diff --git a/cl/beacon/builder/client.go b/cl/beacon/builder/client.go
index 62bb008dbb1..b34fe5d546f 100644
--- a/cl/beacon/builder/client.go
+++ b/cl/beacon/builder/client.go
@@ -26,7 +26,7 @@ func NewBlockBuilderClient(baseUrl string) *BlockBuilderClient {
 	}
 }
 
-func (b *BlockBuilderClient) RegisterValidator(ctx context.Context, registers []*ValidatorRegistration) error {
+func (b *BlockBuilderClient) RegisterValidator(ctx context.Context, registers []*cltypes.ValidatorRegistration) error {
 	// https://ethereum.github.io/builder-specs/#/Builder/registerValidator
 	url := b.baseUrl + "/eth/v1/builder/validators"
 	payload, err := json.Marshal(registers)
diff --git a/cl/beacon/builder/types.go b/cl/beacon/builder/types.go
index c5573e72fe5..60917660b85 100644
--- a/cl/beacon/builder/types.go
+++ b/cl/beacon/builder/types.go
@@ -12,16 +12,6 @@ type ExecutionPayloadHeader struct {
 	} `json:"data"`
 }
 
-type ValidatorRegistration struct {
-	Message struct {
-		FeeRecipient string `json:"fee_recipient"`
-		GasLimit     string `json:"gas_limit"`
-		Timestamp    string `json:"timestamp"`
-		PubKey       string `json:"pubkey"`
-	} `json:"message"`
-	Sginature string `json:"signature"`
-}
-
 type BlindedBlockResponse struct {
 	Version string            `json:"version"`
 	Data    cltypes.Eth1Block `json:"data"`
diff --git a/cl/beacon/handler/builder.go b/cl/beacon/handler/builder.go
index 006678528af..a8dcd3223d0 100644
--- a/cl/beacon/handler/builder.go
+++ b/cl/beacon/handler/builder.go
@@ -1,12 +1,14 @@
 package handler
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
 
 	libcommon "github.com/ledgerwatch/erigon-lib/common"
 	"github.com/ledgerwatch/erigon/cl/beacon/beaconhttp"
 	"github.com/ledgerwatch/erigon/cl/clparams"
+	"github.com/ledgerwatch/erigon/cl/cltypes"
 	"github.com/ledgerwatch/erigon/cl/persistence/beacon_indicies"
 	"github.com/ledgerwatch/erigon/cl/phase1/core/state"
 )
@@ -70,3 +72,20 @@ func (a *ApiHandler) GetEth1V1BuilderStatesExpectedWithdrawals(w http.ResponseWr
 
 	return nil, beaconhttp.NewEndpointError(http.StatusNotFound, fmt.Errorf("state not found"))
 }
+
+func (a *ApiHandler) PostEthV1BuilderRegisterValidator(w http.ResponseWriter, r *http.Request) (*beaconhttp.BeaconResponse, error) {
+	registerReq := []*cltypes.ValidatorRegistration{}
+	if err := json.NewDecoder(r.Body).Decode(&registerReq); err != nil {
+		return nil, beaconhttp.NewEndpointError(http.StatusBadRequest, err)
+	}
+	if len(registerReq) == 0 {
+		return nil, beaconhttp.NewEndpointError(http.StatusBadRequest, fmt.Errorf("empty request"))
+	}
+	if err := a.builderClient.RegisterValidator(r.Context(), registerReq); err != nil {
+		return nil, beaconhttp.NewEndpointError(http.StatusInternalServerError, err)
+	}
+	for _, v := range registerReq {
+		a.logger.Debug("[Caplin] Registred new validator", "fee_recipient", v.Message.FeeRecipient)
+	}
+	return newBeaconResponse(nil), nil
+}
diff --git a/cl/beacon/handler/handler.go b/cl/beacon/handler/handler.go
index 846b9521bad..10e06f0be16 100644
--- a/cl/beacon/handler/handler.go
+++ b/cl/beacon/handler/handler.go
@@ -12,6 +12,7 @@ import (
 	"github.com/ledgerwatch/erigon/cl/beacon/beacon_router_configuration"
 	"github.com/ledgerwatch/erigon/cl/beacon/beaconevents"
 	"github.com/ledgerwatch/erigon/cl/beacon/beaconhttp"
+	"github.com/ledgerwatch/erigon/cl/beacon/builder"
 	"github.com/ledgerwatch/erigon/cl/beacon/synced_data"
 	"github.com/ledgerwatch/erigon/cl/clparams"
 	"github.com/ledgerwatch/erigon/cl/cltypes"
@@ -86,6 +87,7 @@ type ApiHandler struct {
 	voluntaryExitService             services.VoluntaryExitService
 	blsToExecutionChangeService      services.BLSToExecutionChangeService
 	proposerSlashingService          services.ProposerSlashingService
+	builderClient                    *builder.BlockBuilderClient
 }
 
 func NewApiHandler(
@@ -118,6 +120,7 @@ func NewApiHandler(
 	voluntaryExitService services.VoluntaryExitService,
 	blsToExecutionChangeService services.BLSToExecutionChangeService,
 	proposerSlashingService services.ProposerSlashingService,
+	builderClient *builder.BlockBuilderClient,
 ) *ApiHandler {
 	blobBundles, err := lru.New[common.Bytes48, BlobBundle]("blobs", maxBlobBundleCacheSize)
 	if err != nil {
@@ -158,6 +161,7 @@ func NewApiHandler(
 		voluntaryExitService:             voluntaryExitService,
 		blsToExecutionChangeService:      blsToExecutionChangeService,
 		proposerSlashingService:          proposerSlashingService,
+		builderClient:                    builderClient,
 	}
 }
 
@@ -182,6 +186,7 @@ func (a *ApiHandler) init() {
 		r.Route("/v1", func(r chi.Router) {
 			if a.routerCfg.Builder {
 				r.Get("/builder/states/{state_id}/expected_withdrawals", beaconhttp.HandleEndpointFunc(a.GetEth1V1BuilderStatesExpectedWithdrawals))
+				r.Post("/validator/register_validator", beaconhttp.HandleEndpointFunc(a.PostEthV1BuilderRegisterValidator))
 			}
 			if a.routerCfg.Events {
 				r.Get("/events", a.EventSourceGetV1Events)
diff --git a/cl/cltypes/builder.go b/cl/cltypes/builder.go
new file mode 100644
index 00000000000..57ec41840c5
--- /dev/null
+++ b/cl/cltypes/builder.go
@@ -0,0 +1,13 @@
+package cltypes
+
+import libcommon "github.com/ledgerwatch/erigon-lib/common"
+
+type ValidatorRegistration struct {
+	Message struct {
+		FeeRecipient libcommon.Address `json:"fee_recipient"`
+		GasLimit     string            `json:"gas_limit"`
+		Timestamp    string            `json:"timestamp"`
+		PubKey       libcommon.Bytes48 `json:"pubkey"`
+	} `json:"message"`
+	Signature libcommon.Bytes96 `json:"signature"`
+}
diff --git a/cmd/caplin/caplin1/run.go b/cmd/caplin/caplin1/run.go
index 22cc2266fec..969be1f2a52 100644
--- a/cmd/caplin/caplin1/run.go
+++ b/cmd/caplin/caplin1/run.go
@@ -297,6 +297,7 @@ func RunCaplinPhase1(ctx context.Context, engine execution_client.ExecutionEngin
 			voluntaryExitService,
 			blsToExecutionChangeService,
 			proposerSlashingService,
+			option.builderClient,
 		)
 		go beacon.ListenAndServe(&beacon.LayeredBeaconHandler{
 			ArchiveApi: apiHandler,