App stores#

We are also in the process of listing Credible on the iOS TestFlight and Android Play Beta programs, and eventually their respective app marketplaces plus F-Droid.

Common Dependencies#

To manually build Credible for either Android or iOS, you will need to install the following dependencies (instructions follow):

  • Rust
  • Java 7 or higher
  • Flutter (dev channel)
  • DIDKit/SSI
  • wasm-pack (WEB)
  • binaryen (WEB and targeting ASM.js)


It is recommended to use rustup to manage your Rust installation.


On Ubuntu you could run:

# apt update
# apt install openjdk-8-jdk

For more information, please refer to the documentation of your favorite flavour of Java and your operating system/package manager.


Please follow the official instalation instructions available here to install Flutter, don't forget to also install the build dependencies for the platform you will be building (Android SDK/NDK, Xcode, etc).

We currently only support build this project using the dev channel of Flutter.

To change your installation to the dev channel, please execute the following command:

$ flutter channel dev
$ flutter upgrade

To confirm that everything is setup correctly, please run the following command and resolve any issues that arise before proceeding to the next steps.

$ flutter doctor

wasm-pack (Required for both WEB targets)#

The wasm-pack cannot yet be compiled from For now, to build the WASM target you will need wasm-pack, the fastest way is to fetch the script from github and run it in the credible root directory:

$ curl -sSf | sh


To build Credible for WEB using ASM.js you will need binaryen, which allows the conversion of DIDKit WASM to ASM.js. This is necessary in context where WASM support is not available and DIDKit needs to run in pure Javascript. More detailed instructions on how to build binaryen can be found here.

If you are in a UNIX-like distribution you just have to clone the repo and build, we recommend cloning into your ${HOME}, to avoid having to specify the ${BINARYEN_ROOT} variable:

$ git clone ~/binaryen
$ cd ~/binaryen
$ cmake . && make

Not that binaryen support for OS X and Windows is still limited, so it is highly recommended to build it in a linux shell on OS X and on WSL2 in Windows. For instructions on building it natively in Windows, see the binaryen FAQ on github.

DIDKit and SSI#

This project also depends on two other Spruce projects, DIDKit and SSI.

These projects are all configured to work with relative paths by default, so it is recommended to clone them all as subdirectories of the same root directory, for example $HOME/spruceid/didkit $HOME/spruceid/ssi $HOME/spruceid/credible $HOME/spruceid/treehouse etc

Target-Specific Dependencies#

Android Dependencies#

To build Credible for Android, you will require both the Android SDK and NDK.

These two dependencies can be easily obtained with Android Studio, which install further dependencies upon first being opened after installation. Installing the appropriate Android NDK (often not the newest) in Android Studio can be accomplished by going to Settings > Appearance & Behavior > System Settings > Android SDK and selecting to install the "NDK (Side by Side)". An alternative method of installing SDK and NDK without Android Studio can be found in the optional script included here.

If your Android SDK doesn't live at $HOME/Android/Sdk you will need to set ANDROID_SDK_ROOT like so:

$ export ANDROID_SDK_ROOT=/path/to/Android/Sdk

Note: Some users have experienced difficulties with expected cross-compilation artefacts missing from the newest NDK, which is downloaded by default in the installation process. If you experience errors of this kind, you may have to manually downgrade or install multiple NDK versions as [shown here])(img/ndk_downgrade.png) in the Android Studio installer (screengrabbed from an Ubuntu installation). Alternately, running all or parts of the script may be helpful.

If your build-tools and/or NDK live in different locations than the default ones inside /SDK/, or if you want to specify a specific NDK or build-tools version, you can manually configure the following two environment variables:

$ export ANDROID_TOOLS=/path/to/SDK/build-tools/XX.X.X/
$ export ANDROID_NDK_HOME=/path/to/SDK/ndk/XX.X.XXXXX/


iOS Dependencies#

To build Credible for iOS you will need to install CocoaPods, which can be done with Homebrew on MacOS, WSL2, or Linux-based systems. You will also need XCode, which is not available for WSL2 or Linux systems; it is currently possible but not recommended to install XCode in those build environments.

$ sudo apt install linuxbrew-wrapper
$ brew install cocoapods

Web Dependencies#

To build Credible for WASM, you will need the Node.JS and its package manager, npm to be installed:

$ sudo apt install nodejs
$ sudo apt install npm

Note: in some environments, such as Ubuntu 18.04, npm may not automatically install a new enough version for our makefile to execute succesfully; overriding it with npm's internal commands may be necessary.

Building DIDKit for different targets#


To build DIDKit for the Android targets, you will go to the root of DIDKit and run:

$ make -C lib install-rustup-android
$ make -C lib ../target/test/java.stamp
$ make -C lib ../target/test/aar.stamp
$ make -C lib ../target/test/flutter.stamp
$ cargo build

This may take some time as it compiles the entire project for multiple targets

Android APK#

$ flutter build apk --no-sound-null-safety

Android App Bundle#

$ flutter build appbundle --no-sound-null-safety


To build DIDKit for the iOS targets, you wGo to the root of DIDKit and run :

$ make -C lib install-rustup-ios
$ make -C lib ../target/test/ios.stamp
$ cargo build

Web using WASM#

$ make -C lib ../target/test/wasm.stamp

Web using ASM.js#

If you have installed bynarien somewhere other than $HOME, you will have to set BYNARIEN_ROOT as shown below, otherwise, just run the make command.

$ export BINARYEN_ROOT=/path/to/binaryen
$ make -C lib ../target/test/asmjs.stamp

Building Credible#

You are now ready to build or run Credible.

Run on emulator#

If you want to run the project on your connected device, you can use:

$ flutter run --no-sound-null-safety

Run on browser#

If you want to run the project on your browser, you can use:

$ flutter run --no-sound-null-safety -d chrome --csp --release

Otherwise, Flutter allows us to build many artifacts for Android, iOS and WEB, below you can find the most common and useful commands, all of which you should run from the root of Credible.

iOS .app for Simulator#

$ flutter build ios --no-sound-null-safety --no-codesign --simulator

iOS .app for Devices#

$ flutter build ios --no-sound-null-safety --no-codesign


$ flutter build ipa --no-sound-null-safety


$ flutter build web \
--no-sound-null-safety \
--csp \

If you don't have support for WASM, you'll probably need to provide your own canvaskit dependency without WASM as well as DIDKit, to do that you need to specify the FLUTTER_WEB_CANVASKIT_URL in the build command like below.

$ flutter build web \
--no-sound-null-safety \
--csp \
--dart-define=FLUTTER_WEB_CANVASKIT_URL=vendor/ \

For more details about any of these commands you can run

$ flutter build $SUBCOMMAND --help

Note about nullsafety#

While we are ready to migrate to Dart with nullsafety, a couple of the dependencies of the project are still lagging behind, so we need to add --no-sound-null-safely to both run and build commands for the time being.

Note about canvaskit#

Since by default canvaskit comes in a WASM build, in order to the ASM.js be fully supported canvaskit was manually built for this target.

A prebuilt canvaskit is already included in the Credible web folder. If you want to build it by yourself, however, follow these steps:

git clone --depth 1 --branch canvaskit/0.22.0
cd skia
python2 tools/git-sync-deps
  • Modify build script modules/canvaskit/
diff --git a/modules/canvaskit/ b/modules/canvaskit/
index 6ba58bfae9..51f0297eb6 100755
--- a/modules/canvaskit/
+++ b/modules/canvaskit/
@@ -397,6 +397,7 @@ EMCC_DEBUG=1 ${EMCXX} \
- -s WASM=1 \
+ -s WASM=0 \
-o $BUILD_DIR/canvaskit.js
  • Build canvaskit
$ cd modules/canvaskit
$ make debug
  • Replace this line on $SKIA/modules/canvaskit/canvaskit/bin/canvaskit.js
< var isNode = !(new Function('try {return this===window;}catch(e){ return false;}')());
> var isNode = false;
  • Copy $SKIA/modules/canvaskit/canvaskit/bin/canvaskit.js to $CREDIBLE/web/vendor/

  • Build Credible as described above.


Build Environment Problems#

If you encounter any errors in the build process described here, please first try clean builds of the projects listed.

For instance, on Flutter, you can delete build files to start over by running:

$ flutter clean

Also, reviewing the script line by line or even rerunning it line by line may be helpful.

Opaque Makefile error messages#

  • NPM may through an opaque error when compiling to WASM or ASM.js if apt install has installed too old of a version of npm based on your operating system kernel. This can be manually overridden from npm's internal commands