aws/jsii

jsii allows code in any language to naturally interact with JavaScript classes. It is the technology that enables the AWS Cloud Development Kit to deliver polyglot libraries from a single codebase!

TypeScript

2,869

3,661 commits

updated Oct 12, 2026

aws.github.io/jsii

See the code

README

Overview

jsii allows code in any language to naturally interact with JavaScript classes. It is the technology that enables the AWS Cloud Development Kit to deliver polyglot libraries from a single codebase!

A class library written in TypeScript can be used in projects authored in TypeScript or Javascript (as usual), but also in Python, Java, C# (and other languages from the .NET family), ...

❓ Documentation

Head over to our documentation website!

The jsii toolchain is spread out on multiple repositories:

aws/jsii-compiler is where the jsii compiler is maintained
aws/jsii-rosetta is where the jsii-rosetta sample code transliteration tool is maintained
aws/jsii is where the rest of the toolchain is maintained, including:
- The jsii runtime libraries for the supported jsii target languages
- @jsii/spec, the package that defines the .jsii assembly specification
- jsii-pacmak, the bindings generator for jsii packages
- jsii-reflect, a higher-level way to process .jsii assemblies
- jsii-config, an interactive tool to help configure your jsii package

📖 Blog Posts

Here's a collection of blog posts (in chronological order) related to jsii:

2020-01-11: How to Create CDK Constructs, by Matthew Bonig
2020-05-27: Generate Python, Java, and .NET software libraries from a TypeScript source, by Hari Pachuveetil
2020-12-23: How the jsii open source framework meets developers where they are, by Romain Marcadier

ℹ️ If you wrote blog posts about jsii and would like to have them referenced here, do not hesitate to file a pull request to add the links here!

⚙️ Contributing

See CONTRIBUTING.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

_{AWS CDK Automation} 🚧 👀	_{Aaron Costley} 🐛 💻 🤔 👀	_{Abdallah Hodieb} 🐛	_{Adam Ruka} 🐛 💻 🚧 👀	_{Adrian Dimech} 💻	_{Adrian Hesketh} 💻	_{Alex Pulver} 🐛
_{Amir Szekely} 🚧	_{Andi Pabst} 🐛	_{Andrew Wason} 🐛 💻	_{André Fontenele} 💻	_{Andy Slezak} 💻	_{Ansgar Mertens} 🚧 💻 🐛	_{Anshul Guleria} 🤔
_{Ari Palo} 🤔	_{Armaan Tobaccowalla} 🐛	_{Bartłomiej Jurek} 🐛	_{Ben Bridts} 📖	_{Ben Chaimberg} 📖	_{Ben Farr} 📖	_{Ben Walters} 🤔
_{Benjamin Macher} 📖	_{Benjamin Maizels} 💻 👀	_{Bervianto Leo Pratama} 🚧	_{Bill Cauchois} 🤔	_{Bradley Sherman} 💻	_{Brecht Verhoeve} 🤔	_{Breland Miley} 💻
_CaerusKaru 💻 🚧	_{Calvin Combs} 💻 👀	_{Camilo Bermúdez} 🐛	_{Campion Fellin} 💻	_{Carter Van Deuren} 🐛	_{Chris Garvis} 📖	_{Christian Moore} 🐛
_{Christophe Vico} 🐛	_{Christopher Currie} 💻 🤔	_{Christopher Rybicki} 📖 🐛 💻	_{Colin Francis} 🚧	_{CommanderRoot} 💻	_{Cory Hall} 🐛	_{Cristian Măgherușan-Stanciu} 🐛
_{CyrusNajmabadi} 🐛 🤔	_{Damian Silbergleith} 💻 🐛	_{Daniel Dinu} 🐛 💻	_{Daniel Schmidt} 🐛 💻	_{Daniel Schroeder} 🐛 💻 📖 🤔 🚧	_{Dave Slotnick} 🐛	_{David Bell} 💻
_{Donald Stufft} 🐛 💻 🤔 👀	_{Dongie Agnir} 💻 👀	_{Eduardo Rabelo} 📖	_{Eduardo Sena S. Rosa} 🐛	_{Elad Ben-Israel} 🐛 💻 🤔 🚧 👀 📢	_{Eli Polonsky} 🐛 💻 🤔 🚧 👀	_{Eric Carboni} 📖
_{Eric Z. Beard} 📆	_{Erik Karlsson} 🐛	_{Eugene Kozlov} 💻	_{Fabio Gentile} 🐛	_{Florian Eitel} 🤔	_{Glib Shpychka} 🐛	_{Graham Lea} 🤔 👀
_{Greg Lucas} 💻	_{Hamza Assyad} 🐛 💻 🤔 👀	_{Hari Pachuveetil} 📝 📖	_{Hirotaka Tagawa / wafuwafu13} 💻	_{Hsing-Hui Hsu} 💻 📖 🤔 👀	_{Huy Phan (Harry)} 💻	_{Ikko Ashimine} 📖
_James 🐛 💻	_{James Kelley} 🐛	_{James Mead} 💻	_{James Siri} 💻 🚧	_{Jason Del Ponte} 🤔 👀	_{Jason Fulghum} 🤔 📆 👀	_{Jeff Malins} 💻
_{Jerry Kindall} 📖 🤔	_{Jimmy Gaussen} 🤔	_{Johannes Weber} 📖	_{John Pantzlaff} 💻	_{Jon Day} 💻	_{Jon Steinich} 🐛 🤔 💻	_{Joseph Lawson} 👀
_{Joseph Martin} 🐛	_Junix 🐛	_{Justin Frahm} 🐛	_{Justin Taylor} 🐛	_{Kaizen Conroy} 💻 🐛	_{Kaizen Conroy} 💻	_{Kaushik Borra} 🐛
_{Kendra Neil} 🚧	_{Knut O. Hellan} 🐛	_{Kyle Thomson} 💻 👀	_{Leandro Padua} 🐛	_{Liang Zhou} 🐛 💻	_{Madeline Kusters} 💻 🐛	_{Maja S Bratseth} 🐛
_{Marcos Diez} 🐛	_{Mark Nielsen} 💻	_{Matthew Bonig} 🐛 📝	_{Matthew Pirocchi} 💻 🤔 👀	_{Meng Xin Zhu} 🐛	_{Michael Neil} 🚧	_{Mike Lane} 🐛
_{Mitch Garnaat} 🐛 💻 🤔 👀	_{Mitchell Valine} 🐛 💻 🤔 🚧 👀	_{Mohamad Soufan} 📖	_{Mohamed Elasmar} 💻	_{Momo Kornher} 💻	_{Mykola Mogylenko} 🐛	_Naumel 👀
_{Neta Nir} 💻 🤔 🚧 👀	_{Nick Lynch} 🐛 💻 🚧 👀	_{Niranjan Jayakar} 🐛 💻 🤔 🚧 👀	_{Noah Litov} 💻 🚧 👀	_{Otavio Macedo} 💻 🐛	_{PIDZ - Bart} 🤔	_{Pahud Hsieh} 💻
_{Peter Woodworth} 🚧	_{Petr Kacer} 🐛	_{Petra Barus} 💻	_{Philip Cali} 🤔	_{Quentin Loos} 🤔	_Raphael 🐛	_{Richard H Boyd} 🐛
_{Rico Huijbers} 🐛 💻 🤔 🚧 👀	_{Romain Marcadier} 🐛 💻 🎨 🤔 🚧 👀 📝	_{Ryan Parker} 💻	_{SADIK KUZU} 👀	_SK 🤔	_{Sam Fink} 💻 👀	_{Sam Goodwin} 👀
_{Sebastian Korfmann} 🐛 💻 🤔	_{Sepehr Laal} 🐛	_{Shailja Khurana} 🚧	_{Shane Witbeck} 🤔	_{Shiv Lakshminarayan} 💻 🚧 👀	_Somaya 💻 🤔 🚧 👀	_{Stephen Kuenzli} 📖
_{Takahiro Sugiura} 📖	_{The Gitter Badger} 💻 🚧	_{Thomas Poignant} 🐛	_{Thomas Steinbach} 🐛	_{Thorsten Hoeger} 💻	_{Tim Wagner} 🐛 🤔	_{Timothy Jones} 🐛
_{Tobias Lidskog} 💻	_{Tom Bonner} 🐛	_{Tom Keller} 🚧	_{Ty Coghlan} 🐛	_{Tyler van Hensbergen} 🤔	_{Vinayak Kukreja} 💻	_{Vlad Hrybok} 🐛
_{Vladimir Shchur} 🐛	_{Will Bender} 🐛	_{Yan Zhulanow} 💻	_Yathi 💻	_{Yigong Liu} 🐛 🤔	_{Zach Bienenfeld} 🐛	_ajnarang 🤔
_andyan 📖	_aniljava 💻	_{arnogeurts-sqills} 🐛 💻	_cn-cit 🐛	_deccy-mcc 🐛	_{dependabot-preview[bot]} 🐛 🚧	_{dependabot[bot]} 🚧
_dheffx 🐛	_gregswdl 🐛	_guyroberts21 📖	_{mattBrzezinski} 📖	_mergify 🚧	_mergify[bot] 🚧	_nathannaveen 🚧
_seiyashima42 🐛 💻 📖	_sullis 💻	_vaneek 🐛	_wendysophie 🐛	_ysuzuki19 📖

This project follows the all-contributors specification. Contributions of any kind welcome!

⚖️ License

jsii is distributed under the Apache License, Version 2.0.

See LICENSE and NOTICE for more information.

aws

cross-language

hacktoberfest

node

typescript

Project health

Overall

7.1/10

Maintained

10/10

Code review

10/10

OpenSSF Scorecard

Significant stargazers

(top 24 of 38)

Yordis Prieto

276 followers · starred Dec 2021

R0CKSTAR

468 followers · starred Jul 2025

Huan Li

2,359 followers · starred Dec 2021

Michael Bridgen

359 followers · starred Nov 2019

Similar repos

aws/aws-cdk

The AWS Cloud Development Kit is a framework for defining cloud infrastructure in code

12,929

same org

aws/aws-pdk

The AWS PDK provides building blocks for common patterns together with development tools to manage…

452

same org

kalaiser/awesome-cdk

A collection of awesome things related to the AWS Cloud Development Kit (CDK)

2,124

aws-samples/aws-cdk-examples

Example projects using the AWS CDK

5,643

projen/projen

Rapidly build modern applications with advanced configuration management

2,958

codesandbox/codesandbox-client

An online IDE for rapid web development

13,651

bytecodealliance/jco

JavaScript toolchain for working with WebAssembly Components

1,010

codemod-com/codemod

The CLI for codemods: scaffold, share, and run multi-step transformations of any size. First-class…

1,108

aws/jsii

jsii allows code in any language to naturally interact with JavaScript classes. It is the technology that enables the AWS Cloud Development Kit to deliver polyglot libraries from a single codebase!

TypeScript

2,869

3,661 commits

updated Oct 12, 2026

aws.github.io/jsii

See the code

README

Overview

jsii allows code in any language to naturally interact with JavaScript classes. It is the technology that enables the AWS Cloud Development Kit to deliver polyglot libraries from a single codebase!

❓ Documentation

Head over to our documentation website!

The jsii toolchain is spread out on multiple repositories:

aws/jsii-compiler is where the jsii compiler is maintained
aws/jsii-rosetta is where the jsii-rosetta sample code transliteration tool is maintained
aws/jsii is where the rest of the toolchain is maintained, including:
- The jsii runtime libraries for the supported jsii target languages
- @jsii/spec, the package that defines the .jsii assembly specification
- jsii-pacmak, the bindings generator for jsii packages
- jsii-reflect, a higher-level way to process .jsii assemblies
- jsii-config, an interactive tool to help configure your jsii package

📖 Blog Posts

Here's a collection of blog posts (in chronological order) related to jsii:

2020-01-11: How to Create CDK Constructs, by Matthew Bonig
2020-05-27: Generate Python, Java, and .NET software libraries from a TypeScript source, by Hari Pachuveetil
2020-12-23: How the jsii open source framework meets developers where they are, by Romain Marcadier

ℹ️ If you wrote blog posts about jsii and would like to have them referenced here, do not hesitate to file a pull request to add the links here!

⚙️ Contributing

See CONTRIBUTING.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

_{AWS CDK Automation} 🚧 👀	_{Aaron Costley} 🐛 💻 🤔 👀	_{Abdallah Hodieb} 🐛	_{Adam Ruka} 🐛 💻 🚧 👀	_{Adrian Dimech} 💻	_{Adrian Hesketh} 💻	_{Alex Pulver} 🐛
_{Amir Szekely} 🚧	_{Andi Pabst} 🐛	_{Andrew Wason} 🐛 💻	_{André Fontenele} 💻	_{Andy Slezak} 💻	_{Ansgar Mertens} 🚧 💻 🐛	_{Anshul Guleria} 🤔
_{Ari Palo} 🤔	_{Armaan Tobaccowalla} 🐛	_{Bartłomiej Jurek} 🐛	_{Ben Bridts} 📖	_{Ben Chaimberg} 📖	_{Ben Farr} 📖	_{Ben Walters} 🤔
_{Benjamin Macher} 📖	_{Benjamin Maizels} 💻 👀	_{Bervianto Leo Pratama} 🚧	_{Bill Cauchois} 🤔	_{Bradley Sherman} 💻	_{Brecht Verhoeve} 🤔	_{Breland Miley} 💻
_CaerusKaru 💻 🚧	_{Calvin Combs} 💻 👀	_{Camilo Bermúdez} 🐛	_{Campion Fellin} 💻	_{Carter Van Deuren} 🐛	_{Chris Garvis} 📖	_{Christian Moore} 🐛
_{Christophe Vico} 🐛	_{Christopher Currie} 💻 🤔	_{Christopher Rybicki} 📖 🐛 💻	_{Colin Francis} 🚧	_{CommanderRoot} 💻	_{Cory Hall} 🐛	_{Cristian Măgherușan-Stanciu} 🐛
_{CyrusNajmabadi} 🐛 🤔	_{Damian Silbergleith} 💻 🐛	_{Daniel Dinu} 🐛 💻	_{Daniel Schmidt} 🐛 💻	_{Daniel Schroeder} 🐛 💻 📖 🤔 🚧	_{Dave Slotnick} 🐛	_{David Bell} 💻
_{Donald Stufft} 🐛 💻 🤔 👀	_{Dongie Agnir} 💻 👀	_{Eduardo Rabelo} 📖	_{Eduardo Sena S. Rosa} 🐛	_{Elad Ben-Israel} 🐛 💻 🤔 🚧 👀 📢	_{Eli Polonsky} 🐛 💻 🤔 🚧 👀	_{Eric Carboni} 📖
_{Eric Z. Beard} 📆	_{Erik Karlsson} 🐛	_{Eugene Kozlov} 💻	_{Fabio Gentile} 🐛	_{Florian Eitel} 🤔	_{Glib Shpychka} 🐛	_{Graham Lea} 🤔 👀
_{Greg Lucas} 💻	_{Hamza Assyad} 🐛 💻 🤔 👀	_{Hari Pachuveetil} 📝 📖	_{Hirotaka Tagawa / wafuwafu13} 💻	_{Hsing-Hui Hsu} 💻 📖 🤔 👀	_{Huy Phan (Harry)} 💻	_{Ikko Ashimine} 📖
_James 🐛 💻	_{James Kelley} 🐛	_{James Mead} 💻	_{James Siri} 💻 🚧	_{Jason Del Ponte} 🤔 👀	_{Jason Fulghum} 🤔 📆 👀	_{Jeff Malins} 💻
_{Jerry Kindall} 📖 🤔	_{Jimmy Gaussen} 🤔	_{Johannes Weber} 📖	_{John Pantzlaff} 💻	_{Jon Day} 💻	_{Jon Steinich} 🐛 🤔 💻	_{Joseph Lawson} 👀
_{Joseph Martin} 🐛	_Junix 🐛	_{Justin Frahm} 🐛	_{Justin Taylor} 🐛	_{Kaizen Conroy} 💻 🐛	_{Kaizen Conroy} 💻	_{Kaushik Borra} 🐛
_{Kendra Neil} 🚧	_{Knut O. Hellan} 🐛	_{Kyle Thomson} 💻 👀	_{Leandro Padua} 🐛	_{Liang Zhou} 🐛 💻	_{Madeline Kusters} 💻 🐛	_{Maja S Bratseth} 🐛
_{Marcos Diez} 🐛	_{Mark Nielsen} 💻	_{Matthew Bonig} 🐛 📝	_{Matthew Pirocchi} 💻 🤔 👀	_{Meng Xin Zhu} 🐛	_{Michael Neil} 🚧	_{Mike Lane} 🐛
_{Mitch Garnaat} 🐛 💻 🤔 👀	_{Mitchell Valine} 🐛 💻 🤔 🚧 👀	_{Mohamad Soufan} 📖	_{Mohamed Elasmar} 💻	_{Momo Kornher} 💻	_{Mykola Mogylenko} 🐛	_Naumel 👀
_{Neta Nir} 💻 🤔 🚧 👀	_{Nick Lynch} 🐛 💻 🚧 👀	_{Niranjan Jayakar} 🐛 💻 🤔 🚧 👀	_{Noah Litov} 💻 🚧 👀	_{Otavio Macedo} 💻 🐛	_{PIDZ - Bart} 🤔	_{Pahud Hsieh} 💻
_{Peter Woodworth} 🚧	_{Petr Kacer} 🐛	_{Petra Barus} 💻	_{Philip Cali} 🤔	_{Quentin Loos} 🤔	_Raphael 🐛	_{Richard H Boyd} 🐛
_{Rico Huijbers} 🐛 💻 🤔 🚧 👀	_{Romain Marcadier} 🐛 💻 🎨 🤔 🚧 👀 📝	_{Ryan Parker} 💻	_{SADIK KUZU} 👀	_SK 🤔	_{Sam Fink} 💻 👀	_{Sam Goodwin} 👀
_{Sebastian Korfmann} 🐛 💻 🤔	_{Sepehr Laal} 🐛	_{Shailja Khurana} 🚧	_{Shane Witbeck} 🤔	_{Shiv Lakshminarayan} 💻 🚧 👀	_Somaya 💻 🤔 🚧 👀	_{Stephen Kuenzli} 📖
_{Takahiro Sugiura} 📖	_{The Gitter Badger} 💻 🚧	_{Thomas Poignant} 🐛	_{Thomas Steinbach} 🐛	_{Thorsten Hoeger} 💻	_{Tim Wagner} 🐛 🤔	_{Timothy Jones} 🐛
_{Tobias Lidskog} 💻	_{Tom Bonner} 🐛	_{Tom Keller} 🚧	_{Ty Coghlan} 🐛	_{Tyler van Hensbergen} 🤔	_{Vinayak Kukreja} 💻	_{Vlad Hrybok} 🐛
_{Vladimir Shchur} 🐛	_{Will Bender} 🐛	_{Yan Zhulanow} 💻	_Yathi 💻	_{Yigong Liu} 🐛 🤔	_{Zach Bienenfeld} 🐛	_ajnarang 🤔
_andyan 📖	_aniljava 💻	_{arnogeurts-sqills} 🐛 💻	_cn-cit 🐛	_deccy-mcc 🐛	_{dependabot-preview[bot]} 🐛 🚧	_{dependabot[bot]} 🚧
_dheffx 🐛	_gregswdl 🐛	_guyroberts21 📖	_{mattBrzezinski} 📖	_mergify 🚧	_mergify[bot] 🚧	_nathannaveen 🚧
_seiyashima42 🐛 💻 📖	_sullis 💻	_vaneek 🐛	_wendysophie 🐛	_ysuzuki19 📖

This project follows the all-contributors specification. Contributions of any kind welcome!

⚖️ License

jsii is distributed under the Apache License, Version 2.0.

See LICENSE and NOTICE for more information.

aws

cross-language

hacktoberfest

node

typescript

Project health

Overall

7.1/10

Maintained

10/10

Code review

10/10

OpenSSF Scorecard

Significant stargazers

(top 24 of 38)

Yordis Prieto

276 followers · starred Dec 2021

R0CKSTAR

468 followers · starred Jul 2025

Huan Li

2,359 followers · starred Dec 2021

Michael Bridgen

359 followers · starred Nov 2019

Similar repos

aws/aws-cdk

The AWS Cloud Development Kit is a framework for defining cloud infrastructure in code

12,929

same org

aws/aws-pdk

The AWS PDK provides building blocks for common patterns together with development tools to manage…

452

same org

kalaiser/awesome-cdk

A collection of awesome things related to the AWS Cloud Development Kit (CDK)

2,124

aws-samples/aws-cdk-examples

Example projects using the AWS CDK

5,643

projen/projen

Rapidly build modern applications with advanced configuration management

2,958

codesandbox/codesandbox-client

An online IDE for rapid web development

13,651

bytecodealliance/jco

JavaScript toolchain for working with WebAssembly Components

1,010

codemod-com/codemod

The CLI for codemods: scaffold, share, and run multi-step transformations of any size. First-class…

1,108