11 releases (7 stable)

25.12.19 Dec 19, 2025
25.9.23 Sep 24, 2025
25.2.10 Feb 11, 2025
24.12.23 Dec 23, 2024
0.1.1 Jun 29, 2020

#1657 in Encoding

Download history 136935/week @ 2025-10-21 156572/week @ 2025-10-28 146462/week @ 2025-11-04 153584/week @ 2025-11-11 100820/week @ 2025-11-18 13682/week @ 2025-11-25 15519/week @ 2025-12-02 12807/week @ 2025-12-09 13074/week @ 2025-12-16 7425/week @ 2025-12-23 6551/week @ 2025-12-30 10974/week @ 2026-01-06 11636/week @ 2026-01-13 10722/week @ 2026-01-20 11135/week @ 2026-01-27 11605/week @ 2026-02-03

47,078 downloads per month
Used in 79 crates (37 directly)

Apache-2.0

125KB
2.5K SLoC

Flexbuffers

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.

See Examples for Usage:

Flexbuffers is the schema-less cousin of Flatbuffers.

Dependencies

~0.5–1.1MB
~24K SLoC