diff --git a/Package.swift b/Package.swift
index 15e1617..a88b736 100644
--- a/Package.swift
+++ b/Package.swift
@@ -7,7 +7,7 @@ import PackageDescription
 let package = Package(
     name: "AppStoreServerLibrary",
     platforms: [
-        .macOS(.v11), // And other server environments
+        .macOS(.v13), // And other server environments
     ],
     products: [
         .library(
@@ -18,7 +18,7 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-certificates.git", from: "1.0.0"),
         .package(url: "https://github.com/apple/swift-asn1.git", from: "1.1.0"),
         .package(url: "https://github.com/apple/swift-crypto.git", "1.0.0" ..< "4.0.0"),
-        .package(url: "https://github.com/vapor/jwt-kit.git", from: "4.0.0"),
+        .package(url: "https://github.com/vapor/jwt-kit.git", from: "5.0.0"),
         .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),
         .package(url: "https://github.com/apple/swift-nio", from: "2.0.0"),
         .package(url: "https://github.com/swift-server/async-http-client.git", from: "1.9.0"),
diff --git a/Sources/AppStoreServerLibrary/AppStoreServerAPIClient.swift b/Sources/AppStoreServerLibrary/AppStoreServerAPIClient.swift
index c1aff08..77a832f 100644
--- a/Sources/AppStoreServerLibrary/AppStoreServerAPIClient.swift
+++ b/Sources/AppStoreServerLibrary/AppStoreServerAPIClient.swift
@@ -76,7 +76,7 @@ public class AppStoreServerAPIClient {
             }
             
             var urlRequest = HTTPClientRequest(url: url.absoluteString)
-            let token = try generateToken()
+            let token = try await generateToken()
             urlRequest.headers.add(name: "User-Agent", value: AppStoreServerAPIClient.userAgent)
             urlRequest.headers.add(name: "Authorization", value: "Bearer \(token)")
             urlRequest.headers.add(name: "Accept", value: "application/json")
@@ -141,8 +141,8 @@ public class AppStoreServerAPIClient {
         }
     }
         
-    private func generateToken() throws -> String {
-        let signers = JWTSigners()
+    private func generateToken() async throws -> String {
+        let keys = JWTKeyCollection()
         let payload = AppStoreServerAPIJWT(
             exp: .init(value: Date().addingTimeInterval(5 * 60)), // 5 minutes
             iss: .init(value: self.issuerId),
@@ -150,9 +150,8 @@ public class AppStoreServerAPIClient {
             aud: .init(value: AppStoreServerAPIClient.appStoreConnectAudience),
             iat: .init(value: Date())
         )
-        let key: ECDSAKey = try ECDSAKey.private(pem: self.signingKey.pemRepresentation)
-        signers.use(.es256(key: key))
-        return try signers.sign(payload, typ: "JWT", kid: JWKIdentifier(stringLiteral: self.keyId))
+        try await keys.add(ecdsa: ECDSA.PrivateKey<P256>(backing: signingKey))
+        return try await keys.sign(payload, header: ["typ": "JWT", "kid": .string(self.keyId)])
     }
     
     ///Uses a subscription’s product identifier to extend the renewal date for all of its eligible active subscribers.
@@ -333,7 +332,8 @@ public class AppStoreServerAPIClient {
         var bid: String
         var aud: AudienceClaim
         var iat: IssuedAtClaim
-        func verify(using signer: JWTSigner) throws {
+
+        func verify(using algorithm: some JWTAlgorithm) async throws {
             fatalError("Do not attempt to locally verify a JWT")
         }
     }
diff --git a/Sources/AppStoreServerLibrary/ChainVerifier.swift b/Sources/AppStoreServerLibrary/ChainVerifier.swift
index 3c0fed3..de39f3d 100644
--- a/Sources/AppStoreServerLibrary/ChainVerifier.swift
+++ b/Sources/AppStoreServerLibrary/ChainVerifier.swift
@@ -70,9 +70,9 @@ struct ChainVerifier {
                     return VerificationResult.invalid(VerificationError.VERIFICATION_FAILURE)
                 }
                 // Verify using Vapor
-                let signers = JWTSigners()
-                try signers.use(.es256(key: .public(pem: publicKey.pemRepresentation)))
-                let verifiedBody: VerificationResult<VaporBody> = try VerificationResult<VaporBody>.valid(signers.verify(signedData))
+                let keys = JWTKeyCollection()
+                await keys.add(ecdsa: try ECDSA.PublicKey<P256>(backing: publicKey))
+                let verifiedBody: VerificationResult<VaporBody> = try await VerificationResult<VaporBody>.valid(keys.verify(signedData))
                 switch verifiedBody {
                     case .invalid(_):
                         return VerificationResult.invalid(VerificationError.VERIFICATION_FAILURE)
@@ -100,8 +100,8 @@ struct ChainVerifier {
     }
 }
 
-class VaporBody : JWTPayload {
-    func verify(using signer: JWTKit.JWTSigner) throws {
+struct VaporBody : JWTPayload {
+    func verify(using algorithm: some JWTAlgorithm) async throws {
         // No-op
     }
 }
diff --git a/Tests/AppStoreServerLibraryTests/TestingUtility.swift b/Tests/AppStoreServerLibraryTests/TestingUtility.swift
index fb7a58c..e33f851 100644
--- a/Tests/AppStoreServerLibraryTests/TestingUtility.swift
+++ b/Tests/AppStoreServerLibraryTests/TestingUtility.swift
@@ -40,19 +40,19 @@ public class TestingUtility {
     public static func createSignedDataFromJson(_ path: String) -> String {
         let payload = readFile(path)
         let signingKey = Crypto.P256.Signing.PrivateKey()
-        let signer: JWTSigner = try! .es256(key: .private(pem: signingKey.pemRepresentation))
         
         let header = JWTHeader(alg: "ES256")
 
         let encoder = JSONEncoder()
         let headerData = try! encoder.encode(header)
-        let encodedHeader = headerData.base64EncodedString()
+        let encodedHeader = base64ToBase64URL(headerData.base64EncodedString())
 
-        let encodedPayload = payload.data(using: .utf8)!.base64EncodedString()
-
-        let signature = try! signer.algorithm.sign("\(encodedHeader).\(encodedPayload)".data(using: .utf8)!)
+        let encodedPayload = base64ToBase64URL(payload.data(using: .utf8)!.base64EncodedString())
+        
+        var signingInput = "\(encodedHeader).\(encodedPayload)"
+        let signature = try! signingInput.withUTF8 { try signingKey.signature(for: $0) }
 
-        return "\(base64ToBase64URL(encodedHeader)).\(base64ToBase64URL(encodedPayload)).\(base64ToBase64URL(Data(signature).base64EncodedString()))";
+        return "\(signingInput).\(base64ToBase64URL(signature.rawRepresentation.base64EncodedString()))";
     }
     
     private static func base64ToBase64URL(_ encodedString: String) -> String {