This documentation is available as Markdown for AI agents and LLMs. See the full Markdown index or append .md to any documentation URL.

A reference of configuration options for custom builds with EAS Build.

Creating custom builds for EAS Build helps customize the build process for your project.

YAML syntax for custom builds

Custom build config files are stored inside the .eas/build directory path. They use YAML syntax and must have a .yml or .yaml file extension. If you are new to YAML or want to learn more about the syntax, see Learn YAML in Y minutes.

build

Defined to describe a custom build configuration. All config options to create a custom build are specified under it.

name

The name of your custom build that is used to identify it in the build logs. EAS Build uses this property to display the name of your build in the dashboard.

For example, the build name is Run tests:

build:
  name: Run tests
  steps:
    - eas/checkout
    - run:
        name: Install dependencies
        command: npm install

steps

Steps are used to describe a list of actions, either in the form of commands or function calls. These actions are executed when a custom build runs on EAS Build. You can define single or multiple steps in a build config. However, it is required to define at least one step per build.

Each step is configured with the following properties:

steps[].run

The run key is used to trigger a set of instructions. For example, a run key is used to install dependencies using the npm install command:

build:
  name: Install npm dependencies
  steps:
    - eas/checkout
    - run:
        name: Install dependencies
        command: npm install

You can also use steps[].run to execute single or multiline shell commands:

build:
  name: Run inline shell commands
  steps:
    - run: echo "Hello world"
    - run: |
        echo "Multiline"
        echo "bash commands"

Use a single step

For example, a build config with the following steps will print "Hello world":

build:
  name: Greeting
  steps:
    - run: echo "Hello world"

Note: - before run counts as indentation.

Use multiple steps

When multiple steps are defined, they are executed sequentially. For example, a build config with the following steps will first check out the project, install npm dependencies, and then run a command to run tests:

build:
  name: Run tests
  steps:
    - eas/checkout
    - run:
        name: Install dependencies
        command: npm install
    - run:
        name: Run tests
        command: |
          echo "Running tests..."
          npm test

Sharing environment variables with other steps

Environment variables exported (using export) in one step's command are not automatically exposed to other steps. To share an environment variable with other steps, use the set-env executable.

set-env expects to be called with two arguments: environment variable's name and value. For example, set-env NPM_TOKEN "abcdef" will expose $NPM_TOKEN variable with value abcdef to other steps.

Note: Variables shared with set-env are not automatically exported locally. You need to call export yourself.

build:
  name: Shared environment variable example
  steps:
    - run:
        name: Set environment variables
        command: |
          set -x

          # Set variable
          ENV_TEST_LOCAL="present-only-in-current-shell-context"
          # Set and export variable
          export ENV_TEST_LOCAL_EXPORT="present-in-current-step"
          # Set shared variable
          set-env ENV_TEST_SET_ENV "present-in-following-steps"

          # Will print "ENV_TEST_LOCAL: present-only-in-current-shell-context"
          # because current shell has access to this local variable.
          echo "ENV_TEST_LOCAL: $ENV_TEST_LOCAL"

          # Will print "ENV_TEST_LOCAL_EXPORT: present-in-current-step"
          # because export also sets the local variable value.
          echo "ENV_TEST_LOCAL_EXPORT: $ENV_TEST_LOCAL_EXPORT"

          # Will "ENV_TEST_SET_ENV: "
          # because set-env does not set or export variables.
          echo "ENV_TEST_SET_ENV: $ENV_TEST_SET_ENV"

          # Will only print LOCALLY_EXPORTED_ENV,
          # because it is the only export-ed variable.
          env | grep ENV_TEST_
    - run:
        name: Check variables values in next step
        command: |
          set -x

          # Will print "ENV_TEST_LOCAL: ", because ENV_TEST_LOCAL
          # is only a local variable in previous step.
          echo "ENV_TEST_LOCAL: $ENV_TEST_LOCAL"

          # Will print "ENV_TEST_LOCAL_EXPORT: "
          # because export does not share a variable to other steps.
          echo "ENV_TEST_LOCAL_EXPORT: $ENV_TEST_LOCAL_EXPORT"

          # Will print "ENV_TEST_SET_ENV: present-in-following-steps"
          # because set-env "exported" variable to other steps.
          echo "ENV_TEST_SET_ENV: $ENV_TEST_SET_ENV"

          # Will only print ENV_TEST_SET_ENV,
          # because set-env "exported" it to other steps.
          env | grep ENV_TEST_

steps[].run.name

The name used in build logs to display the name of the step.

steps[].run.command

The command defines a custom shell command to run when a step is executed. It is required to define a command for each step. It can be a multiline shell command:

build:
  name: Run tests
  steps:
    - eas/checkout
    - run:
        name: Run tests
        command: |
          echo "Running tests..."
          npm test

steps[].run.working_directory

The working_directory is used to define an existing directory from the project's root directory. After an existing path is defined in a step, using it changes the current directory for that step. For example, a step is created to list all the assets inside the assets directory, which is a directory in your Expo project. The working_directory is set to assets:

build:
  name: Demo
  steps:
    - eas/checkout
    - run:
        name: List assets
        working_directory: assets
        command: ls -la

steps[].run.shell

Used to define the default executable shell for a step. For example, the step's shell is set to /bin/sh:

build:
  name: Demo
  steps:
    - run:
        shell: /bin/sh
        command: |
          echo "Steps can use another shell"
          ps -p $$

steps[].run.inputs

Input values are provided to a step. For example, you can use input to provide a value:

build:
  name: Demo
  steps:
    - run:
        name: Say Hi
        inputs:
          name: Expo
        command: echo "Hi, ${ inputs.name }!"

steps[].run.outputs

An output value is expected during a step. For example, a step has an output value of Hello world:

build:
  name: Demo
  steps:
    - run:
        name: Produce output
        outputs: [value]
        command: |
          echo "Producing output for another step"
          set-output value "Output from another step..."

steps[].run.outputs.required

An output value can use a boolean to indicate if the output value is required or not. For example, a function does not have a required output value:

build:
  name: Demo
  steps:
    - run:
        name: Produce another output
        id: id456
        outputs:
          - required_param
          - name: optional_param
            required: false
        command: |
          echo "Producing more output"
          set-output required_param "abc 123 456"

steps[].run.id

Defining an id for a step allows:

• Calling the same function that produces one or more outputs multiple times
• Using the output from one step to another

Call the same function one or more times

For example, the following function generates a random number:

functions:
  random:
    name: Generate random number
    outputs: [value]
    command: set-output value `random_number`

In a build config, let's use the random function to generate two random numbers and print them:

build:
  name: Functions Demo
  steps:
    - random:
        id: random_1
    - random:
        id: random_2
    - run:
        name: Print random numbers
        inputs:
          random_1: ${ steps.random_1.value }
          random_2: ${ steps.random_2.value }
        command: |
          echo "${ inputs.random_1 }"
          echo "${ inputs.random_2 }"

Use output from one step to another

For example, the following build config demonstrates how to use output from one step to another:

build:
  name: Outputs demo
  steps:
    - run:
        name: Produce output
        id: id123 # <---- !!!
        outputs: [foo]
        command: |
          echo "Producing output for another step"
          set-output foo bar
    - run:
        name: Use output from another step
        inputs:
          foo: ${ steps.id123.foo }
        command: |
          echo "foo = \"${ inputs.foo }\""

functions

Defined to describe a reusable function that can be used in a build config. All config options to create a function are specified with the following properties:

functions.[function_name]

The [function_name] is the name of a function that you define to identify it in the build.steps. For example, you can define a function with the name greetings:

functions:
  greetings:
    name: Say Hi!

functions.[function_name].name

The name that is used in build logs to display the name of the function. For example, a function with the display name Say Hi!:

functions:
  greetings:
    name: Say Hi!

functions.[function_name].inputs

Input values are provided to a function.

inputs[].name

The name of the input value. It is used as an identifier to access the input value such as in bash command interpolation.

functions:
  greetings:
    name: Say Hi!
    inputs:
      - name: name
        default_value: Hello world
    command: echo "${ inputs.name }!"

inputs[].required

Boolean to indicate if the input value is required or not. For example, a function does not have a required value:

functions:
  greetings:
    name: Say Hi!
    inputs:
      - name: name
        required: false

inputs[].type

The type of the input value. It can be either string, num or json.

Input values set in the function call as well as default_value and allowed_values for the function are validated against the type.

The default input type is string.

For example, a function has an input value of type string:

functions:
  greetings:
    name: Say Hi!
    inputs:
      - name: name
        type: string
      - name: age
        type: num
      - name: other_data
        type: json

inputs[].default_value

You can use default_value to provide one default input. For example, a function has a default value of Hello world:

functions:
  greetings:
    name: Say Hi!
    inputs:
      - name: name
        default_value: Hello world

inputs[].allowed_values

You can use allowed_values to provide multiple values in an array. For example, a function has multiple allowed values:

functions:
  greetings:
    name: Say Hi!
    inputs:
      - name: name
        default_value: Hello world
        allowed_values: [Hi, Hello, Hey]
        type: string

Multiple input values

Multiple input values can be provided to a function.

functions:
  greetings:
    name: Say Hi!
    inputs:
      - name: name
        default_value: Expo
      - name: greeting
        default_value: Hi
        allowed_values: [Hi, Hello]
    command: echo "${ inputs.greeting }, ${ inputs.name }!"

functions.[function_name].outputs

An output value is expected from a function. For example, a function has an output value of Hello world:

functions:
  greetings:
    name: Say Hi!
    outputs: [value]
    command: set-output value "Hello world"

outputs[].name

The name of the output value. It is used as an identifier to access the output value in another step:

functions:
  greetings:
    name: Say Hi!
    outputs:
      - name: name

outputs[].required

Boolean to indicate if the output value is required or not. For example, a function does not have a required output value:

functions:
  greetings:
    name: Say Hi!
    outputs:
      - name: value
        required: false

functions.[function_name].command

Used to define the command to run when a function is executed, if you wish the function to be a simple shell script. Each function is required to define either a command or a path to JS/TS module implementing the function. For example, the command echo "Hello world" is used to print a message:

functions:
  greetings:
    name: Say Hi!
    command: echo "Hi!"

functions.[function_name].path

Used to define the path to a JavaScript/TypeScript module implementing the function. Each function is required to define either a command or a path property. For example, the path ./greetings is used to execute a greetings function declared in the greetings module:

functions:
  greetings:
    name: Say Hi!
    path: ./greetings

Learn more about building and using custom TypeScript/JavaScript functions.

functions.[function_name].shell

Used to define the default executable shell for a step where a function is executed. For example, the step's shell is set to /bin/sh:

functions:
  greetings:
    name: Say Hi!
    shell: /bin/sh
    command: echo "Hi!"

functions.[function_name].supported_platforms

Used to define the supported platforms for a function. Defaults to all platforms. Allowed platforms: darwin, linux.

For example, the function's supported platform is darwin (macOS):

functions:
  greetings:
    name: Say Hi!
    supported_platforms: [darwin]
    command: echo "Hi!"

import

A config file path list used to import functions from other config files. Imported files cannot have the build section.

For example, the following build config imports two files and calls two imported functions - say_hi and say_bye.

import:
  - common-functions.yml
  - another-file.yml

build:
  steps:
    - say_hi
    - say_bye

functions:
  say_hi:
    name: Say Hi!
    command: echo "Hi!"

functions:
  say_bye:
    name: Say bye :(
    command: echo "Bye!"

Functions

Built-in EAS functions

EAS provides a set of built-in reusable functions that you can use in a build config without defining the function definition.

Tip: Any function that is built-in and provided by EAS must start with the eas/ prefix.

eas/build

The all-in-one function that encapsulates the entire EAS Build build process. It resolves the best build configuration based on your build profile's settings from eas.json.

It's ideal for people who want to have the build done without worrying about altering and configuring the build process manually. It can be a great starting point for your custom build configuration if you are interested in using other custom steps before or after the build process and you don't want to change the build process itself.

build:
  name: Run a build using a single command
  steps:
    - eas/build

To have more control over the build process and customize it as per your requirements, see the following custom functions and steps that run in the background by eas/build. They are executed as a build process based on your build profile's configuration.

Android

When a build configuration is using withoutCredentials:

• eas/checkout
• eas/use_npm_token
• eas/install_node_modules
• eas/resolve_build_config
• eas/prebuild
• eas/configure_eas_update
• eas/run_gradle
• eas/find_and_upload_build_artifacts

When a build configuration uses credentials (for both internal and store distribution builds):

• eas/checkout
• eas/use_npm_token
• eas/install_node_modules
• eas/resolve_build_config
• eas/prebuild
• eas/configure_eas_update
• eas/inject_android_credentials
• eas/configure_android_version
• eas/run_gradle
• eas/find_and_upload_build_artifacts

iOS

When a build configuration is using withoutCredentials or simulator:

• eas/checkout
• eas/use_npm_token
• eas/install_node_modules
• eas/resolve_build_config
• eas/prebuild
• Install pods using the pod install command
• eas/configure_eas_update
• eas/generate_gymfile_from_template
• eas/run_fastlane
• eas/find_and_upload_build_artifacts

When a build configuration uses credentials (for both internal and store distribution builds):

• eas/checkout
• eas/use_npm_token
• eas/install_node_modules
• eas/resolve_build_config
• eas/resolve_apple_team_id_from_credentials
• eas/prebuild
• Install pods using the pod install command
• eas/configure_eas_update
• eas/configure_ios_credentials
• eas/configure_ios_version
• eas/generate_gymfile_from_template
• eas/run_fastlane
• eas/find_and_upload_build_artifacts

You can replace the eas/build command call by using these steps in your YAML configuration file:

Known limitations

• It doesn't accept any inputs, and the resolved build process will be configured based on your build profile from eas.json.
• The build process produced by eas/build is not configurable and you can't customize it. If you need to customize the build process, use the subset of functions and steps that are executed behind the scenes by this function and configure them manually in the YAML configuration file, as shown in the examples above.

eas/maestro_test

All-in-one function that installs Maestro, prepares a testing environment (Android Emulator or iOS Simulator), and tests the app.

Your project must be configured to use the old Build Infrastructure to start Android Emulator. Go to Project settings to configure. See this changelog post for more information.

build:
  name: Build and test
  steps:
    - eas/build
    - eas/maestro_test:
        inputs:
          flow_path: |
            maestro/sign_in.yml
            maestro/create_post.yml
            maestro/sign_out.yml

build:
  name: Build and test iOS simulator app
  steps:
    - eas/checkout
    - eas/maestro_test:
        app_path: ./fixtures/my_app.app
        inputs:
          flow_path: |
            maestro/sign_in.yml
            maestro/create_post.yml
            maestro/sign_out.yml

build:
  name: Build and test Android emulator app
  steps:
    - eas/checkout
    - eas/maestro_test:
        app_path: ./fixtures/my_app.apk
        inputs:
          flow_path: |
            maestro/sign_in.yml
            maestro/create_post.yml
            maestro/sign_out.yml

Behind the scenes, it uses:

• eas/install_maestro to install Maestro
• eas/start_android_emulator to start an Android Emulator if needed
• eas/start_ios_simulator to start an iOS Simulator if needed
• Custom run to install .apk to the running Android Emulator and .app to iOS Simulator
• Series of run to execute maestro test for each of the provided flows
• eas/upload_artifact to upload Maestro test artifacts as build artifact

We have observed that Maestro tests often time out if run on images with Xcode 15.0 or 15.2. Use the latest image to avoid any issues.

If you need to customize the Maestro version, run a specific Android Emulator or iOS Simulator, or upload multiple build artifacts you will need to write this series of steps yourself.

build:
  name: Build and test (Android, expanded)
  steps:
    - eas/build
    - eas/install_maestro
    - eas/start_android_emulator:
        inputs:
          system_package_name: system-images;android-34;default;x86_64
    - run:
        command: |
          # shopt -s globstar is necessary to add /**/ support
          shopt -s globstar
          # shopt -s nullglob is necessary not to try to install
          # SEARCH_PATH literally if there are no matching files.
          shopt -s nullglob

          SEARCH_PATH="android/app/build/outputs/**/*.apk"
          FILES_FOUND=false

          for APP_PATH in $SEARCH_PATH; do
            FILES_FOUND=true
            echo "Installing \\"$APP_PATH\\""
            adb install "$APP_PATH"
          done

          if ! $FILES_FOUND; then
            echo "No files found matching \\"$SEARCH_PATH\\". Are you sure you've built an Emulator app?"
            exit 1
          fi
    - run:
        command: |
          maestro test maestro/flow.yml
    - eas/upload_artifact:
        name: Upload test artifact
        if: ${ always() }
        inputs:
          type: build-artifact
          path: ${ eas.env.HOME }/.maestro/tests

build:
name: Build and test (iOS, expanded)
steps:
  - eas/build
  - eas/install_maestro
  - eas/start_ios_simulator
  - run:
      command: |
        # shopt -s nullglob is necessary not to try to install
        # SEARCH_PATH literally if there are no matching files.
        shopt -s nullglob

        SEARCH_PATH="ios/build/Build/Products/*simulator/*.app"
        FILES_FOUND=false

        for APP_PATH in $SEARCH_PATH; do
          FILES_FOUND=true
          echo "Installing \\"$APP_PATH\\""
          xcrun simctl install booted "$APP_PATH"
        done

        if ! $FILES_FOUND; then
          echo "No files found matching \\"$SEARCH_PATH\\". Are you sure you've built a Simulator app?"
          exit 1
        fi
  - run:
      command: |
        maestro test maestro/flow.yml
  - eas/upload_artifact:
      name: Upload test artifact
      if: ${ always() }
      inputs:
        type: build-artifact
        path: ${ eas.env.HOME }/.maestro/tests

eas/checkout

Checks out your project source files.

build:
  name: List files
  steps:
    - eas/checkout
    - run:
        name: List assets
        run: ls assets

For builds with Git-based project sources, the step uses the build's recorded commit by default. Use ref to check out a different branch, tag, or commit:

build:
  name: Check out a specific ref
  steps:
    - eas/checkout:
        inputs:
          ref: feature/add-icon
    - eas/build

ref accepts:

• A branch, as a bare name such as feature/add-icon or a qualified ref such as refs/heads/feature/add-icon. The repository ends up on that branch.
• A tag, as a qualified ref such as refs/tags/v1.2.3. The repository ends up on a detached HEAD.
• A full commit SHA. The repository ends up on a detached HEAD.

The ref input only works when your project sources come from a Git repository, for example, a build triggered through the GitHub integration. Local builds and uploaded project tarballs do not support it. Place the step before eas/build, which checks out the project internally.

eas/use_npm_token

Configures Node package managers (bun, npm, pnpm, or Yarn) for use with private packages, published either to npm or a private registry.

Set NPM_TOKEN in your project's secrets, and this function will configure the build environment by creating .npmrc with the token.

build:
  name: Install private npm modules
  steps:
    - eas/checkout
    - eas/use_npm_token
    - run:
        name: Install dependencies
        run: npm install # <---- Can now install private packages

eas/install_node_modules

Installs node_modules using the package manager (bun, npm, pnpm, or Yarn) detected based on your project. Works with monorepos.

build:
  name: Install node modules
  steps:
    - eas/checkout
    - eas/install_node_modules

eas/restore_build_cache

Restores a previously saved build cache from a specified key. This is useful for speeding up builds by reusing cached artifacts like compiled dependencies, build tools, or other intermediate build outputs.

build:
  name: Build with cache
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/restore_build_cache:
        inputs:
          key: cache-${{ hashFiles('package-lock.json') }}
          restore_keys: cache
          path: /path/to/cache

build:
  name: Build with cache
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/restore_build_cache:
        inputs:
          key: cache-${{ hashFiles('package-lock.json') }}
          path: /path/to/cache

eas/save_build_cache

Saves a build cache to a specified key. This allows you to persist build artifacts, compiled dependencies, or other intermediate outputs that can be reused in subsequent builds to speed up the build process.

build:
  name: Build with cache
  steps:
    - eas/checkout
    - eas/restore_build_cache:
        inputs:
          key: cache-${{ hashFiles('package-lock.json') }}
          path: /path/to/cache
    - eas/install_node_modules
    - eas/prebuild
    - eas/run_gradle
    - eas/save_build_cache:
        inputs:
          key: cache-${{ hashFiles('package-lock.json') }}
          path: /path/to/cache

eas/resolve_build_config

Resolves and prints the build configuration. If the build has been triggered by the GitHub integration, it will update the current job and metadata context values. It should be called after installing the dependencies because the config may be influenced by config plugins.

This function is automatically executed by the eas/build function group.

eas/get_credentials_for_build_triggered_by_github_integration

Deprecated: Replace this step with eas/resolve_build_config.

eas/resolve_apple_team_id_from_credentials

This function is only available for iOS builds.

Resolves the Apple team ID value based on build credentials provided in the inputs.credentials. The resolved Apple team ID is stored in the outputs.apple_team_id output value.

build:
  name: Run prebuild script
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }

eas/prebuild

Runs the expo prebuild command using the package manager (bun, npm, pnpm, or Yarn) detected based on your project with the command best suited for your build type and build environment.

build:
  name: Run prebuild script
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }

build:
  name: Run prebuild script
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild

eas/configure_eas_update

To use this function you need to have EAS Update configured for your project.

Configures runtime version and release channel for your build.

build:
  name: Configure EAS Update
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update

build:
  name: Configure EAS Update
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update:
        inputs:
          runtime_version: 1.0.0
          channel: mychannel

eas/inject_android_credentials

This function is only available for Android builds.

Configures Android keystore with credentials on the builder and injects app signing config using these credentials into gradle config.

build:
  name: Android credentials
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/inject_android_credentials

eas/configure_ios_credentials

This function is only available for iOS builds.

Configures iOS credentials on the builder. Modifies the configuration of the Xcode project by assigning provisioning profiles to the targets.

build:
  name: iOS credentials
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }
    - eas/configure_ios_credentials

eas/configure_android_version

This function is only available for Android builds.

Configures the version of your Android app. It's used to set a version when using remote app version management.

It's not mandatory to use this function, if it's not used the version from native code generated during the prebuild phase will be used.

build:
  name: Configure Android version
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update
    - eas/inject_android_credentials
    - eas/configure_android_version

build:
  name: Configure Android version
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update
    - eas/inject_android_credentials
    - eas/configure_android_version:
        inputs:
          version_code: '123'
          version_name: '1.0.0'

eas/configure_ios_version

This function is only available for iOS builds.

Configures the version of your iOS app. It's used to set a version when using remote app version management.

It's not mandatory to use this function, if it's not used the version from native code generated during the prebuild phase will be used.

build:
  name: Configure iOS version
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }
    - eas/configure_eas_update
    - eas/configure_ios_credentials
    - eas/configure_ios_version

build:
  name: Configure iOS version
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }
    - eas/configure_eas_update
    - eas/configure_ios_credentials
    - eas/configure_ios_version:
        inputs:
          build_number: '123'
          app_version: '1.0.0'

eas/run_gradle

This function is only available for Android builds.

Runs a Gradle command to build an Android app.

build:
  name: Build Android app
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update
    - eas/inject_android_credentials
    - eas/run_gradle

build:
  name: Build Android app
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update
    - eas/inject_android_credentials
    - eas/run_gradle:
        inputs:
          command: :app:bundleRelease

eas/generate_gymfile_from_template

This function is only available for iOS builds.

Generates a Gymfile used to build the iOS app using Fastlane from a template.

Default template used when credentials are passed:

suppress_xcode_output(true)
clean(<%- CLEAN %>)

scheme("<%- SCHEME %>")
<% if (BUILD_CONFIGURATION) { %>
configuration("<%- BUILD_CONFIGURATION %>")
<% } %>

export_options({
method: "<%- EXPORT_METHOD %>",
provisioningProfiles: {<% _.forEach(PROFILES, function(profile) { %>
    "<%- profile.BUNDLE_ID %>" => "<%- profile.UUID %>",<% }); %>
}<% if (ICLOUD_CONTAINER_ENVIRONMENT) { %>,
iCloudContainerEnvironment: "<%- ICLOUD_CONTAINER_ENVIRONMENT %>"
<% } %>
})

export_xcargs "OTHER_CODE_SIGN_FLAGS=\\"--keychain <%- KEYCHAIN_PATH %>\\""

disable_xcpretty(true)
buildlog_path("<%- LOGS_DIRECTORY %>")

output_directory("<%- OUTPUT_DIRECTORY %>")

Default template used when credentials are not passed (simulator build):

suppress_xcode_output(true)
clean(<%- CLEAN %>)

scheme("<%- SCHEME %>")
<% if (BUILD_CONFIGURATION) { %>
configuration("<%- BUILD_CONFIGURATION %>")
<% } %>

derived_data_path("<%- DERIVED_DATA_PATH %>")
skip_package_ipa(true)
skip_archive(true)
destination("<%- SCHEME_SIMULATOR_DESTINATION %>")

disable_xcpretty(true)
buildlog_path("<%- LOGS_DIRECTORY %>")

CLEAN, SCHEME, BUILD_CONFIGURATION, EXPORT_METHOD, PROFILES, ICLOUD_CONTAINER_ENVIRONMENT, KEYCHAIN_PATH, LOGS_DIRECTORY, OUTPUT_DIRECTORY, DERIVED_DATA_PATHand SCHEME_SIMULATOR_DESTINATION values are provided to the template based on the inputs and default internal configuration of EAS Build.

build:
  name: Generate Gymfile template
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }
    - eas/configure_eas_update
    - eas/configure_ios_credentials
    - eas/generate_gymfile_from_template:
        inputs:
          credentials: ${ eas.job.secrets.buildCredentials }

build:
  name: Generate Gymfile template
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/generate_gymfile_from_template

However, you can also use other custom properties in the template, by specifying your custom template in inputs.template and providing the values for the custom properties in the inputs.extra object.

build:
  name: Generate Gymfile template
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }
    - eas/configure_eas_update
    - eas/configure_ios_credentials
    - eas/generate_gymfile_from_template:
        inputs:
          credentials: ${ eas.job.secrets.buildCredentials }
          extra:
            MY_VALUE: my value
          template: |
            suppress_xcode_output(true)
            clean(<%- CLEAN %>)

            scheme("<%- SCHEME %>")
            <% if (BUILD_CONFIGURATION) { %>
            configuration("<%- BUILD_CONFIGURATION %>")
            <% } %>

            export_options({
            method: "<%- EXPORT_METHOD %>",
            provisioningProfiles: {<% _.forEach(PROFILES, function(profile) { %>
                "<%- profile.BUNDLE_ID %>" => "<%- profile.UUID %>",<% }); %>
            }<% if (ICLOUD_CONTAINER_ENVIRONMENT) { %>,
            iCloudContainerEnvironment: "<%- ICLOUD_CONTAINER_ENVIRONMENT %>"
            <% } %>
            })

            export_xcargs "OTHER_CODE_SIGN_FLAGS=\"--keychain <%- KEYCHAIN_PATH %>\""

            disable_xcpretty(true)
            buildlog_path("<%- LOGS_DIRECTORY %>")

            output_directory("<%- OUTPUT_DIRECTORY %>")

            sth_else("<%- MY_VALUE %>")

eas/run_fastlane

This function is only available for iOS builds.

Runs fastlane gym command against the Gymfile located in the ios project directory to build the iOS app.

build:
  name: Build iOS app
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }
    - eas/configure_eas_update
    - eas/configure_ios_credentials
    - eas/generate_gymfile_from_template:
        inputs:
          credentials: ${ eas.job.secrets.buildCredentials }
    - eas/run_fastlane

build:
  name: Build iOS app
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update
    - eas/generate_gymfile_from_template
    - eas/run_fastlane

eas/find_and_upload_build_artifacts

You can currently upload each artifact type only once per build job.
If you use eas/find_and_upload_build_artifacts while having buildArtifactPaths configured in your build profile and the step finds and uploads some build artifacts, any following eas/upload_artifact step will fail.
To solve this, for now, we recommend removing buildArtifactPaths from custom build's profiles and uploading artifacts manually with eas/upload_artifact in the YAML if you need to call it there.

Automatically finds and uploads application archive, additional build artifacts, and Xcode logs from the default locations and using the buildArtifactPaths configuration. Uploads found artifacts to the EAS servers.

build:
  name: Build iOS app
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials
    - eas/prebuild:
        inputs:
          clean: false
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }
    - eas/configure_eas_update
    - eas/configure_ios_credentials
    - eas/generate_gymfile_from_template:
        inputs:
          credentials: ${ eas.job.secrets.buildCredentials }
    - eas/run_fastlane
    - eas/find_and_upload_build_artifacts

build:
  name: Build iOS app
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update
    - eas/generate_gymfile_from_template
    - eas/run_fastlane
    - eas/find_and_upload_build_artifacts

build:
  name: Build Android app
  steps:
    - eas/checkout
    - eas/install_node_modules
    - eas/prebuild
    - eas/configure_eas_update
    - eas/inject_android_credentials
    - eas/run_gradle
    - eas/find_and_upload_build_artifacts

eas/upload_artifact

Uploads files from the job's workspace as an artifact attached to the run. Uploaded artifacts appear in the run's Artifacts section and can be retrieved in a later job with eas/download_artifact.

You can currently upload each artifact type only once per build job.
If you use eas/find_and_upload_build_artifacts while having buildArtifactPaths configured in your build profile and the step finds and uploads some build artifacts, any following eas/upload_artifact step will fail.
To solve this, for now, we recommend removing buildArtifactPaths from custom build's profiles and uploading artifacts manually with eas/upload_artifact in the YAML if you need to call it there.

build:
  name: Upload artifacts
  steps:
    - eas/checkout
    # - ...
    - eas/upload_artifact:
        name: Upload application archive
        inputs:
          path: fixtures/app-debug.apk
    - eas/upload_artifact:
        name: Upload artifacts
        inputs:
          type: build-artifact
          path: |
            assets/*.jpg
            assets/*.png

Outputs

eas/install_maestro

Makes sure Maestro, the mobile UI testing framework, is installed along with all its dependencies.

build:
  name: Build and test
  steps:
    - eas/build
    # ... simulator/emulator setup
    - eas/install_maestro:
        inputs:
          maestro_version: 1.35.0
    - run:
        command: maestro test flows/signin.yml
    - eas/upload_artifact:
        name: Upload Maestro artifacts
        inputs:
          type: build-artifact
          path: ${ eas.env.HOME }/.maestro/tests

eas/start_android_emulator

Starts an Android Emulator you can use to test your apps on. Only available when running a build for Android.

Your project must be configured to use the old Build Infrastructure to start Android Emulator. Go to Project settings to configure. See this changelog post for more information.

build:
  name: Build and test
  steps:
    - eas/build
    - eas/start_android_emulator:
        inputs:
          system_image_package: system-images;android-30;default;x86_64
    # ... Maestro setup and tests

eas/start_ios_simulator

Starts an iOS Simulator you can use to test your apps on. Only available when running a build for iOS.

build:
  name: Build and test
  steps:
    - eas/build
    - eas/start_ios_simulator
    # ... Maestro setup and tests

eas/send_slack_message

Sends a specified message to a configured Slack webhook URL, which then posts it in the related Slack channel. The message can be specified as plaintext or as a Slack Block Kit message.

You can reference build job properties and use other steps outputs in the message for dynamic evaluation. For example, 'Build URL: ${ eas.job.expoBuildUrl }', Build finished with status: ${ steps.run_fastlane.status_text }, Build failed with error: ${ steps.run_gradle.error_text }.

build:
  name: Slack your team from custom build
  steps:
    - eas/send_slack_message:
        name: Send Slack message to a given webhook URL
        inputs:
          message: 'This is a message to plain input URL'
          slack_hook_url: 'https://hooks.slack.com/services/[rest_of_hook_url]'
    - eas/send_slack_message:
        name: Send Slack message to a default webhook URL from SLACK_HOOK_URL secret
        inputs:
          message: 'This is a test message to default URL from SLACK_HOOK_URL secret'
    - eas/send_slack_message:
        name: Send Slack message to a webhook URL from specified secret
        inputs:
          message: 'This is a test message to a URL from specified secret'
          slack_hook_url: ${ eas.env.ANOTHER_SLACK_HOOK_URL }

    - eas/build
    - eas/send_slack_message:
        if: ${ always() }
        name: Send Slack message when the build finishes (Android)
        inputs:
          message: |
            This is a test message when Android build finishes
            Status: `${ steps.run_gradle.status_text }`
            Link: `${ eas.job.expoBuildUrl }`
    - eas/send_slack_message:
        if: ${ always() }
        name: Send Slack message when the build finishes (iOS)
        inputs:
          message: |
            This is a test message when iOS build finishes
            Status: `${ steps.run_fastlane.status_text }`
            Link: `${ eas.job.expoBuildUrl }`
    - eas/send_slack_message:
        if: ${ failure() }
        name: Send Slack message when the build fails (Android)
        inputs:
          message: |
            This is a test message when Android build fails
            Error: `${ steps.run_gradle.error_text }`
    - eas/send_slack_message:
        if: ${ failure() }
        name: Send Slack message when the build fails (iOS)
        inputs:
          message: |
            This is a test message when iOS build fails
            Error: `${ steps.run_fastlane.error_text }`
    - eas/send_slack_message:
        if: ${ success() }
        name: Send Slack message when the build succeeds
        inputs:
          message: |
            This is a test message when build succeeds
    - eas/send_slack_message:
        if: ${ always() }
        name: Send Slack message with Slack Block Kit layout
        inputs:
          payload:
            blocks:
              - type: section
                text:
                  type: mrkdwn
                  text: |-
                    Hello, Sir Developer

                     *Your build has finished!*
              - type: divider
              - type: section
                text:
                  type: mrkdwn
                  text: |-
                    *${ eas.env.EAS_BUILD_ID }*
                    *Status:* `${ steps.run_gradle.status_text }`
                    *Link:* `${ eas.job.expoBuildUrl }`
                accessory:
                  type: image
                  image_url: [your_image_url]
                  alt_text: alt text for image
              - type: divider
              - type: actions
                elements:
                  - type: button
                    text:
                      type: plain_text
                      text: 'Do a thing :rocket:'
                      emoji: true
                    value: a_thing
                  - type: button
                    text:
                      type: plain_text
                      text: 'Do another thing :x:'
                      emoji: true
                    value: another_thing

The following functions connect your build to PostHog. Run eas integrations:posthog:connect to link a PostHog project and set the environment variables these functions read. eas/posthog_capture_event uses your public project API key, while the other functions use a PostHog personal API key with the scopes noted for each one. For setup, see Using PostHog, and for complete workflows, see PostHog recipes for EAS Workflows.

eas/posthog_capture_event

Sends an analytics event to PostHog. Use it to mark builds, releases, and other milestones on your PostHog timeline.

When you do not provide a distinct_id, the event is sent anonymously and does not create a PostHog person profile.

build:
  name: Build and mark the release in PostHog
  steps:
    - eas/build
    - eas/posthog_capture_event:
        name: Capture a PostHog event
        inputs:
          event: store_build_finished
          properties:
            platform: ios
            profile: production

eas/posthog_flag_rollout

Enables, disables, or rolls out a PostHog feature flag. The function looks up the flag by key and then updates it. Provide at least one of active, rollout_percentage, or payload.

build:
  name: Roll out a PostHog feature flag
  steps:
    - eas/posthog_flag_rollout:
        name: Roll out the flag to 25 percent
        inputs:
          flag: new-checkout
          rollout_percentage: 25

eas/posthog_wait_for_metric

Pauses until a HogQL query returns a number that satisfies a comparison. Use it to gate on a metric, such as holding until the error count over the last few minutes stays low. The function runs the query every interval_seconds until the comparison is true or timeout_seconds elapses.

This step has no ignore_error input. A timeout or an unreadable query always fails the step.

build:
  name: Gate on the error count
  steps:
    - eas/posthog_wait_for_metric:
        name: Wait for the error count to stay low
        inputs:
          query: SELECT count() FROM events WHERE event = '$exception' AND timestamp > now() - INTERVAL 15 MINUTE
          operator: lt
          threshold: 10

Outputs

eas/posthog_wait_for_query

Pauses until a HogQL query returns true. Use it when the condition is easier to express in the query itself. For a numeric comparison with an explicit threshold, use eas/posthog_wait_for_metric instead. The step clears when the first column of the first row is true or a nonzero number.

Like eas/posthog_wait_for_metric, this step has no ignore_error input. A timeout or an unreadable query always fails the step.

build:
  name: Wait for a smoke test event
  steps:
    - eas/posthog_wait_for_query:
        name: Wait for the smoke test to pass
        inputs:
          query: SELECT count() > 0 FROM events WHERE event = 'smoke_test_passed' AND timestamp > now() - INTERVAL 30 MINUTE

eas/posthog_annotation

Creates a PostHog annotation on the project timeline. Annotations show up on your PostHog charts, which makes them useful for marking builds, releases, and other milestones next to the metrics they affect.

build:
  name: Annotate the release in PostHog
  steps:
    - eas/posthog_annotation:
        name: Create a PostHog annotation
        inputs:
          content: Published a production build

eas/posthog_upload_sourcemaps

Uploads JavaScript source maps to PostHog so that PostHog symbolicates stack traces in error tracking. Run it after the step that produces your bundle, in the same job, so the bundle and source maps are available on disk. Export with npx expo export --source-maps, and configure the PostHog Metro config from the Source maps guide so bundles carry the chunk IDs that match them to their source maps.

This step runs the PostHog CLI, which cannot tell a permissions error apart from any other failure. Unlike the other PostHog functions, setting ignore_error: true also hides authentication and scope errors.

build:
  name: Export and upload source maps
  steps:
    - eas/checkout
    - eas/install_node_modules
    - run:
        name: Export the bundle and source maps
        command: npx expo export --source-maps --platform ios
    - eas/posthog_upload_sourcemaps:
        name: Upload source maps to PostHog
        inputs:
          directory: dist

Using built-in EAS functions to build an app

Using the built-in EAS functions you can recreate the default EAS Build process for different build types.

For example, to trigger a build that creates internal distribution build for Android and a simulator build for iOS you can use the following configuration:

{
  %%placeholder-start%%... %%placeholder-end%%
  "build": {
    %%placeholder-start%%... %%placeholder-end%%
    "developmentBuild": {
      "distribution": "internal",
      "android": {
        "config": "development-build-android.yml"
      },
      "ios": {
        "simulator": true,
        "config": "development-build-ios.yml"
      }
    }
    %%placeholder-start%%... %%placeholder-end%%
  }
  %%placeholder-start%%... %%placeholder-end%%
}

build:
  name: Simple internal distribution Android build
  steps:
    - eas/checkout

    - eas/install_node_modules

    - eas/prebuild

    - eas/inject_android_credentials

    - eas/run_gradle

    - eas/find_and_upload_build_artifacts

build:
  name: Simple simulator iOS build
  steps:
    - eas/checkout

    - eas/install_node_modules

    - eas/prebuild

    - run:
        name: Install pods
        working_directory: ./ios
        command: pod install

    - eas/generate_gymfile_from_template

    - eas/run_fastlane

    - eas/find_and_upload_build_artifacts

To create a Google Play Store build for Android and an Apple App Store build for iOS you can use the following configuration:

{
  %%placeholder-start%%... %%placeholder-end%%
  "build": {
    %%placeholder-start%%... %%placeholder-end%%
    "productionBuild": {
      "android": {
        "config": "production-build-android.yml"
      },
      "ios": {
        "config": "production-build-ios.yml"
      }
    }
    %%placeholder-start%%... %%placeholder-end%%
  }
  %%placeholder-start%%... %%placeholder-end%%
}

build:
  name: Customized Android Play Store build example
  steps:
    - eas/checkout

    - eas/install_node_modules

    - eas/prebuild

    - eas/inject_android_credentials

    - eas/run_gradle

    - eas/find_and_upload_build_artifacts

build:
  name: Customized iOS App Store build example
  steps:
    - eas/checkout

    - eas/install_node_modules

    - eas/resolve_apple_team_id_from_credentials:
        id: resolve_apple_team_id_from_credentials

    - eas/prebuild:
        inputs:
          apple_team_id: ${ steps.resolve_apple_team_id_from_credentials.apple_team_id }

    - run:
        name: Install pods
        working_directory: ./ios
        command: pod install

    - eas/configure_ios_credentials

    - eas/generate_gymfile_from_template:
        inputs:
          credentials: ${ eas.job.secrets.buildCredentials }

    - eas/run_fastlane

    - eas/find_and_upload_build_artifacts

Check out the example repository for more detailed examples:

Use a reusable function in a build

For example, a custom build config with the following reusable function contains a single command to print a message that is echoed.

functions:
  greetings:
    - name: name
      default_value: Hello world
    inputs: [value]
    command: echo "${ inputs.name }, { inputs.value }"

The above function can be used in a build as follows:

build:
  name: Functions Demo
  steps:
    - greetings:
        inputs:
          value: Expo

Tip: build.steps can execute multiple reusable functions sequentially.

Override values in a build

You can override values for the following properties:

• working_directory
• name
• shell

For example, a reusable function called list_files:

functions:
  list_files:
    name: List files
    command: ls -la

When list_files is called in a build config, it lists all files in the root directory of a project:

build:
  name: List files
  steps:
    - eas/checkout
    - list_files

You can use the working_directory property to override the behavior in the function call to list the files in a different directory by specifying the path to that directory:

build:
  name: List files
    steps:
      - eas/checkout
      - list_files:
          working_directory: /a/b/c