diff --git a/endpoint/endpoint.go b/endpoint/endpoint.go
index 3c0187935..cc3183d73 100644
--- a/endpoint/endpoint.go
+++ b/endpoint/endpoint.go
@@ -159,6 +159,7 @@ func NewEndpointWithTTL(dnsName, recordType string, ttl TTL, targets ...string)
 	}
 }
 
+// WithSetIdentifier applies the given set identifier to the endpoint.
 func (e *Endpoint) WithSetIdentifier(setIdentifier string) *Endpoint {
 	e.SetIdentifier = setIdentifier
 	return e
diff --git a/provider/aws_test.go b/provider/aws_test.go
index 199154de4..14791ee39 100644
--- a/provider/aws_test.go
+++ b/provider/aws_test.go
@@ -184,11 +184,11 @@ func (r *Route53APIStub) ChangeResourceRecordSetsWithContext(ctx context.Context
 			change.ResourceRecordSet.AliasTarget.DNSName = aws.String(wildcardEscape(ensureTrailingDot(aws.StringValue(change.ResourceRecordSet.AliasTarget.DNSName))))
 		}
 
-		setId := ""
+		setID := ""
 		if change.ResourceRecordSet.SetIdentifier != nil {
-			setId = aws.StringValue(change.ResourceRecordSet.SetIdentifier)
+			setID = aws.StringValue(change.ResourceRecordSet.SetIdentifier)
 		}
-		key := aws.StringValue(change.ResourceRecordSet.Name) + "::" + aws.StringValue(change.ResourceRecordSet.Type) + "::" + setId
+		key := aws.StringValue(change.ResourceRecordSet.Name) + "::" + aws.StringValue(change.ResourceRecordSet.Type) + "::" + setID
 		switch aws.StringValue(change.Action) {
 		case route53.ChangeActionCreate:
 			if _, found := recordSets[key]; found {
diff --git a/provider/cloudflare_test.go b/provider/cloudflare_test.go
index 88469d707..cc359b391 100644
--- a/provider/cloudflare_test.go
+++ b/provider/cloudflare_test.go
@@ -173,9 +173,9 @@ func (m *mockCloudFlareClient) ListZones(zoneID ...string) ([]cloudflare.Zone, e
 
 	result := []cloudflare.Zone{}
 
-	for zoneId, zoneName := range m.Zones {
+	for zoneID, zoneName := range m.Zones {
 		result = append(result, cloudflare.Zone{
-			ID:   zoneId,
+			ID:   zoneID,
 			Name: zoneName,
 		})
 	}
diff --git a/provider/vultr.go b/provider/vultr.go
index 869ace7c3..c039cb405 100644
--- a/provider/vultr.go
+++ b/provider/vultr.go
@@ -36,6 +36,7 @@ const (
 	vultrTTL    = 3600
 )
 
+// VultrProvider is an implementation of Provider for Vultr DNS.
 type VultrProvider struct {
 	client govultr.Client
 
@@ -43,6 +44,7 @@ type VultrProvider struct {
 	DryRun       bool
 }
 
+// VultrChanges differentiates between ChangActions.
 type VultrChanges struct {
 	Action string
 
@@ -78,6 +80,7 @@ func (p *VultrProvider) Zones(ctx context.Context) ([]govultr.DNSDomain, error)
 	return zones, nil
 }
 
+// Records returns the list of records.
 func (p *VultrProvider) Records(ctx context.Context) ([]*endpoint.Endpoint, error) {
 	zones, err := p.Zones(ctx)
 	if err != nil {
@@ -201,6 +204,7 @@ func (p *VultrProvider) submitChanges(ctx context.Context, changes []*VultrChang
 	return nil
 }
 
+// ApplyChanges applies a given set of changes in a given zone.
 func (p *VultrProvider) ApplyChanges(ctx context.Context, changes *plan.Changes) error {
 	combinedChanges := make([]*VultrChanges, 0, len(changes.Create)+len(changes.UpdateNew)+len(changes.Delete))
 
diff --git a/source/routegroup.go b/source/routegroup.go
index 3a91e02a1..e74b0875c 100644
--- a/source/routegroup.go
+++ b/source/routegroup.go
@@ -37,7 +37,8 @@ import (
 )
 
 const (
-	defaultIdleConnTimeout       = 30 * time.Second
+	defaultIdleConnTimeout = 30 * time.Second
+	// DefaultRoutegroupVersion is the default version for route groups.
 	DefaultRoutegroupVersion     = "zalando.org/v1"
 	routeGroupListResource       = "/apis/%s/routegroups"
 	routeGroupNamespacedResource = "/apis/%s/namespaces/%s/routegroups"