This is a huge win for efficiency, memory friendly-ness, and allows for unique use cases such as mmap-ing large amounts of free-form data.
FlexBuffers' design and implementation allows for a very compact encoding, with automatic sizing of containers to their smallest possible representation (8/16/32/64 bits). Many values and offsets can be encoded in just 8 bits.
FlexBuffers supports Serde for automatically serializing Rust data structures into its binary format.
Flexbuffers is the schema-less cousin of Flatbuffers.