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postcard

A no_std + serde compatible message library for Rust

jamesmunns/postcard94M downloads/moNew releases in your daily digest, changelog included.

Latest stable

1.1.3

Last release 1 years ago
24 Jul 2025
Release timing varies
gaps range from 9 days to 11 months
Some releases are documented
notes for 14 of 35 stable releases
1 version withdrawn
withdrawn after publishing
8 years old
40 releases · first in 2019

Releases on this page

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1.1.324 Jul 2025
postcard2: Initial commit by @jamesmunns in https://github.com/jamesmunns/postcard/pull/251
What's Changed

postcard2: Initial commit by @jamesmunns in https://github.com/jamesmunns/postcard/pull/251

Address clippy lints by @max-heller in https://github.com/jamesmunns/postcard/pull/256

Respect #[serde(rename = "name")] attributes by @max-heller in https://github.com/jamesmunns/postcard/pull/257

Fix missing license files in published crates by @musicinmybrain in https://github.com/jamesmunns/postcard/pull/227

postcard v1.1.3 (and friends) by @jamesmunns in https://github.com/jamesmunns/postcard/pull/261

Full Changelog: https://github.com/jamesmunns/postcard/compare/postcard/v1.1.2...postcard/v1.1.3
Open source →
Additional notes
This project publishes no release notes. Between postcard/v1.1.2 and postcard/v1.1.3 there were 12 commits, 7 of them substantive:

Fix missing license files in published crates

postcard2: Initial commit

Update postcard-derive-ng version

Address clippy lints

Respect #[serde(rename = "name")] attributes

Prep for release

Update everyone that got a license added
1.1.225 Jun 2025
Implement MaxSize for serializable Range structs by @ChocolateLoverRaj in https://github.com/jamesmunns/postcard/pull/193
What's Changed

Implement MaxSize for serializable Range structs by @ChocolateLoverRaj in https://github.com/jamesmunns/postcard/pull/193

docs: Add notes on serde attributes by @ManevilleF in https://github.com/jamesmunns/postcard/pull/191

Fix EOF not being handled correctly by @sommd in https://github.com/jamesmunns/postcard/pull/202

Add Serialize and Deserialize traits to postcard::Error by @quietlychris in https://github.com/jamesmunns/postcard/pull/215

Remove paste dependency by @Gerharddc in https://github.com/jamesmunns/postcard/pull/222

Reduce unsafety and add safety comments to remaining unsafe code by @Veykril in https://github.com/jamesmunns/postcard/pull/237

Fix Typos in Documentation Comments by @leopardracer in https://github.com/jamesmunns/postcard/pull/239

Fix typo in docstring by @lecanard539 in https://github.com/jamesmunns/postcard/pull/218

Implement Schema and MaxSize for more core types by @max-heller in https://github.com/jamesmunns/postcard/pull/240

Implement Schema and MaxSize for nalgebra::{Quaternion,Unit} by @max-heller in https://github.com/jamesmunns/postcard/pull/242

Fix typos by @kilavvy in https://github.com/jamesmunns/postcard/pull/247

Version bump defmt to 1.x.x by @IamTheCarl in https://github.com/jamesmunns/postcard/pull/234

Add dummy "paste" feature by @jamesmunns in https://github.com/jamesmunns/postcard/pull/249

Update cobs to 0.3.0 by @musicinmybrain in https://github.com/jamesmunns/postcard/pull/226

Update postcard’s dep. on postcard-derive to 0.2 by @musicinmybrain in https://github.com/jamesmunns/postcard/pull/228

Support std::io::Read flavor with minimal temporary buffer by @Calsign in https://github.com/jamesmunns/postcard/pull/212

Release postcard/v1.1.2 by @jamesmunns in https://github.com/jamesmunns/postcard/pull/250

New Contributors

@ChocolateLoverRaj made their first contribution in https://github.com/jamesmunns/postcard/pull/193

@ManevilleF made their first contribution in https://github.com/jamesmunns/postcard/pull/191

@sommd made their first contribution in https://github.com/jamesmunns/postcard/pull/202

@quietlychris made their first contribution in https://github.com/jamesmunns/postcard/pull/215

@Gerharddc made their first contribution in https://github.com/jamesmunns/postcard/pull/222

@Veykril made their first contribution in https://github.com/jamesmunns/postcard/pull/237

@leopardracer made their first contribution in https://github.com/jamesmunns/postcard/pull/239

@lecanard539 made their first contribution in https://github.com/jamesmunns/postcard/pull/218

@kilavvy made their first contribution in https://github.com/jamesmunns/postcard/pull/247

@IamTheCarl made their first contribution in https://github.com/jamesmunns/postcard/pull/234

@musicinmybrain made their first contribution in https://github.com/jamesmunns/postcard/pull/226

@Calsign made their first contribution in https://github.com/jamesmunns/postcard/pull/212

Full Changelog: https://github.com/jamesmunns/postcard/compare/postcard/v1.1.1...postcard/v1.1.2

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Release timeline

40 releases since 2019

Additional notes

This project publishes no release notes. Between postcard/v1.1.1 and postcard/v1.1.2 there were 90 commits, 58 of them substantive:

Add #[postcard(bound = "...")] attribute for derive(Schema)
docs: Add notes on serde attributes
Implement MaxSize for serializable Range structs
Add Range structs to schema
doc
test retrieving schema in #[postcard(bound)] test
Add Schema to PathBuf
Use String as schema, don't display alloc feature in docs
Fix builtins_alloc feature doc-tag
Fix EOF not being handled correctly
Add unit tests
Add key from postcard-rpc
Release postcard-schema v0.2.1
schema hash stability test
restructure schema type hierarchy
update #[derive(Schema)] error referencing postcard::experimental
change DataModelType::Schema hash value
Support std::io::Read flavor with minimal temporary buffer
Rename try_take_n_borrowed back to try_take_n to maintain backwards-compatibility
Remove try_take_n_const

…and 38 more.

1.1.129 Nov 2024

Update to edition 2021 (and clippy fixes) by @barafael in https://github.com/jamesmunns/postcard/pull/169

What's Changed

Update to edition 2021 (and clippy fixes) by @barafael in https://github.com/jamesmunns/postcard/pull/169

Full Changelog: https://github.com/jamesmunns/postcard/compare/postcard/v1.1.0...postcard/v1.1.1

Open source →

Additional notes

This project publishes no release notes. Between postcard/v1.1.0 and postcard/v1.1.1 there were 9 commits, 7 of them substantive:

Fix edition 2021 idioms
Improve flavor doc strings
Remove elidable lifetimes
Explicitly list dep:name in cargo features
Set postcard to edition 2021
Fix minor clippy lints mostly around docs
Clippy suggests adding some lifetime annotations and removing some others

1.1.027 Nov 2024

Corrected invalid link in Serializer docs by @TylerBloom in https://github.com/jamesmunns/postcard/pull/173

What's Changed

Corrected invalid link in Serializer docs by @TylerBloom in https://github.com/jamesmunns/postcard/pull/173
Implement a version of Schema types that are owned by @jamesmunns in https://github.com/jamesmunns/postcard/pull/170
Introduce postcard-schema crate by @jamesmunns in https://github.com/jamesmunns/postcard/pull/176
Fix typo by @rockboynton in https://github.com/jamesmunns/postcard/pull/177
Merge in postcard dyn by @jamesmunns in https://github.com/jamesmunns/postcard/pull/178
Feature gate some tests by @Manishearth in https://github.com/jamesmunns/postcard/pull/184
Upgrade postcard-derive's syn dependency to 2.0 by @max-heller in https://github.com/jamesmunns/postcard/pull/185
Add #[postcard(crate = ...)] attribute for derive(Schema) by @max-heller in https://github.com/jamesmunns/postcard/pull/186
Fix nalgebra schema by @max-heller in https://github.com/jamesmunns/postcard/pull/188
Switch schema name for [T] from "&[T]" to "[T]" by @max-heller in https://github.com/jamesmunns/postcard/pull/187
Make IOReader and EIOReader constructors public by @Spartan2909 in https://github.com/jamesmunns/postcard/pull/190

New Contributors

@TylerBloom made their first contribution in https://github.com/jamesmunns/postcard/pull/173
@rockboynton made their first contribution in https://github.com/jamesmunns/postcard/pull/177
@max-heller made their first contribution in https://github.com/jamesmunns/postcard/pull/185
@Spartan2909 made their first contribution in https://github.com/jamesmunns/postcard/pull/190

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.10...postcard/v1.1.0

Open source →

Additional notes

This project publishes no release notes. Between v1.0.10 and postcard/v1.1.0 there were 36 commits, 26 of them substantive:

Ser mostly works, using serde_json::Value for now
Basic round trip testing
make try_take_varint_usize public for all targets
fix(docs): Corrected invalid link in Serializer docs (#173)
Lean on owned types
Cargo fmt
Stub out schemas for now
Fix tests
Implement a version of Schema types that are owned (#170)
Introduce postcard-schema crate (#176)
Add placeholder readme
fix typo (#177)
Update with released crates
ready to archive
Move to folder so I can do an unrelated merge
Clean up some things to include postcard-dyn
More cleanup
Feature gate some tests
upgrade postcard-derive's syn dependency to 2.0
add #[postcard(crate = ...)] attribute

…and 6 more.

1.0.1021 Aug 2024

Check that target supports atomic pointer operations before defining max size for Arc by @sjudson in https://github.com/jamesmunns/postcard/pull/168

What's Changed

Check that target supports atomic pointer operations before defining max size for Arc by @sjudson in https://github.com/jamesmunns/postcard/pull/168

New Contributors

@sjudson made their first contribution in https://github.com/jamesmunns/postcard/pull/168

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.9...v1.0.10

Open source →

Additional notes

This project publishes no release notes. Between v1.0.9 and v1.0.10 there were 2 commits, 2 of them substantive:

Check that target supports atomic pointer operations before defining max size for Arc (#168)
Prepare for v1.0.10 release

1.0.920 Aug 2024

Update heapless by @luqasz in https://github.com/jamesmunns/postcard/pull/115

What's Changed

#118 Add support for latest embedded-io by @elast0ny in https://github.com/jamesmunns/postcard/pull/123
Update heapless by @luqasz in https://github.com/jamesmunns/postcard/pull/115
Fix Vec pre-alloc panic by @isikkema in https://github.com/jamesmunns/postcard/pull/136
Define MaxSize for Arc and Rc by @carlsverre in https://github.com/jamesmunns/postcard/pull/137
Typo in from_io comment by @smoelius in https://github.com/jamesmunns/postcard/pull/139
Fix schema implementation for slice references by @ia0 in https://github.com/jamesmunns/postcard/pull/142
Fix #89: #[derive(Schema)] for StructVariants by @barafael in https://github.com/jamesmunns/postcard/pull/134
Drop unused const_format dependency by @paolobarbolini in https://github.com/jamesmunns/postcard/pull/133
Remove unnecessary lifetimes of CRC digest by @cdunster in https://github.com/jamesmunns/postcard/pull/129
Fix compilation with alloc and experimental-derive by @ia0 in https://github.com/jamesmunns/postcard/pull/145
Use well-known docsrs cfg for docs.rs by @ia0 in https://github.com/jamesmunns/postcard/pull/146
Add basic continuous integration script by @ia0 in https://github.com/jamesmunns/postcard/pull/148
Fix formatting by @ia0 in https://github.com/jamesmunns/postcard/pull/149
Fix clippy lints by @ia0 in https://github.com/jamesmunns/postcard/pull/150
Fix documentation lints by @ia0 in https://github.com/jamesmunns/postcard/pull/152
Relayout the repo by @jamesmunns in https://github.com/jamesmunns/postcard/pull/151
revert 'Update heapless (#115)' by @Manishearth in https://github.com/jamesmunns/postcard/pull/164
Somethings odd with the import path by @jamesmunns in https://github.com/jamesmunns/postcard/pull/166

New Contributors

@elast0ny made their first contribution in https://github.com/jamesmunns/postcard/pull/123
@luqasz made their first contribution in https://github.com/jamesmunns/postcard/pull/115
@isikkema made their first contribution in https://github.com/jamesmunns/postcard/pull/136
@carlsverre made their first contribution in https://github.com/jamesmunns/postcard/pull/137
@smoelius made their first contribution in https://github.com/jamesmunns/postcard/pull/139
@ia0 made their first contribution in https://github.com/jamesmunns/postcard/pull/142
@barafael made their first contribution in https://github.com/jamesmunns/postcard/pull/134
@paolobarbolini made their first contribution in https://github.com/jamesmunns/postcard/pull/133
@cdunster made their first contribution in https://github.com/jamesmunns/postcard/pull/129
@Manishearth made their first contribution in https://github.com/jamesmunns/postcard/pull/164

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.8...v1.0.9

Open source →

Additional notes

This project publishes no release notes. Between v1.0.8 and v1.0.9 there were 20 commits, 20 of them substantive:

Add support for latest embedded-io (#123)
Update heapless (#115)
Fix Vec pre-alloc panic (#136)
Define MaxSize for Arc and Rc (#137)
Typo in from_io comment (#139)
Fix schema implementation for slice references (#142)
Fix #89: #[derive(Schema)] for StructVariants (#134)
Drop unused const_format dependency (#133)
Remove unnecessary lifetimes of CRC digest (#129)
Fix compilation with alloc and experimental-derive (#145)
Use well-known docsrs cfg for docs.rs (#146)
Add basic continuous integration script (#148)
Fix formatting (#149)
Fix clippy lints (#150)
Fix documentation lints (#152)
Reorganize repository into a single source folder (#151)
revert 'Update heapless (#115)' (#164)
Somethings odd with the import path (#166)
Fix derive path
Update derive dep

1.0.827 Sep 2023

Feat: Add IO traits support by @xgroleau in https://github.com/jamesmunns/postcard/pull/91

What's Changed

Feat: Add IO traits support by @xgroleau in https://github.com/jamesmunns/postcard/pull/91

New Contributors

@xgroleau made their first contribution in https://github.com/jamesmunns/postcard/pull/91

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.7...v1.0.8

Open source →

Additional notes

This project publishes no release notes. Between v1.0.7 and v1.0.8 there were 2 commits, 2 of them substantive:

Feat: Add IO traits support (#91)
Prepare for 1.0.8

1.0.731 Aug 2023

Fix off-by-one in varint size calculation by @Palladinium in https://github.com/jamesmunns/postcard/pull/111

What's Changed

Fix off-by-one in varint size calculation by @Palladinium in https://github.com/jamesmunns/postcard/pull/111
Add specific error for Crc errors by @CBJamo in https://github.com/jamesmunns/postcard/pull/112

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.6...v1.0.7

Open source →

Additional notes

This project publishes no release notes. Between v1.0.6 and v1.0.7 there were 3 commits, 3 of them substantive:

Add specific error for Crc errors. (#112)
Fix off-by-one in varint size calculation (#111)
Prepare for v1.0.7

1.0.619 Jul 2023

Render cfg information on docs.rs by @dtolnay in https://github.com/jamesmunns/postcard/pull/108

What's Changed

Render cfg information on docs.rs by @dtolnay in https://github.com/jamesmunns/postcard/pull/108

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.5...v1.0.6

Open source →

Additional notes

This project publishes no release notes. Between v1.0.5 and v1.0.6 there were 3 commits, 2 of them substantive:

Render cfg information on docs.rs (#108)
Prepare for 1.0.6 release

1.0.518 Jul 2023

improved documentation of the cobs decoding by @gutzchi in https://github.com/jamesmunns/postcard/pull/97

What's Changed

improved documentation of the cobs decoding by @gutzchi in https://github.com/jamesmunns/postcard/pull/97
Fix strict provenance use of pointers by @jamesmunns in https://github.com/jamesmunns/postcard/pull/100
Introduces CRCs by @huntc in https://github.com/jamesmunns/postcard/pull/98
Format with rustfmt to eliminate trailing whitespaces by @dtolnay in https://github.com/jamesmunns/postcard/pull/104
Fix documentation of re-exports that have dedicated doc comment by @dtolnay in https://github.com/jamesmunns/postcard/pull/107

New Contributors

@gutzchi made their first contribution in https://github.com/jamesmunns/postcard/pull/97

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.4...v1.0.5

Open source →

1.0.416 Feb 2023

fix: cobs accumulator out-of-bounds index when data is 1 byte too long by @jedrzejboczar in https://github.com/jamesmunns/postcard/pull/90

What's Changed

fix: cobs accumulator out-of-bounds index when data is 1 byte too long by @jedrzejboczar in https://github.com/jamesmunns/postcard/pull/90

New Contributors

@jedrzejboczar made their first contribution in https://github.com/jamesmunns/postcard/pull/90

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.3...v1.0.4

Open source →

1.0.316 Feb 2023

Add a link to doc.rs documentation in README by @benbrittain in https://github.com/jamesmunns/postcard/pull/72

What's Changed

Add a link to doc.rs documentation in README by @benbrittain in https://github.com/jamesmunns/postcard/pull/72
Add feed_ref to cobs_accumulator by @CaptainMaso in https://github.com/jamesmunns/postcard/pull/70
Add support for 16-bit and 8-bit architectures by @iFreilicht in https://github.com/jamesmunns/postcard/pull/64
Make fixints usable through serde field attributes instead of wrappers by @lachlansneff-parallel in https://github.com/jamesmunns/postcard/pull/69
Add a Schema impl for std::string::String with the use-std feature and for alloc::string::String with alloc by @zRedShift in https://github.com/jamesmunns/postcard/pull/76
Bump postcard-derive version by @benbrittain in https://github.com/jamesmunns/postcard/pull/74
Optimize varint decode by @bugadani in https://github.com/jamesmunns/postcard/pull/62
Fix typos & encoding example in wire doc by @raphlinus in https://github.com/jamesmunns/postcard/pull/83
feat: add function for computing the postcard serialized size of a value. by @dignifiedquire in https://github.com/jamesmunns/postcard/pull/86
PhantomData's T doesn't need MaxSize impl by @k3d3 in https://github.com/jamesmunns/postcard/pull/87

New Contributors

@CaptainMaso made their first contribution in https://github.com/jamesmunns/postcard/pull/70
@iFreilicht made their first contribution in https://github.com/jamesmunns/postcard/pull/64
@zRedShift made their first contribution in https://github.com/jamesmunns/postcard/pull/76
@raphlinus made their first contribution in https://github.com/jamesmunns/postcard/pull/83
@dignifiedquire made their first contribution in https://github.com/jamesmunns/postcard/pull/86
@k3d3 made their first contribution in https://github.com/jamesmunns/postcard/pull/87

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.2...v1.0.3

Open source →

1.0.216 Aug 2022

Fix Schema proc_macro to export through public experimental module. by @benbrittain in https://github.com/jamesmunns/postcard/pull/73

What's Changed

Fix Schema proc_macro to export through public experimental module. by @benbrittain in https://github.com/jamesmunns/postcard/pull/73

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.1...v1.0.2

Open source →

1.0.115 Jul 2022

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.0...v1.0.1

Full Changelog: https://github.com/jamesmunns/postcard/compare/v1.0.0...v1.0.1

Open source →

1.0.020 Jun 2022Withdrawn

This is the first stable 1.0.0 releases for Postcard. 🎉 !

What's Changed

Clarify the non-self-describing nature of postcard by @huntc in https://github.com/jamesmunns/postcard/pull/58
Fixint wrapper type. by @lachlansneff-parallel in https://github.com/jamesmunns/postcard/pull/57
Optimize Varint encoding by @bugadani in https://github.com/jamesmunns/postcard/pull/60
Add a MaxSize trait and derive macro by @lachlansneff in https://github.com/jamesmunns/postcard/pull/54

New Contributors

@lachlansneff made their first contribution in https://github.com/jamesmunns/postcard/pull/54

Full Changelog: https://github.com/jamesmunns/postcard/compare/v0.7.3...v1.0.0

Open source →

1.0.0-alpha.420 Jun 2022Pre-release