diff --git a/internal/quaiapi/backend.go b/internal/quaiapi/backend.go
index 7b926e20f2..06ba4cdf9a 100644
--- a/internal/quaiapi/backend.go
+++ b/internal/quaiapi/backend.go
@@ -106,6 +106,7 @@ type Backend interface {
 	SetDomInterface(domInterface core.CoreBackend)
 	BroadcastWorkShare(workShare *types.WorkObjectShareView, location common.Location) error
 	GetMaxTxInWorkShare() uint64
+	GetExpansionNumber() uint8
 
 	BadHashExistsInChain() bool
 	IsBlockHashABadHash(hash common.Hash) bool
diff --git a/internal/quaiapi/quai_api.go b/internal/quaiapi/quai_api.go
index ca351cbeb8..f30e04d2fb 100644
--- a/internal/quaiapi/quai_api.go
+++ b/internal/quaiapi/quai_api.go
@@ -856,9 +856,8 @@ func (s *PublicBlockChainQuaiAPI) ListRunningChains() []common.Location {
 	return s.b.GetSlicesRunning()
 }
 
-func (s *PublicBlockChainQuaiAPI) GetProtocolExpansionNumber() int {
-	// TODO: Implement this
-	return 0
+func (s *PublicBlockChainQuaiAPI) GetProtocolExpansionNumber() hexutil.Uint {
+	return hexutil.Uint(s.b.GetExpansionNumber())
 }
 
 // Calculate the amount of Quai that Qi can be converted to. Expect the current Header and the Qi amount in "qits", returns the quai amount in "its"
diff --git a/quai/api_backend.go b/quai/api_backend.go
index e95aedf21b..842f04df80 100644
--- a/quai/api_backend.go
+++ b/quai/api_backend.go
@@ -530,6 +530,10 @@ func (b *QuaiAPIBackend) SetCurrentExpansionNumber(expansionNumber uint8) {
 	b.quai.core.SetCurrentExpansionNumber(expansionNumber)
 }
 
+func (b *QuaiAPIBackend) GetExpansionNumber() uint8 {
+	return b.quai.core.GetExpansionNumber()
+}
+
 func (b *QuaiAPIBackend) WriteGenesisBlock(block *types.WorkObject, location common.Location) {
 	b.quai.core.WriteGenesisBlock(block, location)
 }