diff --git a/.github/memberMap.json b/.github/memberMap.json
new file mode 100644
index 00000000..dc451241
--- /dev/null
+++ b/.github/memberMap.json
@@ -0,0 +1,22 @@
+{
+  "seong-jin-jo": {
+    "name": "조성진",
+    "slackId": "U07V0TY7CF9"
+  },
+  "dongjooyun": {
+    "name": "윤동주",
+    "slackId": "U09KJ5DTD2B"
+  },
+  "Hyeonjun0527": {
+    "name": "최현준",
+    "slackId": "U08298MKCBE"
+  },
+  "HA-SEUNG-JEONG": {
+    "name": "정하승",
+    "slackId": "U0A6HD2AB0E"
+  },
+  "solvedacuser": {
+    "name": "노정환",
+    "slackId": "U0A6NRTGK2Q"
+  }
+}
\ No newline at end of file
diff --git a/.github/workflows/notify-pr-author-on-review.yml b/.github/workflows/notify-pr-author-on-review.yml
index 9f60a07c..2946c441 100644
--- a/.github/workflows/notify-pr-author-on-review.yml
+++ b/.github/workflows/notify-pr-author-on-review.yml
@@ -9,10 +9,11 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
       - name: Extract Slack IDs and DM Text
         id: extract_info
-        env:
-          MEMBER_INFO: ${{ secrets.MEMBER_INFO_MAP }}
         run: |
           PR_AUTHOR="${{ github.event.pull_request.user.login }}"
           REVIEWER="${{ github.event.review.user.login }}"
@@ -26,10 +27,11 @@ jobs:
             exit 0
           fi
 
-          echo "$MEMBER_INFO" | base64 --decode > memberMap.json
-          AUTHOR_SLACK_ID=$(jq -r --arg id "$PR_AUTHOR" '.[$id].slackId' memberMap.json)
-          REVIEWER_SLACK_ID=$(jq -r --arg id "$REVIEWER" '.[$id].slackId' memberMap.json)
+          # 코드베이스의 memberMap.json에서 Slack ID 조회
+          AUTHOR_SLACK_ID=$(jq -r --arg id "$PR_AUTHOR" '.[$id].slackId // empty' .github/memberMap.json)
+          REVIEWER_SLACK_ID=$(jq -r --arg id "$REVIEWER" '.[$id].slackId // empty' .github/memberMap.json)
 
+          # slackId가 없으면 DM 전송 불가 (skip)
           if [ -z "$AUTHOR_SLACK_ID" ] || [ -z "$REVIEWER_SLACK_ID" ] || \
             [ "$AUTHOR_SLACK_ID" = "null" ] || [ "$REVIEWER_SLACK_ID" = "null" ]; then
             echo "skip=true" >> $GITHUB_OUTPUT
diff --git a/.github/workflows/notify-slack-on-pr-opened.yml b/.github/workflows/notify-slack-on-pr-opened.yml
index 9a67acf0..0d1f67a2 100644
--- a/.github/workflows/notify-slack-on-pr-opened.yml
+++ b/.github/workflows/notify-slack-on-pr-opened.yml
@@ -13,19 +13,29 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Decode memberMap.json from secret
-        run: |
-          echo "${{ secrets.MEMBER_INFO_MAP }}" | base64 --decode > memberMap.json
+      - name: Checkout
+        uses: actions/checkout@v4
+
       - name: Get PR author and reviewers
         id: get_member_info
         run: |
           # PR 작성자 이름 추출
           PR_AUTHOR_GITHUB_ID="${{ github.event.pull_request.user.login }}"
-          PR_AUTHOR_NAME=$(jq -r --arg id "$PR_AUTHOR_GITHUB_ID" '.[$id].name' memberMap.json)
+          PR_AUTHOR_NAME=$(jq -r --arg id "$PR_AUTHOR_GITHUB_ID" '.[$id].name // "알 수 없음"' .github/memberMap.json)
           echo "pr_author_name=$PR_AUTHOR_NAME" >> $GITHUB_OUTPUT
 
-          # PR 작성자 제외한 멤버들의 slackId를 멘션으로 모으기
-          MENTIONS=$(jq -r --arg author "$PR_AUTHOR_GITHUB_ID" 'to_entries | map(select(.key != $author)) | map("<@" + .value.slackId + ">") | join(" ")' memberMap.json)
+          # PR 작성자 제외한 멤버들의 slackId를 멘션으로 모으기 (slackId가 있는 경우만)
+          MENTIONS=$(jq -r --arg author "$PR_AUTHOR_GITHUB_ID" '
+            to_entries 
+            | map(select(.key != $author and .value.slackId != null and .value.slackId != "")) 
+            | map("<@" + .value.slackId + ">") 
+            | join(" ")
+          ' .github/memberMap.json)
+
+          # 멘션이 없으면 빈 문자열로 설정
+          if [ -z "$MENTIONS" ] || [ "$MENTIONS" = "null" ]; then
+            MENTIONS=""
+          fi
           echo "reviewers_mention=$MENTIONS" >> $GITHUB_OUTPUT
 
       - name: Send Slack message
diff --git a/src/components/payment/paymentActionClient.tsx b/src/components/payment/paymentActionClient.tsx
index 12a4accb..44df25fb 100644
--- a/src/components/payment/paymentActionClient.tsx
+++ b/src/components/payment/paymentActionClient.tsx
@@ -116,8 +116,21 @@ export default function PaymentCheckoutPage({ study }: Props) {
 
         // 회원 결제
         // @docs https://docs.tosspayments.com/sdk/v2/js#tosspaymentspayment
+        // customerKey 형식: 영문 대소문자, 숫자, 특수문자 -, _, =, ., @로 2자 이상 50자 이하
+        // memberId를 안전한 형식으로 변환 (예: 기존 123 -> 변경 후 member-123)
+        const customerKey = `member-${study.memberId}`.replace(
+          /[^a-zA-Z0-9\-_=.@]/g,
+          '',
+        );
+
+        // Toss 에서 2자이상 50자이하 문자열을 요구함
+        if (customerKey.length < 2 || customerKey.length > 50) {
+          throw new Error(
+            `customerKey가 유효하지 않습니다: ${customerKey} (길이: ${customerKey.length})`,
+          );
+        }
         const payment = tossPayments.payment({
-          customerKey: String(study.memberId),
+          customerKey,
         });
 
         setPayment(payment);