diff --git a/src/src/PEPTransport.h b/src/src/PEPTransport.h
new file mode 100644
index 0000000..b53c114
--- /dev/null
+++ b/src/src/PEPTransport.h
@@ -0,0 +1,79 @@
+#import <Foundation/Foundation.h>
+
+@import PEPObjCTypes_macOS;
+
+@class PEPTransportConfig;
+@class PEPSession;
+@class PEPTransport;
+@class PEPMessage;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@protocol PEPCCSendResultDelegate <NSObject>
+
+- (BOOL)signalSendMessageResultWithTransportID:(PEPCCTransportID)transportID
+                                     messageID:(NSString *)messageID
+                                       address:(NSString *)address
+                                    statusCode:(PEPCCTransportStatusCode *)statusCode
+                                         error:(NSError * _Nullable * _Nullable)error;
+@end
+
+@protocol PEPCCIncomingMessageDelegate <NSObject>
+
+- (BOOL)signalNewIncomingMessageWithTransportID:(PEPCCTransportID)transportID
+                                     statusCode:(PEPCCTransportStatusCode *)statusCode
+                                          error:(NSError * _Nullable * _Nullable)error;
+@end
+
+@protocol PEPCCStatusChangeDelegate <NSObject>
+
+- (BOOL)statusChangedWithTransportID:(PEPCCTransportID)transportID
+                          statusCode:(PEPCCTransportStatusCode *)statusCode
+                               error:(NSError * _Nullable * _Nullable)error;
+@end
+
+/// Idea in a nutshell:
+/// - Init with callbacks and callbackExecutionType
+/// - configure
+/// - startup
+/// - listen to status changes (e.g. connected aka "PEPCCTransportStatusCodeReady"
+/// - use it:
+///     - send message
+///     - listen to- and handle sendMessageResult (e.g. done sending aka "PEPCCTransportStatusCodeMessageDelivered")
+///     - listen to newIncommingMessage delegate
+///         - call nextMessage to get it
+/// shutdown
+@protocol PEPTransport <NSObject>
+
+- (instancetype)init;
+
+/// Convenience initializer.
+- (_Nullable instancetype)initWithChangeDelegate:(id<PEPCCStatusChangeDelegate> _Nullable)statusChangeDelegate
+                        signalSendResultDelegate:(id<PEPCCSendResultDelegate> _Nullable)signalSendResultDelegate
+                   signalIncomingMessageDelegate:(id<PEPCCIncomingMessageDelegate> _Nullable)signalIncomingMessageDelegate
+                           callbackExecutionType:(PEPCCCallbackExcecutionType)callbackExecutionType
+                                           error:(NSError * _Nullable * _Nullable)error;
+
+- (BOOL)configure:(PEPTransport * _Nullable)pEptransport
+       withConfig:(PEPTransportConfig *)config
+transportStatusCode:(out PEPCCTransportStatusCode * _Nullable)tsc
+            error:(NSError * _Nullable * _Nullable)error;
+
+- (BOOL)startup:(PEPTransport * _Nullable)pEptransport
+transportStatusCode:(out PEPCCTransportStatusCode*)tsc
+          error:(NSError * _Nullable * _Nullable)error;
+
+- (BOOL)shutdown:(PEPTransport * _Nullable)pEptransport
+transportStatusCode:(out PEPCCTransportStatusCode * _Nullable)tsc
+           error:(NSError * _Nullable * _Nullable)error;
+
+- (BOOL)sendMessage:(PEPMessage *)msg pEpSession:(PEPSession * _Nullable)pEpSession
+transportStatusCode:(out PEPCCTransportStatusCode * _Nullable)tsc
+              error:(NSError * _Nullable * _Nullable)error;
+
+- (PEPMessage * _Nullable)nextMessageWithPEPSession:(PEPSession * _Nullable)pEpsession
+                                transportStatusCode:(out PEPCCTransportStatusCode * _Nullable)tsc
+                                              error:(NSError * _Nullable * _Nullable)error;
+@end
+
+NS_ASSUME_NONNULL_END