diff --git a/go.mod b/go.mod
index 2a39c3d..2eab575 100644
--- a/go.mod
+++ b/go.mod
@@ -11,6 +11,7 @@ require (
 	github.com/jmoiron/sqlx v1.2.0
 	github.com/lestrrat-go/jwx v1.2.0 // indirect
 	github.com/ory/dockertest/v3 v3.6.2
+	github.com/patrickmn/go-cache v2.1.0+incompatible // indirect
 	github.com/prometheus/client_golang v1.10.0 // indirect
 	github.com/satori/go.uuid v1.2.0
 	goji.io v2.0.2+incompatible
diff --git a/go.sum b/go.sum
index 42a1dc3..af2ccc0 100644
--- a/go.sum
+++ b/go.sum
@@ -416,6 +416,8 @@ github.com/pact-foundation/pact-go v1.0.4 h1:OYkFijGHoZAYbOIb1LWXrwKQbMMRUv1oQ89
 github.com/pact-foundation/pact-go v1.0.4/go.mod h1:uExwJY4kCzNPcHRj+hCR/HBbOOIwwtUjcrb0b5/5kLM=
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c h1:Lgl0gzECD8GnQ5QCWA8o6BtfL6mDH5rQgM4/fX3avOs=
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
+github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pborman/uuid v1.2.0 h1:J7Q5mO4ysT1dv8hyrUGHb9+ooztCXu1D8MY8DZYsu3g=
 github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 github.com/performancecopilot/speed v3.0.0+incompatible h1:2WnRzIquHa5QxaJKShDkLM+sc0JPuwhXzK8OYOyt3Vg=
diff --git a/internal/config/config.go b/internal/config/config.go
index 17df61d..63a0f6a 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -16,9 +16,10 @@ type conf struct {
 	MySQLDSN        string
 	Port            int
 	ShoesPluginPath string
+	RunnerUser      string
 
-	RunnerUser string
-	Debug      bool
+	Debug  bool
+	Strict bool // check to registered runner before delete job
 }
 
 // Config Environment keys
@@ -30,4 +31,5 @@ const (
 	EnvPort                      = "PORT"
 	EnvShoesPluginPath           = "PLUGIN"
 	EnvDebug                     = "DEBUG"
+	EnvStrict                    = "STRICT"
 )
diff --git a/internal/config/init.go b/internal/config/init.go
index dab83c3..8964404 100644
--- a/internal/config/init.go
+++ b/internal/config/init.go
@@ -85,6 +85,11 @@ func Load() {
 	} else {
 		Config.Debug = false
 	}
+
+	Config.Strict = true
+	if os.Getenv(EnvStrict) == "false" {
+		Config.Strict = false
+	}
 }
 
 func checkBinary(p string) (string, error) {
diff --git a/pkg/gh/github.go b/pkg/gh/github.go
index 0fffa55..1da5733 100644
--- a/pkg/gh/github.go
+++ b/pkg/gh/github.go
@@ -8,6 +8,9 @@ import (
 	"net/url"
 	"path"
 	"strings"
+	"time"
+
+	"github.com/patrickmn/go-cache"
 
 	"github.com/bradleyfalzon/ghinstallation"
 	"github.com/google/go-github/v35/github"
@@ -19,8 +22,16 @@ import (
 var (
 	// ErrNotFound is error for not found
 	ErrNotFound = fmt.Errorf("not found")
+
+	// ResponseCache is cache variable
+	responseCache *cache.Cache
 )
 
+func init() {
+	c := cache.New(5*time.Minute, 10*time.Minute)
+	responseCache = c
+}
+
 // NewClient create a client of GitHub
 func NewClient(ctx context.Context, personalToken, gheDomain string) (*github.Client, error) {
 	ts := oauth2.StaticTokenSource(
@@ -96,13 +107,16 @@ func ExistGitHubRunner(ctx context.Context, client *github.Client, owner, repo,
 
 // ListRunners get runners that registered repository or org
 func ListRunners(ctx context.Context, client *github.Client, owner, repo string) ([]*github.Runner, error) {
-	var rs []*github.Runner
+	if cachedRs, found := responseCache.Get(getCacheKey(owner, repo)); found {
+		return cachedRs.([]*github.Runner), nil
+	}
 
 	var opts = &github.ListOptions{
 		Page:    0,
 		PerPage: 10,
 	}
 
+	var rs []*github.Runner
 	for {
 		logger.Logf(true, "get runners from GitHub, page: %d, now all runners: %d", opts.Page, len(rs))
 		runners, resp, err := listRunners(ctx, client, owner, repo, opts)
@@ -117,11 +131,16 @@ func ListRunners(ctx context.Context, client *github.Client, owner, repo string)
 		opts.Page = resp.NextPage
 	}
 
+	responseCache.Set(getCacheKey(owner, repo), rs, 1*time.Second)
 	logger.Logf(true, "found %d runners", len(rs))
 
 	return rs, nil
 }
 
+func getCacheKey(owner, repo string) string {
+	return fmt.Sprintf("owner-%s-repo-%s", owner, repo)
+}
+
 func listRunners(ctx context.Context, client *github.Client, owner, repo string, opts *github.ListOptions) (*github.Runners, *github.Response, error) {
 	if repo == "" {
 		runners, resp, err := client.Actions.ListOrganizationRunners(ctx, owner, opts)
diff --git a/pkg/starter/starter.go b/pkg/starter/starter.go
index 38a2d1a..bce3b8c 100644
--- a/pkg/starter/starter.go
+++ b/pkg/starter/starter.go
@@ -7,6 +7,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/whywaita/myshoes/internal/config"
+
 	uuid "github.com/satori/go.uuid"
 
 	"github.com/whywaita/myshoes/pkg/datastore"
@@ -107,20 +109,22 @@ func (s *Starter) do(ctx context.Context) error {
 				return
 			}
 
-			if err := s.checkRegisteredRunner(ctx, cloudID, *target); err != nil {
-				logger.Logf(false, "failed to check to register runner (target ID: %s, job ID: %s): %+v\n", job.TargetID, job.UUID, err)
+			if config.Config.Strict {
+				if err := s.checkRegisteredRunner(ctx, cloudID, *target); err != nil {
+					logger.Logf(false, "failed to check to register runner (target ID: %s, job ID: %s): %+v\n", job.TargetID, job.UUID, err)
 
-				if err := deleteInstance(ctx, cloudID); err != nil {
-					logger.Logf(false, "failed to delete an instance that not registered instance (target ID: %s, cloud ID: %s): %+v\n", job.TargetID, cloudID, err)
-					// not return, need to update target status if err.
-				}
+					if err := deleteInstance(ctx, cloudID); err != nil {
+						logger.Logf(false, "failed to delete an instance that not registered instance (target ID: %s, cloud ID: %s): %+v\n", job.TargetID, cloudID, err)
+						// not return, need to update target status if err.
+					}
+
+					if err := datastore.UpdateTargetStatus(ctx, s.ds, job.TargetID, datastore.TargetStatusErr, fmt.Sprintf("cannot register runner to GitHub (job ID: %s)", job.UUID)); err != nil {
+						logger.Logf(false, "failed to update target status (target ID: %s, job ID: %s): %+v\n", job.TargetID, job.UUID, err)
+						return
+					}
 
-				if err := datastore.UpdateTargetStatus(ctx, s.ds, job.TargetID, datastore.TargetStatusErr, fmt.Sprintf("cannot register runner to GitHub (job ID: %s)", job.UUID)); err != nil {
-					logger.Logf(false, "failed to update target status (target ID: %s, job ID: %s): %+v\n", job.TargetID, job.UUID, err)
 					return
 				}
-
-				return
 			}
 
 			r := datastore.Runner{
diff --git a/pkg/web/config.go b/pkg/web/config.go
index 634cd8f..72c0851 100644
--- a/pkg/web/config.go
+++ b/pkg/web/config.go
@@ -8,12 +8,16 @@ import (
 	"github.com/whywaita/myshoes/pkg/logger"
 )
 
-type inputConfig struct {
+type inputConfigDebug struct {
 	Debug bool `json:"debug"`
 }
 
+type inputConfigStrict struct {
+	Strict bool `json:"strict"`
+}
+
 func handleConfigDebug(w http.ResponseWriter, r *http.Request) {
-	i := inputConfig{}
+	i := inputConfigDebug{}
 
 	if err := json.NewDecoder(r.Body).Decode(&i); err != nil {
 		logger.Logf(false, "failed to decode request body: %+v", err)
@@ -26,3 +30,18 @@ func handleConfigDebug(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusNoContent)
 	return
 }
+
+func handleConfigStrict(w http.ResponseWriter, r *http.Request) {
+	i := inputConfigStrict{}
+
+	if err := json.NewDecoder(r.Body).Decode(&i); err != nil {
+		logger.Logf(false, "failed to decode request body: %+v", err)
+		outputErrorMsg(w, http.StatusBadRequest, "json decode error")
+		return
+	}
+
+	config.Config.Strict = i.Strict
+	logger.Logf(false, "switch strict mode to %t", i.Strict)
+	w.WriteHeader(http.StatusNoContent)
+	return
+}
diff --git a/pkg/web/http.go b/pkg/web/http.go
index 726cebb..c32699e 100644
--- a/pkg/web/http.go
+++ b/pkg/web/http.go
@@ -68,6 +68,10 @@ func NewMux(ds datastore.Datastore) *goji.Mux {
 		apacheLogging(r)
 		handleConfigDebug(w, r)
 	})
+	mux.HandleFunc(pat.Post("/config/strict"), func(w http.ResponseWriter, r *http.Request) {
+		apacheLogging(r)
+		handleConfigStrict(w, r)
+	})
 
 	return mux
 }