diff --git a/AGENTS.md b/AGENTS.md
index ebbf146..5be9fc3 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -347,8 +347,8 @@ https://github.com/settings/apps/dalestudy
 ### 4. Worker Secrets 설정
 
 ```bash
-# OpenAI API Key (AI 코드 리뷰용, 필수)
-wrangler secret put OPENAI_API_KEY
+# AI Gateway 인증 토큰 (AI 코드 리뷰용, 필수)
+wrangler secret put AI_GATEWAY_TOKEN
 
 # Webhook Secret (선택사항)
 wrangler secret put WEBHOOK_SECRET
diff --git a/handlers/complexity-analysis.js b/handlers/complexity-analysis.js
index e30e3f8..d574d47 100644
--- a/handlers/complexity-analysis.js
+++ b/handlers/complexity-analysis.js
@@ -10,6 +10,8 @@
  *  - LLM : actualTime / actualSpace / feedback / suggestion / headerLine 만 책임.
  */
 
+import { aiGatewayHeaders, OPENAI_CHAT_COMPLETIONS_URL } from "../utils/constants.js";
+
 // ── 상수 ──────────────────────────────────────────
 
 const FILE_DELIMITER = "=====";
@@ -240,7 +242,7 @@ export function composeSolution(modelSol, originalContent) {
   };
 }
 
-export async function callComplexityAnalysis(fileEntries, apiKey) {
+export async function callComplexityAnalysis(fileEntries, gatewayToken) {
   const userPrompt = fileEntries
     .map(
       (f) =>
@@ -248,12 +250,9 @@ export async function callComplexityAnalysis(fileEntries, apiKey) {
     )
     .join("\n\n");
 
-  const response = await fetch("https://api.openai.com/v1/chat/completions", {
+  const response = await fetch(OPENAI_CHAT_COMPLETIONS_URL, {
     method: "POST",
-    headers: {
-      Authorization: `Bearer ${apiKey}`,
-      "Content-Type": "application/json",
-    },
+    headers: aiGatewayHeaders(gatewayToken),
     body: JSON.stringify({
       model: "gpt-5-nano",
       messages: [
diff --git a/handlers/complexity-analysis.test.js b/handlers/complexity-analysis.test.js
index 89088d7..cd5cf9f 100644
--- a/handlers/complexity-analysis.test.js
+++ b/handlers/complexity-analysis.test.js
@@ -557,6 +557,26 @@ function solution() { return 0; }`;
     expect(captured).not.toContain("TC: O(n)");
     expect(captured).not.toContain("SC: O(1)");
   });
+
+  it("AI Gateway 인증 헤더와 재시도 헤더를 함께 보낸다", async () => {
+    let captured = null;
+    globalThis.fetch = vi.fn().mockImplementation(async (url, opts) => {
+      captured = opts.headers;
+      return await makeOpenAIResponse([makeSingleSolutionAnalysis("two-sum")]);
+    });
+
+    await callComplexityAnalysis(
+      [{ problemName: "two-sum", content: PLAIN_SOURCE }],
+      "fake-key"
+    );
+
+    expect(captured).toMatchObject({
+      "cf-aig-authorization": "Bearer fake-key",
+      "cf-aig-max-attempts": "3",
+      "cf-aig-retry-delay": "1000",
+      "cf-aig-backoff": "exponential",
+    });
+  });
 });
 
 // ── renderComplexitySection ───────────────────────
diff --git a/handlers/internal-dispatch.js b/handlers/internal-dispatch.js
index f060b78..45e33fe 100644
--- a/handlers/internal-dispatch.js
+++ b/handlers/internal-dispatch.js
@@ -72,7 +72,7 @@ async function handleTagPatterns(payload, appToken, env) {
     headSha,
     prData,
     appToken,
-    env.OPENAI_API_KEY
+    env.AI_GATEWAY_TOKEN
   );
   return corsResponse({ handler: "tag-patterns", result });
 }
@@ -85,7 +85,7 @@ async function handleLearningStatus(payload, appToken, env) {
     prNumber,
     username,
     appToken,
-    env.OPENAI_API_KEY
+    env.AI_GATEWAY_TOKEN
   );
   return corsResponse({ handler: "learning-status", result });
 }
diff --git a/handlers/internal-dispatch.test.js b/handlers/internal-dispatch.test.js
index 6522889..0a335da 100644
--- a/handlers/internal-dispatch.test.js
+++ b/handlers/internal-dispatch.test.js
@@ -88,7 +88,7 @@ describe("handleInternalDispatch — 인증", () => {
 });
 
 describe("handleInternalDispatch — 라우팅", () => {
-  const env = { INTERNAL_SECRET: VALID_SECRET, OPENAI_API_KEY: "fake-openai" };
+  const env = { INTERNAL_SECRET: VALID_SECRET, AI_GATEWAY_TOKEN: "fake-gateway-token" };
 
   beforeEach(() => {
     vi.clearAllMocks();
@@ -123,7 +123,7 @@ describe("handleInternalDispatch — 라우팅", () => {
       "abc123",
       prData,
       "fake-token",
-      "fake-openai"
+      "fake-gateway-token"
     );
     expect(postLearningStatus).not.toHaveBeenCalled();
   });
@@ -154,7 +154,7 @@ describe("handleInternalDispatch — 라우팅", () => {
       42,
       "testuser",
       "fake-token",
-      "fake-openai"
+      "fake-gateway-token"
     );
     expect(tagPatterns).not.toHaveBeenCalled();
   });
@@ -200,7 +200,7 @@ describe("handleInternalDispatch — 라우팅", () => {
 });
 
 describe("handleInternalDispatch — 에러 처리", () => {
-  const env = { INTERNAL_SECRET: VALID_SECRET, OPENAI_API_KEY: "fake-openai" };
+  const env = { INTERNAL_SECRET: VALID_SECRET, AI_GATEWAY_TOKEN: "fake-gateway-token" };
 
   beforeEach(() => {
     vi.clearAllMocks();
diff --git a/handlers/webhooks.js b/handlers/webhooks.js
index 39058e9..153cb2a 100644
--- a/handlers/webhooks.js
+++ b/handlers/webhooks.js
@@ -260,7 +260,7 @@ async function handlePullRequestEvent(payload, env, ctx) {
   }
 
   // AI 핸들러들을 별도 Worker 호출로 디스패치 (각각 독립적인 subrequest 예산)
-  if (env.OPENAI_API_KEY && env.INTERNAL_SECRET && env.WORKER_URL) {
+  if (env.AI_GATEWAY_TOKEN && env.INTERNAL_SECRET && env.WORKER_URL) {
     const baseUrl = env.WORKER_URL;
 
     const dispatchHeaders = {
@@ -300,7 +300,7 @@ async function handlePullRequestEvent(payload, env, ctx) {
     );
 
     console.log(`[handlePullRequestEvent] Dispatched 2 AI handlers for PR #${prNumber}`);
-  } else if (env.OPENAI_API_KEY) {
+  } else if (env.AI_GATEWAY_TOKEN) {
     // INTERNAL_SECRET/WORKER_URL 미설정 시 기존 방식으로 폴백 (동일 invocation에서 순차 실행)
     console.warn("[handlePullRequestEvent] INTERNAL_SECRET or WORKER_URL not set, running handlers in-process");
 
@@ -312,14 +312,14 @@ async function handlePullRequestEvent(payload, env, ctx) {
         pr.head.sha,
         pr,
         appToken,
-        env.OPENAI_API_KEY
+        env.AI_GATEWAY_TOKEN
       );
     } catch (error) {
       console.error(`[handlePullRequestEvent] tagPatterns failed: ${error.message}`);
     }
 
     try {
-      await postLearningStatus(repoOwner, repoName, prNumber, pr.user.login, appToken, env.OPENAI_API_KEY);
+      await postLearningStatus(repoOwner, repoName, prNumber, pr.user.login, appToken, env.AI_GATEWAY_TOKEN);
     } catch (error) {
       console.error(`[handlePullRequestEvent] learningStatus failed: ${error.message}`);
     }
@@ -483,9 +483,9 @@ async function handleIssueCommentEvent(payload, env) {
   // AI 코드 리뷰 요청 처리
   console.log(`AI review requested for PR #${prNumber}${mention.userRequest ? ` - Request: ${mention.userRequest}` : ""}`);
 
-  // OPENAI_API_KEY 확인
-  if (!env.OPENAI_API_KEY) {
-    console.log("OPENAI_API_KEY not configured");
+  // AI_GATEWAY_TOKEN 확인
+  if (!env.AI_GATEWAY_TOKEN) {
+    console.log("AI_GATEWAY_TOKEN not configured");
     return corsResponse({ message: "AI review not configured" });
   }
 
@@ -508,7 +508,7 @@ async function handleIssueCommentEvent(payload, env) {
       issue.title,
       issue.body,
       appToken,
-      env.OPENAI_API_KEY,
+      env.AI_GATEWAY_TOKEN,
       mention.userRequest
     );
 
@@ -553,9 +553,9 @@ async function handlePullRequestReviewCommentEvent(payload, env) {
 
   console.log(`AI review requested for PR #${prNumber} (review comment)${mention.userRequest ? ` - Request: ${mention.userRequest}` : ""}`);
 
-  // OPENAI_API_KEY 확인
-  if (!env.OPENAI_API_KEY) {
-    console.log("OPENAI_API_KEY not configured");
+  // AI_GATEWAY_TOKEN 확인
+  if (!env.AI_GATEWAY_TOKEN) {
+    console.log("AI_GATEWAY_TOKEN not configured");
     return corsResponse({ message: "AI review not configured" });
   }
 
@@ -581,7 +581,7 @@ async function handlePullRequestReviewCommentEvent(payload, env) {
       pullRequest.title,
       pullRequest.body,
       appToken,
-      env.OPENAI_API_KEY,
+      env.AI_GATEWAY_TOKEN,
       mention.userRequest,
       comment.id  // 스레드 답변으로 작성
     );
diff --git a/handlers/webhooks.test.js b/handlers/webhooks.test.js
index 5598bf3..f862b14 100644
--- a/handlers/webhooks.test.js
+++ b/handlers/webhooks.test.js
@@ -264,10 +264,10 @@ describe("handlePullRequestEvent — AI 핸들러 디스패치", () => {
     });
   });
 
-  it("OPENAI_API_KEY, INTERNAL_SECRET, WORKER_URL 이 모두 설정되면 ctx.waitUntil 로 self-fetch 2 회를 디스패치한다", async () => {
+  it("AI_GATEWAY_TOKEN, INTERNAL_SECRET, WORKER_URL 이 모두 설정되면 ctx.waitUntil 로 self-fetch 2 회를 디스패치한다", async () => {
     const ctx = makeCtx();
     const env = {
-      OPENAI_API_KEY: "fake-openai",
+      AI_GATEWAY_TOKEN: "fake-gateway-token",
       INTERNAL_SECRET: "fake-secret",
       WORKER_URL: "https://worker.test",
     };
@@ -299,7 +299,7 @@ describe("handlePullRequestEvent — AI 핸들러 디스패치", () => {
   it("INTERNAL_SECRET 이 없으면 in-process 핸들러 호출로 폴백한다", async () => {
     const ctx = makeCtx();
     const env = {
-      OPENAI_API_KEY: "fake-openai",
+      AI_GATEWAY_TOKEN: "fake-gateway-token",
       WORKER_URL: "https://worker.test",
     };
 
@@ -323,7 +323,7 @@ describe("handlePullRequestEvent — AI 핸들러 디스패치", () => {
   it("WORKER_URL 이 없으면 in-process 핸들러 호출로 폴백한다", async () => {
     const ctx = makeCtx();
     const env = {
-      OPENAI_API_KEY: "fake-openai",
+      AI_GATEWAY_TOKEN: "fake-gateway-token",
       INTERNAL_SECRET: "fake-secret",
     };
 
@@ -339,7 +339,7 @@ describe("handlePullRequestEvent — AI 핸들러 디스패치", () => {
     expect(postLearningStatus).toHaveBeenCalledTimes(1);
   });
 
-  it("OPENAI_API_KEY 가 없으면 디스패치도 핸들러 호출도 하지 않는다", async () => {
+  it("AI_GATEWAY_TOKEN 가 없으면 디스패치도 핸들러 호출도 하지 않는다", async () => {
     const ctx = makeCtx();
     const env = {
       INTERNAL_SECRET: "fake-secret",
diff --git a/tests/subrequest-budget.test.js b/tests/subrequest-budget.test.js
index f923bbf..362d3c8 100644
--- a/tests/subrequest-budget.test.js
+++ b/tests/subrequest-budget.test.js
@@ -59,7 +59,7 @@ describe("subrequest 예산 — 핸들러별 invocation", () => {
         return okText("function solution() { return 0; }");
       }
 
-      if (urlStr.includes("openai.com/v1/chat/completions")) {
+      if (urlStr.includes("/openai/chat/completions")) {
         const body = JSON.parse(opts.body);
         const isComplexity = body.messages[0].content.includes(
           "시간/공간 복잡도를 분석"
@@ -225,7 +225,7 @@ describe("subrequest 예산 — 핸들러별 invocation", () => {
         return okText("function solution() { return 0; }");
       }
 
-      if (urlStr.includes("openai.com/v1/chat/completions")) {
+      if (urlStr.includes("/openai/chat/completions")) {
         return okJson({
           choices: [
             {
diff --git a/tests/tag-patterns.test.js b/tests/tag-patterns.test.js
index 759883d..1c8bd37 100644
--- a/tests/tag-patterns.test.js
+++ b/tests/tag-patterns.test.js
@@ -99,7 +99,7 @@ function makeFetchMock({
       return okText(rawContent);
     }
 
-    if (urlStr.includes("openai.com/v1/chat/completions")) {
+    if (urlStr.includes("/openai/chat/completions")) {
       const body = JSON.parse(opts.body);
       const isComplexity = body.messages[0].content.includes(
         "시간/공간 복잡도를 분석"
@@ -427,7 +427,7 @@ describe("tagPatterns — 레거시 단독 복잡도 issue comment 마이그레
       if (urlStr.startsWith("https://raw.example.com/")) {
         return okText(PLAIN_SOURCE);
       }
-      if (urlStr.includes("openai.com")) {
+      if (urlStr.includes("/openai/chat/completions")) {
         const body = JSON.parse(opts.body);
         const isComplexity = body.messages[0].content.includes(
           "시간/공간 복잡도를 분석"
@@ -495,7 +495,7 @@ describe("tagPatterns — 레거시 단독 복잡도 issue comment 마이그레
       if (urlStr.startsWith("https://raw.example.com/")) {
         return okText(PLAIN_SOURCE);
       }
-      if (urlStr.includes("openai.com")) {
+      if (urlStr.includes("/openai/chat/completions")) {
         const body = JSON.parse(opts.body);
         const isComplexity = body.messages[0].content.includes(
           "시간/공간 복잡도를 분석"
@@ -557,7 +557,7 @@ describe("tagPatterns — 레거시 단독 복잡도 issue comment 마이그레
       if (urlStr.startsWith("https://raw.example.com/")) {
         return okText(PLAIN_SOURCE);
       }
-      if (urlStr.includes("openai.com")) {
+      if (urlStr.includes("/openai/chat/completions")) {
         const body = JSON.parse(opts.body);
         const isComplexity = body.messages[0].content.includes(
           "시간/공간 복잡도를 분석"
diff --git a/utils/constants.js b/utils/constants.js
index 1e87a01..aca9752 100644
--- a/utils/constants.js
+++ b/utils/constants.js
@@ -15,3 +15,32 @@ export const ALLOWED_REPO = "leetcode-study";
 
 // 라벨
 export const MAINTENANCE_LABEL = "maintenance";
+
+// AI Gateway 를 거치는 OpenAI 엔드포인트.
+// OpenAI 키는 게이트웨이에 저장돼 있어 요청에 싣지 않는다. 키를 실으면
+// 게이트웨이가 저장된 키를 끼워 넣지 않고 그대로 전달한다.
+const AI_GATEWAY_ACCOUNT_ID = "86aa227176a624680f7d34e691472576";
+const AI_GATEWAY_ID = "dalestudy";
+export const OPENAI_CHAT_COMPLETIONS_URL = `https://gateway.ai.cloudflare.com/v1/${AI_GATEWAY_ACCOUNT_ID}/${AI_GATEWAY_ID}/openai/chat/completions`;
+
+// 게이트웨이에 재시도를 맡긴다. Worker 안에서 재시도하면 CPU 예산을 깎지만,
+// 엣지에서 재시도하면 응답을 기다리는 시간일 뿐이다.
+const AI_GATEWAY_RETRY_HEADERS = {
+  "cf-aig-max-attempts": "3",
+  "cf-aig-retry-delay": "1000",
+  "cf-aig-backoff": "exponential",
+};
+
+/**
+ * AI Gateway 경유 OpenAI 호출에 붙일 헤더.
+ *
+ * @param {string} gatewayToken - AI Gateway 인증 토큰
+ * @returns {Record<string, string>}
+ */
+export function aiGatewayHeaders(gatewayToken) {
+  return {
+    "cf-aig-authorization": `Bearer ${gatewayToken}`,
+    "Content-Type": "application/json",
+    ...AI_GATEWAY_RETRY_HEADERS,
+  };
+}
diff --git a/utils/openai.js b/utils/openai.js
index 99cda69..796d2ad 100644
--- a/utils/openai.js
+++ b/utils/openai.js
@@ -1,6 +1,7 @@
 /**
- * OpenAI API 통합 (GPT-4.1-nano)
+ * OpenAI API 통합 (AI Gateway 경유)
  */
+import { aiGatewayHeaders, OPENAI_CHAT_COMPLETIONS_URL } from "./constants.js";
 
 /**
  * PR diff를 분석하여 AI 코드 리뷰 생성
@@ -8,7 +9,7 @@
  * @param {string} prDiff - PR의 diff 내용
  * @param {string} prTitle - PR 제목
  * @param {string} prBody - PR 본문
- * @param {string} apiKey - OpenAI API 키
+ * @param {string} gatewayToken - AI Gateway 인증 토큰
  * @param {string} userRequest - 사용자의 구체적인 요청 (선택사항)
  * @returns {Promise<string>} AI가 생성한 리뷰 댓글 (마크다운)
  */
@@ -16,7 +17,7 @@ export async function generateCodeReview(
   prDiff,
   prTitle,
   prBody,
-  apiKey,
+  gatewayToken,
   userRequest = null
 ) {
   // userRequest가 있으면 Q&A 모드, 없으면 전체 리뷰 모드
@@ -62,12 +63,9 @@ ${prDiff}
     userPrompt += `\n이 풀 리퀘스트를 리뷰해주세요.`;
   }
 
-  const response = await fetch("https://api.openai.com/v1/chat/completions", {
+  const response = await fetch(OPENAI_CHAT_COMPLETIONS_URL, {
     method: "POST",
-    headers: {
-      Authorization: `Bearer ${apiKey}`,
-      "Content-Type": "application/json",
-    },
+    headers: aiGatewayHeaders(gatewayToken),
     body: JSON.stringify({
       model: "gpt-5-nano",
       messages: [
@@ -93,10 +91,10 @@ ${prDiff}
  *
  * @param {string} fileContent - 분석할 소스 코드 내용
  * @param {string} problemName - 문제 이름 (폴더명)
- * @param {string} apiKey - OpenAI API 키
+ * @param {string} gatewayToken - AI Gateway 인증 토큰
  * @returns {Promise<{patterns: string[], description: string}>}
  */
-export async function generatePatternAnalysis(fileContent, problemName, apiKey) {
+export async function generatePatternAnalysis(fileContent, problemName, gatewayToken) {
   const systemPrompt = `당신은 리트코드 문제 풀이의 알고리즘 패턴을 분석하는 전문가입니다.
 주어진 소스 코드를 분석해서, 다음 패턴 목록 중 해당되는 것만 골라주세요.
 
@@ -140,12 +138,9 @@ ${fileContent}
 
 위 코드에 사용된 알고리즘 패턴을 분석해주세요.`;
 
-  const response = await fetch("https://api.openai.com/v1/chat/completions", {
+  const response = await fetch(OPENAI_CHAT_COMPLETIONS_URL, {
     method: "POST",
-    headers: {
-      Authorization: `Bearer ${apiKey}`,
-      "Content-Type": "application/json",
-    },
+    headers: aiGatewayHeaders(gatewayToken),
     body: JSON.stringify({
       model: "gpt-5-nano",
       messages: [
@@ -184,10 +179,10 @@ ${fileContent}
  * @param {string} fileContent - 분석할 소스 코드 내용
  * @param {string} problemName - 문제 이름 (폴더명)
  * @param {{difficulty: string, categories: string[], intended_approach: string}} problemInfo - 문제 메타 정보
- * @param {string} apiKey - OpenAI API 키
+ * @param {string} gatewayToken - AI Gateway 인증 토큰
  * @returns {Promise<{matches: boolean, explanation: string}>}
  */
-export async function generateApproachAnalysis(fileContent, problemName, problemInfo, apiKey) {
+export async function generateApproachAnalysis(fileContent, problemName, problemInfo, gatewayToken) {
   const systemPrompt = `You are an algorithm analysis expert. Determine if code matches the intended approach.
 
 Respond with a JSON object in this exact format:
@@ -218,12 +213,9 @@ ${truncatedContent}
 
 위 코드가 의도된 접근법과 일치하는지 분석해주세요.`;
 
-  const response = await fetch("https://api.openai.com/v1/chat/completions", {
+  const response = await fetch(OPENAI_CHAT_COMPLETIONS_URL, {
     method: "POST",
-    headers: {
-      Authorization: `Bearer ${apiKey}`,
-      "Content-Type": "application/json",
-    },
+    headers: aiGatewayHeaders(gatewayToken),
     body: JSON.stringify({
       model: "gpt-5-nano",
       messages: [