Multipaz

This repository contains libraries and applications for working with real-world identity. The initial focus for this work was mdoc/mDL according to ISO/IEC 18013-5:2021 and related standards but the current scope also include other credential formats and presentment protocols.

Multipaz Libraries

The project provides libraries written in Kotlin Multiplatform:

• multipaz provides the core building blocks it works on Android, iOS, and in server-side environments. The library includes support for ISO mdoc and IETF SD-JWT VC credential formats and also implements proximity presentment using ISO/IEC 18013-5:2021 (for ISO mdoc credentials) and presentment to applications using the W3C Digital Credentials API according to ISO/IEC 18013-7:2025 and OpenID4VP 1.0.
• multipaz-compose provides rich UI elements to be used in Compose applications.
• multipaz-doctypes contains known credential document types (for example ISO/IEC 18013-5:2021 mDL and EU PID) along with human-readable descriptions of claims / data elements, sample data, and sample requests. This is packaged separately from the core multipaz library because its size is non-negligible and not all applications need this or they may bring their own.
• multipaz-longfellow bundles the Google Longfellow-ZK library and integrates with the core multipaz for Zero-Knowledge Proofs according to latest available ISO/IEC 18013-5 Second Edition draft.
• multipaz-swift contains Swift and SwiftUI functionality to easier use Multipaz in Swift applications on iOS.

Command-line tool

A command-line tool multipazctl is also included which can be used to generate ISO/IEC 18013-5:2021 IACA certificates among other things. Use ./gradlew --quiet runMultipazCtl --args "help" for documentation on supported verbs and options. To set up a wrapper, first build the fat jar

$ ./gradlew multipazctl:buildFatJar

then create a wrapper like this

#!/bin/sh
MAIN_CLASS="org.multipaz.multipazctl.MultipazCtl"
CLASSPATH="/Users/davidz/StudioProjects/identity-credential/multipazctl/build/libs/multipazctl-all.jar"
JVM_OPTS="-Xms256m -Xmx512m"
exec java $JVM_OPTS -cp "$CLASSPATH" "$MAIN_CLASS" "$@"

in e.g. ~/bin/multipazctl adjusting paths as needed. With this you can now invoke multipazctl like any other system tool.

Library releases, Versioning, and Stability

Libraries are released on GMaven with a two-month cadence and Semantic Versioning is used. At this time we're in pre-1.0 territory but we expect to hit 1.0 around early 2026.

We are also making Multipaz available as a Swift package which includes an the multipaz, multipaz-doctypes, multipaz-doctypes, multipaz-longfellow, and multipaz-swift libraries. This is built using SKIE. Be careful relying on this as Swift/Kotlin interop technology might change in the near future.

At this point both API interfaces and data stored on disk is subject to change but we expect to provide stability guarantees post 1.0. We only expect minor changes for example conversion from ByteArray to ByteString and similar things.

Getting involved

We have resources for people already involved and people wishing to contribute to the Multipaz project

• CONTRIBUTING.md for how to get involved with the project and send PRs.
• CODE-OF-CONDUCT.md for the policies and rules around collaboration.
• CODING-STYLE.md for guidelines on writing code to be included in the project.
• TESTING.md explains our approach to unit and manual testing.
• DEVELOPER-ENVIRONMENT.md for how to set up your system for building Multipaz.

Note: If you're just looking to use the Multipaz libraries you do not need to build the entire Multipaz project from source. Instead, just use our released libraries, see the next section for an example of this.

Examples / Samples

For a fully-fledged mDL wallet, our current answer is to use the samples/testapp module which works on both Android and iOS. This application is intended for developers and as such has a lot of options and settings. It's intended to exercise all code in the libraries. Prebuilt APKs are available from https://apps.multipaz.org.

For a fully-featured proximity reader app using Multipaz, see MpzIdentityReader. Prebuilt APKs are available from https://apps.multipaz.org.

For an over-the-Internet verifier supporting OpenID4VP (both W3C DC API and URI schemes) and ISO/IEC 18013-7 Annex C see https://verifier.multipaz.org.

To see how to use the Multipaz in a 3rd party project, see https://github.com/openwallet-foundation/multipaz-samples/ which includes a number of samples for different platforms.

Developer Resources

developer.multipaz.org is a comprehensive resource for developers. The entire developer website is open source and contributions are welcome!

Documentation

• Getting Started: Provides foundational knowledge for new users.
• API Reference: Comprehensive documentation for every API endpoint, providing thorough understanding of the available functionalities.
• Codelabs: Guided tutorials on key identity credential concepts, along with sample apps that provide tangible examples to accelerate development.
• Showcase Apps: Real-world applications built leveraging the Multipaz framework.

Applications

• Android Apps
• Web Verifier App
• Issuer Portal
• Identity Reader Backend

Community & Contribution

• Contributing Guide
• Website Contribution Guide
• Blog
• Discord

Note

This is not an official or supported Google product.