diff --git a/auth.go b/auth.go
index bd76dad..48f4f35 100644
--- a/auth.go
+++ b/auth.go
@@ -12,8 +12,8 @@ const getIAMUrl = "https://iam.api.cloud.yandex.net/iam/v1/tokens"
 // Always call it before creating a request.
 //
 // If you will use it when API key is specified, method CreateRequest(...) will always use API key.
-func (c *YandexGPTClient) UpdateIAMToken(ctx context.Context) error {
-	iamRq := YandexIAMRequest{APIKey: c.config.ApiKey}
+func (c *YandexGPTClient) GetIAMToken(ctx context.Context) error {
+	iamRq := YandexIAMRequest{OAuthToken: c.config.OAuthToken}
 	req, err := c.newRequest(ctx, http.MethodPost, getIAMUrl, iamRq)
 	if err != nil {
 		return err
@@ -26,6 +26,6 @@ func (c *YandexGPTClient) UpdateIAMToken(ctx context.Context) error {
 	}
 
 	//set new IAMToken
-	c.config.updateIAMToken(resp.IAMToken)
+	c.config.SetIAMToken(resp.IAMToken)
 	return nil
 }
diff --git a/client.go b/client.go
index ba418f0..d39ae00 100644
--- a/client.go
+++ b/client.go
@@ -53,6 +53,17 @@ func NewYandexGPTClientWithAPIKey(
 	}
 }
 
+func NewYandexGPTClientWithOAuthToken(
+	oauthToken string,
+) *YandexGPTClient {
+	config := NewYandexGPTClientConfigWithOAuthToken(oauthToken)
+
+	return &YandexGPTClient{
+		config:         config,
+		requestBuilder: internal.NewRequestBuilder(),
+	}
+}
+
 func (c *YandexGPTClient) newRequest(
 	ctx context.Context,
 	method,
@@ -100,6 +111,12 @@ func (c *YandexGPTClient) setHeaders(request *http.Request) {
 			fmt.Sprintf("Bearer %s", c.config.IAMToken),
 		)
 	}
+	if c.config.ApiKey != "" {
+		request.Header.Set(
+			"Authorization",
+			fmt.Sprintf("Bearer %s", c.config.ApiKey),
+		)
+	}
 }
 
 func (c *YandexGPTClient) handleResponseError(response *http.Response) error {
diff --git a/config.go b/config.go
index b542309..3f47417 100644
--- a/config.go
+++ b/config.go
@@ -3,6 +3,7 @@ package yandexgpt
 import "net/http"
 
 type YandexGPTClientConfig struct {
+	OAuthToken string
 	ApiKey     string
 	IAMToken   string
 	HTTPClient *http.Client
@@ -32,6 +33,15 @@ func NewYandexGPTClientConfigWithAPIKey(
 	}
 }
 
-func (c *YandexGPTClientConfig) updateIAMToken(iamToken string) {
+func NewYandexGPTClientConfigWithOAuthToken(
+	oauthToken string,
+) *YandexGPTClientConfig {
+	return &YandexGPTClientConfig{
+		OAuthToken: oauthToken,
+		HTTPClient: &http.Client{},
+	}
+}
+
+func (c *YandexGPTClientConfig) SetIAMToken(iamToken string) {
 	c.IAMToken = iamToken
 }
diff --git a/examples/completion/main.go b/examples/completion/main.go
index 7b6ff0b..4df2012 100644
--- a/examples/completion/main.go
+++ b/examples/completion/main.go
@@ -8,11 +8,11 @@ import (
 )
 
 func main() {
-	client := yandexgpt.NewYandexGPTClientWithAPIKey("API_KEY")
+	client := yandexgpt.NewYandexGPTClientWithOAuthToken("OAUTH_TOKEN")
 
 	// get, update and set iam token
 	ctx := context.Background()
-	err := client.UpdateIAMToken(ctx)
+	err := client.GetIAMToken(ctx)
 	if err != nil {
 		panic(err)
 	}
diff --git a/examples/completionAsync/main.go b/examples/completionAsync/main.go
index 43f1a51..ac2c392 100644
--- a/examples/completionAsync/main.go
+++ b/examples/completionAsync/main.go
@@ -10,11 +10,11 @@ import (
 )
 
 func main() {
-	client := yandexgpt.NewYandexGPTClientWithAPIKey("API_KEY")
+	client := yandexgpt.NewYandexGPTClientWithOAuthToken("OAUTH_TOKEN")
 
 	// get, update and set iam token
 	ctx := context.Background()
-	err := client.UpdateIAMToken(ctx)
+	err := client.GetIAMToken(ctx)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/request.go b/request.go
index b4dd2de..bc53d1e 100644
--- a/request.go
+++ b/request.go
@@ -13,5 +13,5 @@ type YandexGPTCompletionOptions struct {
 }
 
 type YandexIAMRequest struct {
-	APIKey string `json:"yandexPassportOauthToken"`
+	OAuthToken string `json:"yandexPassportOauthToken"`
 }