Crate rmp [] [src]

The Rust MessagePack Library

RMP is a pure Rust MessagePack implementation.

MessagePack is an efficient binary serialization format.

Warning this library is still in rapid development and everything may change until 1.0 comes.


To use rmp, first add this to your Cargo.toml:

rmp = "^0.7"

Then, add this to your crate root:

extern crate rmp as msgpack; // Or just `rmp`.


  • Convenient API

    RMP is designed to be lightweight and straightforward. There are low-level API, which gives you full control on data encoding/decoding process and makes no heap allocations. On the other hand there are high-level API, which provides you convenient interface using Rust standard library and compiler reflection, allowing to encode/decode structures using derive attribute.

  • Zero-copy value decoding

    RMP allows to decode bytes from a buffer in a zero-copy manner easily and blazingly fast, while Rust static checks guarantees that the data will be valid until buffer lives.

  • Clear error handling

    RMP's error system guarantees that you never receive an error enum with unreachable variant.

  • Robust and tested

    This project is developed using TDD and CI, so any found bugs will be fixed without breaking existing functionality.


This crate represents the very basic functionality needed to work with MessagePack format. Ideologically it is developed as a basis for building high-level abstractions.

Currently there are three large modules: encode, decode and value. More detail you can find in the corresponding sections.

Formally every MessagePack message consists of some marker encapsulating a date type and the data itself. Sometimes there are no separate data chunk, for example for booleans. In these cases a marker contains the value. For example, the true value is encoded as 0xc3.

Also note, that a single value can be encoded in multiple ways. For example a value of 42 can be represented as: [0x2a], [0xcc, 0x2a], [0xcd, 0x00, 0x2a] and so on.

In these cases RMP guarantees that for encoding the most compact representation will be chosen. On the other hand for deserialization it is not matter in which representation the value is encoded - RMP deals with all of them.


Almost all API are represented as pure functions, which accepts a generic Write and the value.


pub use value::{Value, ValueRef};



Provides various functions and structs for MessagePack decoding.


Provides various functions and structs for MessagePack encoding.


Contains Value and ValueRef structs and its conversion traits.