diff --git a/go.sum b/go.sum
index b0b409f..3141573 100644
--- a/go.sum
+++ b/go.sum
@@ -120,6 +120,7 @@ github.com/ethereum/go-ethereum v1.9.21 h1:8qRlhzrItnmUGdVlBzZLI2Tb46S0RdSNjFwIC
 github.com/ethereum/go-ethereum v1.9.21/go.mod h1:RXAVzbGrSGmDkDnHymruTAIEjUR3E4TX0EOpaj702sI=
 github.com/ethereum/go-ethereum v1.9.22 h1:/Fea9n2EWJuNJ9oahMq9luqjRBcbW7QWdThbcJl13ek=
 github.com/ethereum/go-ethereum v1.9.22/go.mod h1:FQjK3ZwD8C5DYn7ukTmFee36rq1dOMESiUfXr5RUc1w=
+github.com/ethereum/go-ethereum v1.9.23 h1:SIKhg/z4Q7AbvqcxuPYvMxf36che/Rq/Pp0IdYEkbtw=
 github.com/ethereum/go-ethereum v1.9.23/go.mod h1:JIfVb6esrqALTExdz9hRYvrP0xBDf6wCncIu1hNwHpM=
 github.com/fatih/color v1.3.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/color v1.9.0 h1:8xPHl4/q1VyqGIPif1F+1V3Y3lSmrq01EabUW3CoW5s=
diff --git a/services/mempool_service.go b/services/mempool_service.go
index 3e4498a..11765b1 100644
--- a/services/mempool_service.go
+++ b/services/mempool_service.go
@@ -17,18 +17,25 @@ package services
 import (
 	"context"
 
+	"github.com/coinbase/rosetta-bitcoin/configuration"
+
 	"github.com/coinbase/rosetta-sdk-go/server"
 	"github.com/coinbase/rosetta-sdk-go/types"
 )
 
 // MempoolAPIService implements the server.MempoolAPIServicer interface.
 type MempoolAPIService struct {
+	config *configuration.Configuration
 	client Client
 }
 
 // NewMempoolAPIService creates a new instance of a MempoolAPIService.
-func NewMempoolAPIService(client Client) server.MempoolAPIServicer {
+func NewMempoolAPIService(
+	config *configuration.Configuration,
+	client Client,
+) server.MempoolAPIServicer {
 	return &MempoolAPIService{
+		config: config,
 		client: client,
 	}
 }
@@ -38,6 +45,10 @@ func (s *MempoolAPIService) Mempool(
 	ctx context.Context,
 	request *types.NetworkRequest,
 ) (*types.MempoolResponse, *types.Error) {
+	if s.config.Mode != configuration.Online {
+		return nil, wrapErr(ErrUnavailableOffline, nil)
+	}
+
 	mempoolTransactions, err := s.client.RawMempool(ctx)
 	if err != nil {
 		return nil, wrapErr(ErrBitcoind, err)
@@ -58,5 +69,9 @@ func (s *MempoolAPIService) MempoolTransaction(
 	ctx context.Context,
 	request *types.MempoolTransactionRequest,
 ) (*types.MempoolTransactionResponse, *types.Error) {
+	if s.config.Mode != configuration.Online {
+		return nil, wrapErr(ErrUnavailableOffline, nil)
+	}
+
 	return nil, wrapErr(ErrUnimplemented, nil)
 }
diff --git a/services/mempool_service_test.go b/services/mempool_service_test.go
index 0484120..1e28154 100644
--- a/services/mempool_service_test.go
+++ b/services/mempool_service_test.go
@@ -18,15 +18,39 @@ import (
 	"context"
 	"testing"
 
+	"github.com/coinbase/rosetta-bitcoin/configuration"
 	mocks "github.com/coinbase/rosetta-bitcoin/mocks/services"
 
 	"github.com/coinbase/rosetta-sdk-go/types"
 	"github.com/stretchr/testify/assert"
 )
 
-func TestMempoolEndpoints(t *testing.T) {
+func TestMempoolEndpoints_Offline(t *testing.T) {
+	cfg := &configuration.Configuration{
+		Mode: configuration.Offline,
+	}
 	mockClient := &mocks.Client{}
-	servicer := NewMempoolAPIService(mockClient)
+	servicer := NewMempoolAPIService(cfg, mockClient)
+	ctx := context.Background()
+	mem, err := servicer.Mempool(ctx, nil)
+	assert.Nil(t, mem)
+	assert.Equal(t, ErrUnavailableOffline.Code, err.Code)
+	assert.Equal(t, ErrUnavailableOffline.Message, err.Message)
+
+	memTransaction, err := servicer.MempoolTransaction(ctx, nil)
+	assert.Nil(t, memTransaction)
+	assert.Equal(t, ErrUnavailableOffline.Code, err.Code)
+	assert.Equal(t, ErrUnavailableOffline.Message, err.Message)
+	mockClient.AssertExpectations(t)
+}
+
+func TestMempoolEndpoints_Online(t *testing.T) {
+	cfg := &configuration.Configuration{
+		Mode: configuration.Online,
+	}
+
+	mockClient := &mocks.Client{}
+	servicer := NewMempoolAPIService(cfg, mockClient)
 	ctx := context.Background()
 
 	mockClient.On("RawMempool", ctx).Return([]string{
diff --git a/services/router.go b/services/router.go
index 423389d..624d2e5 100644
--- a/services/router.go
+++ b/services/router.go
@@ -55,7 +55,7 @@ func NewBlockchainRouter(
 		asserter,
 	)
 
-	mempoolAPIService := NewMempoolAPIService(client)
+	mempoolAPIService := NewMempoolAPIService(config, client)
 	mempoolAPIController := server.NewMempoolAPIController(
 		mempoolAPIService,
 		asserter,