diff --git a/include/QtCrypto/qca_basic.h b/include/QtCrypto/qca_basic.h
index 55ff0405..09b5ddc0 100644
--- a/include/QtCrypto/qca_basic.h
+++ b/include/QtCrypto/qca_basic.h
@@ -36,6 +36,13 @@
 
 namespace QCA {
 
+/**
+   \defgroup UserAPI QCA user API
+
+   This is the main set of QCA classes, intended for use
+   in standard applications.
+*/
+/*@{*/
 /**
    \class Random qca_basic.h QtCrypto
 
@@ -888,7 +895,7 @@ public:
 	*/
 	explicit PBKDF2(const QString &algorithm = "sha1", const QString &provider = QString()) : KeyDerivationFunction(withAlgorithm("pbkdf2", algorithm), provider) {}
 };
-
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qca_cert.h b/include/QtCrypto/qca_cert.h
index 68412869..32d10cac 100644
--- a/include/QtCrypto/qca_cert.h
+++ b/include/QtCrypto/qca_cert.h
@@ -47,6 +47,10 @@ class CRL;
 class CertificateCollection;
 class CertificateChain;
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    Certificate Request Format
 */
@@ -2546,7 +2550,7 @@ private:
 	friend class Private;
 	Private *d;
 };
-
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qca_core.h b/include/QtCrypto/qca_core.h
index 90f5a530..ef32e8b5 100644
--- a/include/QtCrypto/qca_core.h
+++ b/include/QtCrypto/qca_core.h
@@ -73,6 +73,10 @@ class KeyStoreInfo;
 class KeyStoreManager;
 class Logger;
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    Convenience representation for the plugin providers
 
@@ -1602,6 +1606,7 @@ private:
 	friend class Private;
 	Private *d;
 };
+/*@}*/
 
 }
 
diff --git a/include/QtCrypto/qca_keystore.h b/include/QtCrypto/qca_keystore.h
index b4df95b1..7b58a0d7 100644
--- a/include/QtCrypto/qca_keystore.h
+++ b/include/QtCrypto/qca_keystore.h
@@ -41,6 +41,10 @@ class KeyStoreTracker;
 class KeyStoreManagerPrivate;
 class KeyStorePrivate;
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    \class KeyStoreEntry qca_keystore.h QtCrypto
 
@@ -765,7 +769,7 @@ private:
 	static void scan();
 	static void shutdown();
 };
-
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qca_publickey.h b/include/QtCrypto/qca_publickey.h
index 3fdb8f87..a6a0f15e 100644
--- a/include/QtCrypto/qca_publickey.h
+++ b/include/QtCrypto/qca_publickey.h
@@ -47,6 +47,10 @@ class DSAPrivateKey;
 class DHPublicKey;
 class DHPrivateKey;
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    Encryption algorithms
 */
@@ -1420,7 +1424,7 @@ public:
 	*/
 	BigInteger x() const;
 };
-
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qca_securelayer.h b/include/QtCrypto/qca_securelayer.h
index 13d63e5b..7172dd5c 100644
--- a/include/QtCrypto/qca_securelayer.h
+++ b/include/QtCrypto/qca_securelayer.h
@@ -38,6 +38,10 @@
 
 namespace QCA {
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    Specify the lower-bound for acceptable TLS/SASL security layers
 
@@ -1172,7 +1176,7 @@ private:
 	friend class Private;
 	Private *d;
 };
-
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qca_securemessage.h b/include/QtCrypto/qca_securemessage.h
index 6931c3a1..6406957b 100644
--- a/include/QtCrypto/qca_securemessage.h
+++ b/include/QtCrypto/qca_securemessage.h
@@ -41,6 +41,10 @@ class QDateTime;
 
 namespace QCA {
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 class SecureMessageSystem;
 
 /**
@@ -902,6 +906,7 @@ private:
 	class Private;
 	Private *d;
 };
+/*@}*/
 
 }
 
diff --git a/include/QtCrypto/qca_support.h b/include/QtCrypto/qca_support.h
index 830485f1..982b43b7 100644
--- a/include/QtCrypto/qca_support.h
+++ b/include/QtCrypto/qca_support.h
@@ -49,6 +49,10 @@
 
 namespace QCA {
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    Convenience method to determine the return type of a method
 
@@ -93,6 +97,8 @@ myTypeName = QCA::methodReturnType( testClass.metaObject(), QByteArray( "boolMet
    argument types.
 
    \sa QMetaType for more information on the Qt meta type system.
+
+   \relates SyncThread
 */
 
 QCA_EXPORT QByteArray methodReturnType(const QMetaObject *obj, const QByteArray &method, const QList<QByteArray> argTypes);
@@ -135,9 +141,14 @@ ret = QCA::invokeMethodWithVariants( testClass1, QByteArray( "boolMethod" ), arg
    \param type the type of connection to use
 
    \return true if the call succeeded, otherwise false
+
+   \relates SyncThread
 */
 QCA_EXPORT bool invokeMethodWithVariants(QObject *obj, const QByteArray &method, const QVariantList &args, QVariant *ret, Qt::ConnectionType type = Qt::AutoConnection);
 
+/**
+   Convenience class to synchronize a thread
+*/
 class QCA_EXPORT SyncThread : public QThread
 {
 	Q_OBJECT
@@ -582,7 +593,7 @@ private:
 
 	QString m_name;
 };
-
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qca_textfilter.h b/include/QtCrypto/qca_textfilter.h
index f6d1fd8d..c1d2805f 100644
--- a/include/QtCrypto/qca_textfilter.h
+++ b/include/QtCrypto/qca_textfilter.h
@@ -35,7 +35,10 @@
 #include "qca_core.h"
 
 namespace QCA {
-
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    \class TextFilter qca_textfilter.h QtCrypto
 
@@ -310,7 +313,7 @@ private:
 	class Private;
 	Private *d;
 };
-
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qca_tools.h b/include/QtCrypto/qca_tools.h
index 06c3c274..ada581da 100644
--- a/include/QtCrypto/qca_tools.h
+++ b/include/QtCrypto/qca_tools.h
@@ -44,6 +44,10 @@ class QString;
 class QByteArray;
 class QTextStream;
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    Allocate a block of memory from the secure memory pool.
 
@@ -71,9 +75,13 @@ QCA_EXPORT void qca_secure_free(void *p);
    \param bytes the new size that is required.
 */
 QCA_EXPORT void *qca_secure_realloc(void *p, int bytes);
-
+/*@}*/
 namespace QCA {
 
+/**
+   \addtogroup UserAPI
+*/
+/*@{*/
 /**
    \class MemoryRegion qca_tools.h QtCrypto
 
@@ -776,6 +784,7 @@ private:
 */
 QCA_EXPORT QTextStream &operator<<(QTextStream &stream, const BigInteger &b);
 
+/*@}*/
 }
 
 #endif
diff --git a/include/QtCrypto/qcaprovider.h b/include/QtCrypto/qcaprovider.h
index 00d3d3e3..2297eeee 100644
--- a/include/QtCrypto/qcaprovider.h
+++ b/include/QtCrypto/qcaprovider.h
@@ -42,6 +42,14 @@
 
 #include <limits>
 
+/**
+   \defgroup ProviderAPI QCA provider API
+
+   This group of classes and functions is not normally needed 
+   by application writers, but can be used to extend QCA if
+   required
+*/
+/*@{*/
 /**
    Provider plugin base class
 
@@ -77,11 +85,17 @@ public:
 	*/
 	virtual QCA::Provider *createProvider() = 0;
 };
+/*@}*/
 
 Q_DECLARE_INTERFACE(QCAPlugin, "com.affinix.qca.Plugin/1.0")
 
 namespace QCA {
 
+/**
+   \addtogroup ProviderAPI
+*/
+/*@{*/
+
 /**
    Random provider
 
@@ -1998,6 +2012,9 @@ public:
 	virtual MessageContext *createMessage() = 0;
 };
 
+/*@}*/
+
 }
 
+
 #endif