diff --git a/create_topics_request.go b/create_topics_request.go
index 7bad5427e..8382d17c2 100644
--- a/create_topics_request.go
+++ b/create_topics_request.go
@@ -5,10 +5,14 @@ import (
 )
 
 type CreateTopicsRequest struct {
+	// Version defines the protocol version to use for encode and decode
 	Version int16
-
+	// TopicDetails contains the topics to create.
 	TopicDetails map[string]*TopicDetail
-	Timeout      time.Duration
+	// Timeout contains how long to wait before timing out the request.
+	Timeout time.Duration
+	// ValidateOnly if true, check that the topics can be created as specified,
+	// but don't create anything.
 	ValidateOnly bool
 }
 
@@ -103,10 +107,19 @@ func (c *CreateTopicsRequest) requiredVersion() KafkaVersion {
 }
 
 type TopicDetail struct {
-	NumPartitions     int32
+	// NumPartitions contains the number of partitions to create in the topic, or
+	// -1 if we are either specifying a manual partition assignment or using the
+	// default partitions.
+	NumPartitions int32
+	// ReplicationFactor contains the number of replicas to create for each
+	// partition in the topic, or -1 if we are either specifying a manual
+	// partition assignment or using the default replication factor.
 	ReplicationFactor int16
+	// ReplicaAssignment contains the manual partition assignment, or the empty
+	// array if we are using automatic assignment.
 	ReplicaAssignment map[int32][]int32
-	ConfigEntries     map[string]*string
+	// ConfigEntries contains the custom topic configurations to set.
+	ConfigEntries map[string]*string
 }
 
 func (t *TopicDetail) encode(pe packetEncoder) error {
diff --git a/create_topics_response.go b/create_topics_response.go
index d8c9a174e..85bd4c0b9 100644
--- a/create_topics_response.go
+++ b/create_topics_response.go
@@ -6,9 +6,13 @@ import (
 )
 
 type CreateTopicsResponse struct {
-	Version      int16
+	// Version defines the protocol version to use for encode and decode
+	Version int16
+	// ThrottleTime contains the duration for which the request was throttled due
+	// to a quota violation, or zero if the request did not violate any quota.
 	ThrottleTime time.Duration
-	TopicErrors  map[string]*TopicError
+	// TopicErrors contains a map of any errors for the topics we tried to create.
+	TopicErrors map[string]*TopicError
 }
 
 func (c *CreateTopicsResponse) encode(pe packetEncoder) error {
diff --git a/join_group_request.go b/join_group_request.go
index b574ce475..3ab69c498 100644
--- a/join_group_request.go
+++ b/join_group_request.go
@@ -1,7 +1,9 @@
 package sarama
 
 type GroupProtocol struct {
-	Name     string
+	// Name contains the protocol name.
+	Name string
+	// Metadata contains the protocol metadata.
 	Metadata []byte
 }
 
@@ -25,14 +27,30 @@ func (p *GroupProtocol) encode(pe packetEncoder) (err error) {
 }
 
 type JoinGroupRequest struct {
-	Version               int16
-	GroupId               string
-	SessionTimeout        int32
-	RebalanceTimeout      int32
-	MemberId              string
-	GroupInstanceId       *string
-	ProtocolType          string
-	GroupProtocols        map[string][]byte // deprecated; use OrderedGroupProtocols
+	// Version defines the protocol version to use for encode and decode
+	Version int16
+	// GroupId contains the group identifier.
+	GroupId string
+	// SessionTimeout specifies that the coordinator should consider the consumer
+	// dead if it receives no heartbeat after this timeout in milliseconds.
+	SessionTimeout int32
+	// RebalanceTimeout contains the maximum time in milliseconds that the
+	// coordinator will wait for each member to rejoin when rebalancing the
+	// group.
+	RebalanceTimeout int32
+	// MemberId contains the member id assigned by the group coordinator.
+	MemberId string
+	// GroupInstanceId contains the unique identifier of the consumer instance
+	// provided by end user.
+	GroupInstanceId *string
+	// ProtocolType contains the unique name the for class of protocols
+	// implemented by the group we want to join.
+	ProtocolType string
+	// GroupProtocols contains the list of protocols that the member supports.
+	// deprecated; use OrderedGroupProtocols
+	GroupProtocols map[string][]byte
+	// OrderedGroupProtocols contains an ordered list of protocols that the member
+	// supports.
 	OrderedGroupProtocols []*GroupProtocol
 }
 
diff --git a/join_group_response.go b/join_group_response.go
index 76645242e..643fddc6b 100644
--- a/join_group_response.go
+++ b/join_group_response.go
@@ -3,20 +3,33 @@ package sarama
 import "time"
 
 type JoinGroupResponse struct {
-	Version       int16
-	ThrottleTime  int32
-	Err           KError
-	GenerationId  int32
+	// Version defines the protocol version to use for encode and decode
+	Version int16
+	// ThrottleTime contains the duration for which the request was throttled due
+	// to a quota violation, or zero if the request did not violate any quota.
+	ThrottleTime int32
+	// Err contains the error code, or 0 if there was no error.
+	Err KError
+	// GenerationId contains the generation ID of the group.
+	GenerationId int32
+	// GroupProtocol contains the group protocol selected by the coordinator.
 	GroupProtocol string
-	LeaderId      string
-	MemberId      string
-	Members       []GroupMember
+	// LeaderId contains the leader of the group.
+	LeaderId string
+	// MemberId contains the member ID assigned by the group coordinator.
+	MemberId string
+	// Members contains the per-group-member information.
+	Members []GroupMember
 }
 
 type GroupMember struct {
-	MemberId        string
+	// MemberId contains the group member ID.
+	MemberId string
+	// GroupInstanceId contains the unique identifier of the consumer instance
+	// provided by end user.
 	GroupInstanceId *string
-	Metadata        []byte
+	// Metadata contains the group member metadata.
+	Metadata []byte
 }
 
 func (r *JoinGroupResponse) GetMembers() (map[string]ConsumerGroupMemberMetadata, error) {