diff --git a/dist/main_bun.mjs b/dist/main_bun.mjs
index ef6fa8a..094571c 100644
--- a/dist/main_bun.mjs
+++ b/dist/main_bun.mjs
@@ -84,7 +84,13 @@ function openAiMessageToGeminiMessage(messages) {
   return result;
 }
 function genModel(req) {
-  const model = ModelMapping[req.model] ?? "gemini-1.0-pro-latest";
+  const defaultModel = (m) => {
+    if (m.startsWith("gemini")) {
+      return m;
+    }
+    return "gemini-1.5-flash-latest";
+  };
+  const model = ModelMapping[req.model] ?? defaultModel(req.model);
   let functions = req.tools?.filter((it) => it.type === "function")?.map((it) => it.function) ?? [];
   functions = functions.concat(req.functions ?? []);
   const responseMimeType = req.response_format?.type === "json_object" ? "application/json" : "text/plain";
diff --git a/dist/main_cloudflare-workers.mjs b/dist/main_cloudflare-workers.mjs
index 1801114..e4b42e5 100644
--- a/dist/main_cloudflare-workers.mjs
+++ b/dist/main_cloudflare-workers.mjs
@@ -84,7 +84,13 @@ function openAiMessageToGeminiMessage(messages) {
   return result;
 }
 function genModel(req) {
-  const model = ModelMapping[req.model] ?? "gemini-1.0-pro-latest";
+  const defaultModel = (m) => {
+    if (m.startsWith("gemini")) {
+      return m;
+    }
+    return "gemini-1.5-flash-latest";
+  };
+  const model = ModelMapping[req.model] ?? defaultModel(req.model);
   let functions = req.tools?.filter((it) => it.type === "function")?.map((it) => it.function) ?? [];
   functions = functions.concat(req.functions ?? []);
   const responseMimeType = req.response_format?.type === "json_object" ? "application/json" : "text/plain";
diff --git a/dist/main_deno.mjs b/dist/main_deno.mjs
index 8b12c09..6387336 100644
--- a/dist/main_deno.mjs
+++ b/dist/main_deno.mjs
@@ -84,7 +84,13 @@ function openAiMessageToGeminiMessage(messages) {
   return result;
 }
 function genModel(req) {
-  const model = ModelMapping[req.model] ?? "gemini-1.0-pro-latest";
+  const defaultModel = (m) => {
+    if (m.startsWith("gemini")) {
+      return m;
+    }
+    return "gemini-1.5-flash-latest";
+  };
+  const model = ModelMapping[req.model] ?? defaultModel(req.model);
   let functions = req.tools?.filter((it) => it.type === "function")?.map((it) => it.function) ?? [];
   functions = functions.concat(req.functions ?? []);
   const responseMimeType = req.response_format?.type === "json_object" ? "application/json" : "text/plain";
diff --git a/dist/main_node.mjs b/dist/main_node.mjs
index e36e392..59f74e0 100644
--- a/dist/main_node.mjs
+++ b/dist/main_node.mjs
@@ -524,7 +524,13 @@ function openAiMessageToGeminiMessage(messages) {
   return result;
 }
 function genModel(req) {
-  const model = ModelMapping[req.model] ?? "gemini-1.0-pro-latest";
+  const defaultModel = (m) => {
+    if (m.startsWith("gemini")) {
+      return m;
+    }
+    return "gemini-1.5-flash-latest";
+  };
+  const model = ModelMapping[req.model] ?? defaultModel(req.model);
   let functions = req.tools?.filter((it) => it.type === "function")?.map((it) => it.function) ?? [];
   functions = functions.concat(req.functions ?? []);
   const responseMimeType = req.response_format?.type === "json_object" ? "application/json" : "text/plain";
diff --git a/src/utils.ts b/src/utils.ts
index 4c39d86..bbaf3f4 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -74,7 +74,14 @@ export function openAiMessageToGeminiMessage(messages: OpenAI.Chat.ChatCompletio
 }
 
 export function genModel(req: OpenAI.Chat.ChatCompletionCreateParams): [GeminiModel, GenerateContentRequest] {
-  const model: GeminiModel = ModelMapping[req.model] ?? "gemini-1.0-pro-latest"
+  const defaultModel = (m: string): GeminiModel => {
+    if (m.startsWith("gemini")) {
+      return m as GeminiModel
+    }
+    return "gemini-1.5-flash-latest"
+  }
+
+  const model: GeminiModel = ModelMapping[req.model] ?? defaultModel(req.model)
 
   let functions: OpenAI.Chat.FunctionObject[] =
     req.tools?.filter((it) => it.type === "function")?.map((it) => it.function) ?? []