diff --git a/beacon_chain/rpc/eth2_json_rest_serialization.nim b/beacon_chain/rpc/eth2_json_rest_serialization.nim
index 88c2edbf9..ab307b537 100644
--- a/beacon_chain/rpc/eth2_json_rest_serialization.nim
+++ b/beacon_chain/rpc/eth2_json_rest_serialization.nim
@@ -151,6 +151,23 @@ proc readValue*(reader: var JsonReader[RestJson], value: var ValidatorIndex) {.
   else:
     reader.raiseUnexpectedValue($res.error())
 
+## RestValidatorIndex
+proc writeValue*(writer: var JsonWriter[RestJson],
+                 value: RestValidatorIndex) {.
+     raises: [IOError, Defect].} =
+  writeValue(writer, Base10.toString(uint64(value)))
+
+proc readValue*(reader: var JsonReader[RestJson],
+                value: var RestValidatorIndex) {.
+     raises: [IOError, SerializationError, Defect].} =
+  let svalue = reader.readValue(string)
+  let res = Base10.decode(uint64, svalue)
+  if res.isOk():
+    let v = res.get()
+    value = RestValidatorIndex(v)
+  else:
+    reader.raiseUnexpectedValue($res.error())
+
 ## CommitteeIndex
 proc writeValue*(writer: var JsonWriter[RestJson], value: CommitteeIndex) {.
      raises: [IOError, Defect].} =
diff --git a/beacon_chain/rpc/validator_rest_api.nim b/beacon_chain/rpc/validator_rest_api.nim
index 467454363..81883a489 100644
--- a/beacon_chain/rpc/validator_rest_api.nim
+++ b/beacon_chain/rpc/validator_rest_api.nim
@@ -48,11 +48,26 @@ proc installValidatorApiHandlers*(router: var RestRouter, node: BeaconNode) =
       block:
         if contentBody.isNone():
           return RestApiResponse.jsonError(Http400, "Empty request's body")
-        let dres = decodeBody(seq[ValidatorIndex], contentBody.get())
+        let dres = decodeBody(seq[RestValidatorIndex], contentBody.get())
         if dres.isErr():
           return RestApiResponse.jsonError(Http400, "Unable to decode " &
             "list of validator indexes", $dres.error())
-        dres.get()
+        var res: seq[ValidatorIndex]
+        let items = dres.get()
+        for item in items:
+          let vres = item.toValidatorIndex()
+          if vres.isErr():
+            case vres.error()
+            of ValidatorIndexError.TooHighValue:
+              return RestApiResponse.jsonError(Http400,
+                                              "Incorrect validator index value")
+            of ValidatorIndexError.UnsupportedValue:
+              return RestApiResponse.jsonError(Http500,
+                                            "Unsupported validator index value")
+          res.add(vres.get())
+        if len(res) == 0:
+          return RestApiResponse.jsonError(Http400, "Empty indexes list")
+        res
     let qepoch =
       block:
         if epoch.isErr():