LicenseChecker is a command line tool checking licenses of swift package libraries that your app depends on. It can detect libraries that are not included in a whitelist specifying the license type or library name.

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Execution Example

$ license-checker --source-packages-path ~/SourcePackages --white-list-path ~/white-list.json 
abseil               Apache
BoringSSL-GRPC       BoringSSL
Eureka               MIT
Firebase             Apache
GoogleAppMeasurement Apache
GoogleDataTransport  Apache
GoogleUtilities      MIT
gRPC                 Apache
GTMSessionFetcher    Apache
Kanna                MIT
KeychainAccess       MIT
Kingfisher           MIT
leveldb              BSD
LicenseChecker       unknown
LicenseList          MIT
nanopb               zlib
ObjectMapper         MIT
Promises             Apache
R.swift.Library      MIT
Reachability         MIT
RxGesture            MIT
RxSwift              MIT
SwiftProtobuf        Apache
✅ No problems with library licensing.


  • Written in Swift 5
  • Compatible with macOS 12.0+
  • Development with Xcode 14.0+

How to Use

  1. Prepare a white list (white-list.json).
  • Specify the type of license to approve.
  • Specify the name of library to approve (for private libraries).

LicenseChecker supports the following licenses:

license type white list key
Apache license 2.0 Apache
MIT License MIT
BSD 3-clause Clear license BSD
zLib License zlib
BoringSSL BoringSSL

Sample of white-list.json

  "licenses": [
  "libraries": [

CommandPlugin & Run Script in BuildPhases (for Xcode Project)

  1. Add binary target & plugin to Package.swift.

    targets: [
            name: "license-checker",
            url: "",
            checksum: "7574f78ed51838fc690bf87ec317cb5acbff5bfb533bbd308c6865a2a6455eab"
            name: "LicenseCheckerCommand",
            capability: .command(
                intent: .custom(verb: "license-checker", description: "Run LicenseChecker"),
                permissions: []
            dependencies: ["license-checker"]
  2. Code Plugins/LicenseCheckerCommand/main.swift.

    import Foundation
    import PackagePlugin
    struct LicenseCheckerCommand: CommandPlugin {
        func performCommand(context: PluginContext, arguments: [String]) async throws {
            let licenseCheckerPath = try context.tool(named: "license-checker").path.string
            let rswiftURL = URL(fileURLWithPath: licenseCheckerPath, isDirectory: false)
            let process = try, arguments: arguments)
            if process.terminationReason != .exit || process.terminationStatus != 0 {
                Diagnostics.error("license-checker errors detected.")
  3. Add a Run Script in BuildPhases

    SOURCE_PACKAGES_PATH=`echo ${BUILD_DIR%Build/*}SourcePackages`
    xcrun --sdk macosx swift package --package-path ./RoadWarriorPackages \
    --allow-writing-to-directory ${SRCROOT} \
    license-checker -s ${SOURCE_PACKAGES_PATH} -w [Path to white-list.json]

    ⚠️ white-list.json must be included in Target Membership.

BuildToolPlugin (for Swift Package Project)

  1. Add binary target & plugin to Package.swift.

    targets: [
            name: "license-checker",
            url: "",
            checksum: "7574f78ed51838fc690bf87ec317cb5acbff5bfb533bbd308c6865a2a6455eab"
            name: "LicenseCheckerPlugin",
            capability: .buildTool(),
            dependencies: [
                .target(name: "license-checker")
  2. Code Plugins/LicenseCheckerPlugin/main.swift.

    import Foundation
    import PackagePlugin
    struct LicenseCheckerPlugin: BuildToolPlugin {
        func createBuildCommands(context: PluginContext, target: Target) async throws -> [Command] {
            let whiteListPath = "Path to white-list.json" // Please change accordingly.
            let pluginWorkDirectory = context.pluginWorkDirectory.string
            let regex = try NSRegularExpression(pattern: ".*SourcePackages")
            let range = NSMakeRange(0, pluginWorkDirectory.utf16.count)
            guard let result = regex.firstMatch(in: pluginWorkDirectory, range: range) else {
                throw NSError(domain: "com.cybozu.LicenseCheckerPlugin",
                              code: 1,
                              userInfo: ["message": "Failed to match"])
            let sourcePackageDirectory = NSString(string: pluginWorkDirectory)
                .substring(with: result.range(at: 0))
            return [
                    displayName: "LicenseChecker",
                    executable: try context.tool(named: "license-checker").path,
                    arguments: [
                    outputFilesDirectory: context.pluginWorkDirectory
  3. Use plugin in the target (Package.swift).

    targets: [
            name: "SomeFeature",
            resources: [.process("white-list.json")], // Please change accordingly.
            plugins: [
                .plugin(name: "LicenseCheckerPlugin")

license-checker (command help)

$ swift run license-checker -h
Building for debugging...
Build complete! (0.10s)
OVERVIEW: A tool to check license of swift package libraries.

USAGE: license-checker --source-packages-path <source-packages-path> --white-list-path <white-list-path>

  -s, --source-packages-path <source-packages-path>
                          Path of SourcePackages directory
  -w, --white-list-path <white-list-path>
                          Path of white-list.json
  --version               Show the version.
  -h, --help              Show help information.


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