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Latest commit f489a3f @kuenishi kuenishi Merge pull request #56 from msgpack/fix-travis-build
Fix travis-ci build

MessagePack Erlang


prequisites for runtime

Erlang/OTP, >= 17.0 Also based on the new msgpack spec 232a0d.

edit rebar.config to use in your application

{deps, [
  {msgpack, ".*",
    {git, "git://", {branch, "master"}}}

Simple deserialization

Ham = msgpack:pack(Spam),
{ok, Spam} = msgpack:unpack(Ham).

Stream deserialization

{Term0, Rest0} = msgpack:unpack_stream(Binary),
{Term1, Rest1} = msgpack:unpack_stream(Rest0),

String type

Now this supports string type!

Opt = [{enable_str, true}]
{ok, "埼玉"} = msgpack:unpack(msgpack:pack("埼玉", Opt), Opt).
 => {ok,[22524,29577]}

There are several options for msgpack:pack/2 and msgpack:unpack/2 . See msgpack:options() in msgpack.hrl.

Map Style

Since Erlang/OTP 17.0

msgpack:pack(#{ <<"key">> => <<"value">> }, [{format, map}]).

Or use old jiffy/jsx style

msgpack:pack({[{<<"key">>, <<"value">>}]}, [{format, jiffy}]),
msgpack:pack([{<<"key">>, <<"value">>}], [{format, jsx}]).

Ext type

Now msgpack-erlang supports ext type. Now you can serialize everything with your original (de)serializer. That will enable us to handle erlang- native types like pid(), ref() contained in tuple(). See test/msgpack_ext_example_tests.erl for example code.

Packer = fun({ref, Ref}, Opt) when is_reference(Ref) -> {ok, {12, term_to_binary(Ref)}} end,
Unpacker = fun(12, Bin) -> {ok, {ref, binary_to_term(Bin)}} end,
Ref = make_ref(),
Opt = [{ext,{Packer,Unpacker}}],
{ok, {ref, Ref}} = msgpack:unpack(msgpack:pack({ref, Ref}, Opt), Opt).

This is still experimental feature, so I'm waiting for your feedback.

Compatibility mode

To use as same with old spec:

OldHam = msgpack:pack(Spam, [{enable_str,false}]),
{ok, Spam} = msgpack:unpack(OldHam, [{enable_str,false}]).

Since 0.2.3 now it's false by default.

Further tests

See msgpack-erlang-tests for further tests


Apache License 2.0

Release Notes


  • Deprecate nil
  • Moved to rebar3
  • Promote default map unpacker as default format when OTP is >= 17
  • Added QuickCheck tests
  • Since this version OTP older than R16B03-1 are no more supported

0.3.5 / 0.3.4

  • 0.3 series will be the last versions that supports R16B or older versions of OTP.
  • OTP 18.0 support
  • Promote default map unpacker as default format when OTP is >= 18


  • Add OTP 17 series to Travis-CI tests
  • Fix wrong numbering for ext types
  • Allow packing maps even when {format,map} is not set
  • Fix Dialyzer invalid contract warning
  • Proper use of null for jiffy-style encoding/decoding


  • set back default style as jiffy
  • fix bugs around nil/null handling


  • supports map new in 17.0
  • jiffy-style maps will be deprecated in near future
  • set default style as map


0.2 series works with OTP 17.0, R16, R15, and with MessagePack's new and old format. But does not support map type introduced in OTP 17.0.

It also supports JSX-compatible mode.

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