diff --git a/cloudflare/env.go b/cloudflare/env.go
index 75c09e6..85a28dd 100644
--- a/cloudflare/env.go
+++ b/cloudflare/env.go
@@ -2,11 +2,13 @@ package cloudflare
 
 import (
 	"context"
+
+	"github.com/syumai/workers/cloudflare/internal/cfruntimecontext"
 )
 
 // Getenv gets a value of an environment variable.
 //   - https://developers.cloudflare.com/workers/platform/environment-variables/
 //   - This function panics when a runtime context is not found.
 func Getenv(ctx context.Context, name string) string {
-	return getRuntimeContextEnv(ctx).Get(name).String()
+	return cfruntimecontext.GetRuntimeContextEnv(ctx).Get(name).String()
 }
diff --git a/cloudflare/runtimecontext.go b/cloudflare/internal/cfruntimecontext/cfruntimecontext.go
similarity index 79%
rename from cloudflare/runtimecontext.go
rename to cloudflare/internal/cfruntimecontext/cfruntimecontext.go
index bc3fd2d..cbc2228 100644
--- a/cloudflare/runtimecontext.go
+++ b/cloudflare/internal/cfruntimecontext/cfruntimecontext.go
@@ -1,4 +1,4 @@
-package cloudflare
+package cfruntimecontext
 
 import (
 	"context"
@@ -19,17 +19,17 @@ import (
  * - see: https://github.com/cloudflare/workers-types/blob/c8d9533caa4415c2156d2cf1daca75289d01ae70/index.d.ts#LL564
  */
 
-// getRuntimeContextEnv gets object which holds environment variables bound to Cloudflare worker.
+// GetRuntimeContextEnv gets object which holds environment variables bound to Cloudflare worker.
 // - see: https://github.com/cloudflare/workers-types/blob/c8d9533caa4415c2156d2cf1daca75289d01ae70/index.d.ts#L566
-func getRuntimeContextEnv(ctx context.Context) js.Value {
+func GetRuntimeContextEnv(ctx context.Context) js.Value {
 	runtimeCtxValue := runtimecontext.MustExtract(ctx)
 	return runtimeCtxValue.Get("env")
 }
 
-// getExecutionContext gets ExecutionContext object from context.
+// GetExecutionContext gets ExecutionContext object from context.
 // - see: https://github.com/cloudflare/workers-types/blob/c8d9533caa4415c2156d2cf1daca75289d01ae70/index.d.ts#L567
 // - see also: https://github.com/cloudflare/workers-types/blob/c8d9533caa4415c2156d2cf1daca75289d01ae70/index.d.ts#L554
-func getExecutionContext(ctx context.Context) js.Value {
+func GetExecutionContext(ctx context.Context) js.Value {
 	runtimeCtxValue := runtimecontext.MustExtract(ctx)
 	return runtimeCtxValue.Get("ctx")
 }
diff --git a/cloudflare/kv.go b/cloudflare/kv.go
index 13da052..fd1e935 100644
--- a/cloudflare/kv.go
+++ b/cloudflare/kv.go
@@ -6,6 +6,8 @@ import (
 	"io"
 	"syscall/js"
 
+	"github.com/syumai/workers/cloudflare/internal/cfruntimecontext"
+
 	"github.com/syumai/workers/internal/jsutil"
 )
 
@@ -21,7 +23,7 @@ type KVNamespace struct {
 //   - if the given variable name doesn't exist on runtime context, returns error.
 //   - This function panics when a runtime context is not found.
 func NewKVNamespace(ctx context.Context, varName string) (*KVNamespace, error) {
-	inst := getRuntimeContextEnv(ctx).Get(varName)
+	inst := cfruntimecontext.GetRuntimeContextEnv(ctx).Get(varName)
 	if inst.IsUndefined() {
 		return nil, fmt.Errorf("%s is undefined", varName)
 	}
diff --git a/cloudflare/r2bucket.go b/cloudflare/r2bucket.go
index 3697d04..e1d1add 100644
--- a/cloudflare/r2bucket.go
+++ b/cloudflare/r2bucket.go
@@ -6,6 +6,7 @@ import (
 	"io"
 	"syscall/js"
 
+	"github.com/syumai/workers/cloudflare/internal/cfruntimecontext"
 	"github.com/syumai/workers/internal/jsutil"
 )
 
@@ -22,7 +23,7 @@ type R2Bucket struct {
 //   - if the given variable name doesn't exist on runtime context, returns error.
 //   - This function panics when a runtime context is not found.
 func NewR2Bucket(ctx context.Context, varName string) (*R2Bucket, error) {
-	inst := getRuntimeContextEnv(ctx).Get(varName)
+	inst := cfruntimecontext.GetRuntimeContextEnv(ctx).Get(varName)
 	if inst.IsUndefined() {
 		return nil, fmt.Errorf("%s is undefined", varName)
 	}