Find Module

Before Placing Code

Search for related modules first:

• •Search for modules in the same domain area
• •Look at how similar features are organized
• •Check settings.gradle.kts for the full module tree

When uncertain about placement, search for similar components and follow existing patterns.

Code Placement by Type

Kotlin Multiplatform code (most features):

• •Location: app/ directory (domain/, libs/, ui/ subdirectories)
• •Source sets: commonMain for shared, androidMain/iosMain for platform-specific
• •See module index in docs for domain-specific placement

iOS-specific code (Swift/ObjC):

• •Location: app/ios/ directory
• •Only for Swift extensions, bridging code, or iOS-only features
• •Most iOS code should be in KMP modules under app/

Rust code (FFI bindings):

• •Location: app/rust/ directory
• •core-ffi: Core crypto operations
• •bdk-ffi: Bitcoin Development Kit bindings
• •firmware-ffi: Hardware wallet commands (NFC, firmware interactions)
• •Uses UniFFI for Kotlin/Swift bindings

Android-specific code:

• •Location: app/android/ directory
• •Only for Android platform code (Activities, Android-only features)
• •Most Android code should be in KMP modules under app/

Steps

1. •Check module index for existing modules in the domain
2. •Determine module type (:public, :impl, :fake)
3. •Place code in appropriate source set (prefer commonMain)

References

@docs/docs/mobile/architecture/gradle-modules.md @docs/docs/mobile/architecture/kmp.md