diff --git a/Sources/ProjectSpec/ProjectSpec.swift b/Sources/ProjectSpec/ProjectSpec.swift
new file mode 100644
index 00000000..b0566fec
--- /dev/null
+++ b/Sources/ProjectSpec/ProjectSpec.swift
@@ -0,0 +1,90 @@
+import Foundation
+import typealias JSONUtilities.JSONDictionary
+import PathKit
+
+extension Project {
+
+    public struct Spec {
+        public let relativePath: Path
+        public let jsonDictionary: JSONDictionary
+        public let subSpecs: [Spec]
+
+        public init(relativePath: Path, jsonDictionary: JSONDictionary, subSpecs: [Spec] = []) {
+            self.relativePath = relativePath
+            self.jsonDictionary = jsonDictionary
+            self.subSpecs = subSpecs
+        }
+
+        public init(filename: String, basePath: Path, relativePath: Path = "") throws {
+            let path = basePath + relativePath + filename
+
+            // Depending on the extension we will either load the file as YAML or JSON
+            var json: [String: Any]
+            if path.extension?.lowercased() == "json" {
+                let data: Data = try path.read()
+                let jsonData = try JSONSerialization.jsonObject(with: data, options: .allowFragments)
+                guard let jsonDictionary = jsonData as? [String: Any] else {
+                    fatalError("Invalid JSON at path \(path)")
+                }
+                json = jsonDictionary
+            } else {
+                json = try loadYamlDictionary(path: path)
+            }
+
+            var includeStrings: [String]
+            if let includeString = json["include"] as? String {
+                includeStrings = [includeString]
+            } else if let includeArray = json["include"] as? [String] {
+                includeStrings = includeArray
+            } else {
+                includeStrings = []
+            }
+
+            let includes = try includeStrings.map { include -> Spec in
+                let path = Path(include)
+                return try Spec(filename: path.lastComponent, basePath: basePath + relativePath, relativePath: path.parent())
+            }
+
+            self.relativePath = relativePath
+            self.jsonDictionary = json
+            self.subSpecs = includes
+        }
+
+        public func resolvedDictionary() -> JSONDictionary {
+            return jsonDictionary.merged(onto:
+                subSpecs
+                    .map { $0.resolvedDictionary() }
+                    .reduce([:]) { $1.merged(onto: $0) }
+            )
+        }
+    }
+}
+
+internal protocol SubSequenceConvertible: Sequence {
+
+    init(_ subsequence: SubSequence)
+}
+
+extension String: SubSequenceConvertible { }
+extension Substring: SubSequenceConvertible { }
+
+extension Dictionary where Key: StringProtocol, Key: SubSequenceConvertible, Value: Any {
+
+    func merged(onto other: Dictionary<Key, Value>) -> Dictionary<Key, Value> {
+        var merged = other
+
+        for (key, value) in self {
+            if key.hasSuffix(":REPLACE") {
+                let newKey = key[key.startIndex ..< key.index(key.endIndex, offsetBy: -8)]
+                merged[Key(newKey)] = value
+            } else if let dictionary = value as? Dictionary<Key, Value>, let base = merged[key] as? Dictionary<Key, Value> {
+                merged[key] = dictionary.merged(onto: base) as? Value
+            } else if let array = value as? [Any], let base = merged[key] as? [Any] {
+                merged[key] = (base + array) as? Value
+            } else {
+                merged[key] = value
+            }
+        }
+        return merged
+    }
+}