diff --git a/app/model/CampaignInformation.scala b/app/model/CampaignInformation.scala
index 9d408b82..f86ac271 100644
--- a/app/model/CampaignInformation.scala
+++ b/app/model/CampaignInformation.scala
@@ -18,7 +18,7 @@ case class CampaignInformation(campaignType: String) {
 
 object CampaignInformation {
 
-  implicit val trackingFormat = Jsonx.formatCaseClass[CampaignInformation]
+  implicit val trackingFormat: OFormat[CampaignInformation] = Jsonx.formatCaseClass[CampaignInformation]
 
   def apply(thriftCampaignInformation: ThriftCampaignInformation): CampaignInformation =
     CampaignInformation(
diff --git a/app/model/ClientConfig.scala b/app/model/ClientConfig.scala
index c224a9dd..2f6e0c6a 100644
--- a/app/model/ClientConfig.scala
+++ b/app/model/ClientConfig.scala
@@ -2,6 +2,7 @@ package model
 
 import ai.x.play.json.Encoders.encoder
 import ai.x.play.json.Jsonx
+import play.api.libs.json.OFormat
 
 case class ClientConfig(username: String,
                         capiUrl: String,
@@ -15,5 +16,5 @@ case class ClientConfig(username: String,
                        )
 
 object ClientConfig {
-  implicit val clientConfigFormat = Jsonx.formatCaseClass[ClientConfig]
+  implicit val clientConfigFormat: OFormat[ClientConfig] = Jsonx.formatCaseClass[ClientConfig]
 }
diff --git a/app/model/ContributorInformation.scala b/app/model/ContributorInformation.scala
index cc70b26d..bc9f46ca 100644
--- a/app/model/ContributorInformation.scala
+++ b/app/model/ContributorInformation.scala
@@ -36,7 +36,7 @@ case class ContributorInformation(
 
 object ContributorInformation {
 
-  implicit val contributorInformationFormat = Jsonx.formatCaseClass[ContributorInformation]
+  implicit val contributorInformationFormat: OFormat[ContributorInformation] = Jsonx.formatCaseClass[ContributorInformation]
 
   def apply(thriftContributorInformation: ThriftContributorInformation): ContributorInformation =
     ContributorInformation(
diff --git a/app/model/EditionalisedPage.scala b/app/model/EditionalisedPage.scala
index e98b892d..68e947bd 100644
--- a/app/model/EditionalisedPage.scala
+++ b/app/model/EditionalisedPage.scala
@@ -3,6 +3,7 @@ package model
 import ai.x.play.json.Jsonx
 import ai.x.play.json.Encoders.encoder
 import com.gu.tagmanagement.{EditionalisedPage => ThriftEditionalisedPage}
+import play.api.libs.json.OFormat
 
 case class EditionalisedPage(path: String, pageId: Long) {
   def asThift = ThriftEditionalisedPage(path, pageId)
@@ -10,7 +11,7 @@ case class EditionalisedPage(path: String, pageId: Long) {
 
 object EditionalisedPage {
 
-  implicit val editionalisedPageFormat = Jsonx.formatCaseClass[EditionalisedPage]
+  implicit val editionalisedPageFormat: OFormat[EditionalisedPage] = Jsonx.formatCaseClass[EditionalisedPage]
 
   def apply(thriftEditionalisedPage: ThriftEditionalisedPage): EditionalisedPage =
     EditionalisedPage(thriftEditionalisedPage.path, thriftEditionalisedPage.pageId)
diff --git a/app/model/ExternalReferenceType.scala b/app/model/ExternalReferenceType.scala
index 6a85a04b..784ccdf5 100644
--- a/app/model/ExternalReferenceType.scala
+++ b/app/model/ExternalReferenceType.scala
@@ -10,6 +10,7 @@ import play.api.libs.json.{Format, JsPath, JsValue, Json}
 import com.gu.tagmanagement.{Section => ThriftSection}
 
 import scala.util.control.NonFatal
+import play.api.libs.json.OFormat
 
 case class ExternalReferenceType (
                     typeName: String,
@@ -20,7 +21,7 @@ case class ExternalReferenceType (
 
 object ExternalReferenceType extends Logging {
 
-  implicit val sectionFormat = Jsonx.formatCaseClass[ExternalReferenceType]
+  implicit val sectionFormat: OFormat[ExternalReferenceType] = Jsonx.formatCaseClass[ExternalReferenceType]
 
   def fromItem(item: Item) = try{
     Json.parse(item.toJSON).as[ExternalReferenceType]
diff --git a/app/model/HyperMedia.scala b/app/model/HyperMedia.scala
index 241f79e0..4e05c179 100644
--- a/app/model/HyperMedia.scala
+++ b/app/model/HyperMedia.scala
@@ -4,7 +4,7 @@ import services.Config.conf
 
 
 case class LinkEntity(rel: String, href: String)
-object LinkEntity { implicit val jsonWrites = Json.writes[LinkEntity] }
+object LinkEntity { implicit val jsonWrites: OWrites[LinkEntity] = Json.writes[LinkEntity] }
 
 case class EmbeddedEntity[T](uri: String,
                              data: Option[T] = None,
@@ -59,7 +59,7 @@ object CollectionResponse {
 case class EmptyResponse(links: Option[List[LinkEntity]] = None) {
   def addLink(rel: String, href: String) = copy(links = Some(LinkEntity(rel, href) :: (links getOrElse Nil)))
 }
-object EmptyResponse { implicit val jsonWrites = Json.writes[EmptyResponse] }
+object EmptyResponse { implicit val jsonWrites: OWrites[EmptyResponse] = Json.writes[EmptyResponse] }
 
 object HyperMediaHelpers {
   def tagUri(id: Long): String = s"https://tagmanager.${conf.pandaDomain}/hyper/tags/${id}"
diff --git a/app/model/ImageAsset.scala b/app/model/ImageAsset.scala
index ea4c0af0..3981372e 100644
--- a/app/model/ImageAsset.scala
+++ b/app/model/ImageAsset.scala
@@ -3,6 +3,7 @@ package model
 import ai.x.play.json.Jsonx
 import ai.x.play.json.Encoders.encoder
 import com.gu.tagmanagement.{ImageAsset => ThriftImageAsset}
+import play.api.libs.json.OFormat
 
 case class ImageAsset(imageUrl: String, width: Long, height: Long, mimeType: String) {
   def asThrift = ThriftImageAsset(imageUrl, width, height, mimeType)
@@ -15,7 +16,7 @@ case class ImageAsset(imageUrl: String, width: Long, height: Long, mimeType: Str
 }
 
 object ImageAsset {
-  implicit val imageAssetFormat = Jsonx.formatCaseClass[ImageAsset]
+  implicit val imageAssetFormat: OFormat[ImageAsset] = Jsonx.formatCaseClass[ImageAsset]
 
   def apply(thriftImageAsset: ThriftImageAsset): ImageAsset = ImageAsset(
     imageUrl = thriftImageAsset.imageUrl,
diff --git a/app/model/PaidContentInformation.scala b/app/model/PaidContentInformation.scala
index e93d3dc7..e743c24b 100644
--- a/app/model/PaidContentInformation.scala
+++ b/app/model/PaidContentInformation.scala
@@ -3,6 +3,7 @@ package model
 import ai.x.play.json.Jsonx
 import ai.x.play.json.Encoders.encoder
 import com.gu.tagmanagement.{PaidContentInformation => ThriftPaidContentInformation}
+import play.api.libs.json.OFormat
 
 case class PaidContentInformation(paidContentType: String, campaignColour: Option[String] = None) {
 
@@ -19,7 +20,7 @@ case class PaidContentInformation(paidContentType: String, campaignColour: Optio
 
 object PaidContentInformation {
 
-  implicit val paidContentInformationFormat = Jsonx.formatCaseClass[PaidContentInformation]
+  implicit val paidContentInformationFormat: OFormat[PaidContentInformation] = Jsonx.formatCaseClass[PaidContentInformation]
 
   def apply(thriftPaidContentInformation: ThriftPaidContentInformation): PaidContentInformation =
     PaidContentInformation(
diff --git a/app/model/PublicationInformation.scala b/app/model/PublicationInformation.scala
index 8d8abfdf..c0e735ad 100644
--- a/app/model/PublicationInformation.scala
+++ b/app/model/PublicationInformation.scala
@@ -24,7 +24,7 @@ case class PublicationInformation(
 
 object PublicationInformation {
 
-  implicit val publicationInformationFormat = Jsonx.formatCaseClassUseDefaults[PublicationInformation]
+  implicit val publicationInformationFormat: OFormat[PublicationInformation] = Jsonx.formatCaseClassUseDefaults[PublicationInformation]
 
   def apply(thriftPublicationInformation: ThriftPublicationInformation): PublicationInformation =
     PublicationInformation(
diff --git a/app/model/Reference.scala b/app/model/Reference.scala
index bf2d76d3..affc64d4 100644
--- a/app/model/Reference.scala
+++ b/app/model/Reference.scala
@@ -25,7 +25,7 @@ case class Reference(`type`: String, value: String, capiType: Option[String]) {
 
 object Reference {
 
-  implicit val referenceFormat = Jsonx.formatCaseClass[Reference]
+  implicit val referenceFormat: OFormat[Reference] = Jsonx.formatCaseClass[Reference]
 
   def apply(thriftReference: ThriftReference): Reference = Reference(thriftReference.`type`, thriftReference.value, thriftReference.capiType)
 
diff --git a/app/model/Sponsorship.scala b/app/model/Sponsorship.scala
index 82347855..53e9d59e 100644
--- a/app/model/Sponsorship.scala
+++ b/app/model/Sponsorship.scala
@@ -99,7 +99,7 @@ case class DenormalisedSponsorship (
 
 object DenormalisedSponsorship {
 
-  implicit val denormalisedSponsorshipFormat = Jsonx.formatCaseClass[DenormalisedSponsorship]
+  implicit val denormalisedSponsorshipFormat: OFormat[DenormalisedSponsorship] = Jsonx.formatCaseClass[DenormalisedSponsorship]
 
   def apply(s: Sponsorship): DenormalisedSponsorship = {
     new DenormalisedSponsorship(
diff --git a/app/model/Tag.scala b/app/model/Tag.scala
index a95cd810..b4028fda 100644
--- a/app/model/Tag.scala
+++ b/app/model/Tag.scala
@@ -248,7 +248,7 @@ case class DenormalisedTag (
 
 object DenormalisedTag{
 
-  implicit val tagFormat = Jsonx.formatCaseClassUseDefaults[DenormalisedTag]
+  implicit val tagFormat: OFormat[DenormalisedTag] = Jsonx.formatCaseClassUseDefaults[DenormalisedTag]
 
   def apply(t: Tag): DenormalisedTag = DenormalisedTag(
     id = t.id,
diff --git a/app/model/TagSearchResult.scala b/app/model/TagSearchResult.scala
index 5f988797..4b9c6eb0 100644
--- a/app/model/TagSearchResult.scala
+++ b/app/model/TagSearchResult.scala
@@ -2,9 +2,10 @@ package model
 
 import ai.x.play.json.Jsonx
 import ai.x.play.json.Encoders.encoder
+import play.api.libs.json.OFormat
 
 case class TagSearchResult(tags: List[Tag], count: Int)
 
 object TagSearchResult {
-  implicit val tagSearchResultFormat = Jsonx.formatCaseClassUseDefaults[TagSearchResult]
+  implicit val tagSearchResultFormat: OFormat[TagSearchResult] = Jsonx.formatCaseClassUseDefaults[TagSearchResult]
 }
diff --git a/app/model/TrackingInformation.scala b/app/model/TrackingInformation.scala
index 1196f853..b13f239d 100644
--- a/app/model/TrackingInformation.scala
+++ b/app/model/TrackingInformation.scala
@@ -18,7 +18,7 @@ case class TrackingInformation(trackingType: String) {
 
 object TrackingInformation {
 
-  implicit val trackingFormat = Jsonx.formatCaseClass[TrackingInformation]
+  implicit val trackingFormat: OFormat[TrackingInformation] = Jsonx.formatCaseClass[TrackingInformation]
 
   def apply(thriftTrackingInformation: ThriftTrackingInformation): TrackingInformation =
     TrackingInformation(
diff --git a/app/model/command/BatchTagCommand.scala b/app/model/command/BatchTagCommand.scala
index f2509e9e..79f57674 100644
--- a/app/model/command/BatchTagCommand.scala
+++ b/app/model/command/BatchTagCommand.scala
@@ -7,6 +7,7 @@ import ai.x.play.json.Encoders.encoder
 import repositories._
 
 import scala.concurrent.{Future, ExecutionContext}
+import play.api.libs.json.OFormat
 
 case class BatchTagCommand(contentIds: List[String], toAddToTop: Option[Long], toAddToBottom: List[Long], toRemove: List[Long]) extends Command {
   type T = Unit
@@ -37,5 +38,5 @@ case class BatchTagCommand(contentIds: List[String], toAddToTop: Option[Long], t
 }
 
 object BatchTagCommand {
-  implicit val batchTagCommandFormat = Jsonx.formatCaseClassUseDefaults[BatchTagCommand]
+  implicit val batchTagCommandFormat: OFormat[BatchTagCommand] = Jsonx.formatCaseClassUseDefaults[BatchTagCommand]
 }
diff --git a/app/model/command/CreateTagCommand.scala b/app/model/command/CreateTagCommand.scala
index f0b4dcd7..9e99325c 100644
--- a/app/model/command/CreateTagCommand.scala
+++ b/app/model/command/CreateTagCommand.scala
@@ -17,6 +17,7 @@ import play.api.Logging
 import services.KinesisStreams
 
 import scala.concurrent.{Future, ExecutionContext}
+import play.api.libs.json.OFormat
 
 case class InlinePaidContentSponsorshipCommand(
                          validFrom: Option[DateTime],
@@ -53,7 +54,7 @@ case class InlinePaidContentSponsorshipCommand(
 }
 
 object InlinePaidContentSponsorshipCommand {
-  implicit val inlinePaidContentSponsorshipFormat = Jsonx.formatCaseClassUseDefaults[InlinePaidContentSponsorshipCommand]
+  implicit val inlinePaidContentSponsorshipFormat: OFormat[InlinePaidContentSponsorshipCommand] = Jsonx.formatCaseClassUseDefaults[InlinePaidContentSponsorshipCommand]
 }
 
 case class CreateTagCommand(
@@ -207,5 +208,5 @@ case class CreateTagCommand(
 
 object CreateTagCommand {
 
-  implicit val createTagCommandFormat = Jsonx.formatCaseClassUseDefaults[CreateTagCommand]
+  implicit val createTagCommandFormat: OFormat[CreateTagCommand] = Jsonx.formatCaseClassUseDefaults[CreateTagCommand]
 }
diff --git a/app/model/forms/SpreadSheet.scala b/app/model/forms/SpreadSheet.scala
index 8df49842..e3d0bd09 100644
--- a/app/model/forms/SpreadSheet.scala
+++ b/app/model/forms/SpreadSheet.scala
@@ -34,6 +34,6 @@ object GetSpreadSheet {
     }
   }
 
-  implicit val filterFormat = Json.reads[SpreadSheetFilter]
-  implicit val format = Json.reads[GetSpreadSheet]
+  implicit val filterFormat: Reads[SpreadSheetFilter] = Json.reads[SpreadSheetFilter]
+  implicit val format: Reads[GetSpreadSheet] = Json.reads[GetSpreadSheet]
 }
diff --git a/app/model/image.scala b/app/model/image.scala
index 9db46090..18b3f582 100644
--- a/app/model/image.scala
+++ b/app/model/image.scala
@@ -19,7 +19,7 @@ case class Image(imageId: String, assets: List[ImageAsset]) {
 }
 
 object Image {
-  implicit val imageFormat = Jsonx.formatCaseClass[Image]
+  implicit val imageFormat: OFormat[Image] = Jsonx.formatCaseClass[Image]
 
   def apply(thriftImage: ThriftImage): Image = Image(
     imageId = thriftImage.imageId,
diff --git a/app/model/jobs/Step.scala b/app/model/jobs/Step.scala
index 13859061..2633bc38 100644
--- a/app/model/jobs/Step.scala
+++ b/app/model/jobs/Step.scala
@@ -172,7 +172,7 @@ object Step extends Logging {
     }
   }
 
-  implicit val stepFormat = Format(stepReads, stepWrites)
+  implicit val stepFormat: Format[Step] = Format(stepReads, stepWrites)
 }
 
 // Step status is required so we know which steps require rollback
diff --git a/app/modules/sponsorshiplifecycle/SponsorshipLifecycleModule.scala b/app/modules/sponsorshiplifecycle/SponsorshipLifecycleModule.scala
index 807f29ac..caed5f45 100644
--- a/app/modules/sponsorshiplifecycle/SponsorshipLifecycleModule.scala
+++ b/app/modules/sponsorshiplifecycle/SponsorshipLifecycleModule.scala
@@ -86,7 +86,7 @@ class SponsorshipLauncher(implicit ec: ExecutionContext) extends AbstractSchedul
 }
 
 class SponsorshipExpirer(implicit ec: ExecutionContext) extends AbstractScheduledService with Logging {
-  implicit val username = Some("Sponsorship expirer")
+  implicit val username: Some[String] = Some("Sponsorship expirer")
 
   override def runOneIteration(): Unit = try {