diff --git a/bin/check-nomad-badge.ts b/bin/check-nomad-badge.ts
new file mode 100644
index 0000000..e1a86de
--- /dev/null
+++ b/bin/check-nomad-badge.ts
@@ -0,0 +1,11 @@
+#!/usr/bin/env -S node --trace-warnings --loader ts-node/esm
+
+import { checkNomadBadge } from "../lib/check-nomad-badge.js";
+
+async function main() {
+  const args = process.argv.slice(2);
+
+  await checkNomadBadge();
+}
+
+main().catch((err) => console.error(new Date(), "ERROR:", err));
diff --git a/handlers/check-nomad-badge.ts b/handlers/check-nomad-badge.ts
new file mode 100644
index 0000000..faf3aab
--- /dev/null
+++ b/handlers/check-nomad-badge.ts
@@ -0,0 +1,26 @@
+import { Context, APIGatewayProxyResult, APIGatewayEvent } from "aws-lambda";
+import { checkNomadBadge } from "../lib/check-nomad-badge.js";
+
+export const handler = async (
+  event: APIGatewayEvent & {
+    campaignTagIds?: number[];
+    campaignBegins?: Date | string;
+    campaignEnds?: Date | string;
+  },
+  context: Context
+): Promise<APIGatewayProxyResult> => {
+  console.log(`Event: %o`, event);
+  console.log(`Context: %o`, context);
+
+  const { campaignTagIds, campaignBegins, campaignEnds } = event;
+  const retBadges = await checkNomadBadge({
+    campaignTagIds,
+    campaignBegins,
+    campaignEnds,
+  });
+
+  return {
+    statusCode: 200,
+    body: JSON.stringify({ message: "done.", retBadges }),
+  };
+};
diff --git a/lib/check-nomad-badge.ts b/lib/check-nomad-badge.ts
new file mode 100644
index 0000000..b00feaa
--- /dev/null
+++ b/lib/check-nomad-badge.ts
@@ -0,0 +1,312 @@
+import type { Language } from "./types";
+import { Mail } from "./mail.js";
+import { sql, sqlSIW } from "../lib/db.js";
+import { DAY, EMAIL_FROM_ASK } from "./constants/index.js";
+
+const siteDomain = process.env.MATTERS_SITE_DOMAIN || "";
+const newFeatureTagId = process.env.MATTERS_NEW_FEATURE_TAG_ID || "";
+const isProd = siteDomain === "https://matters.town";
+
+const mail = new Mail();
+
+const MATTERS_CAMPAIGN_TAGS_IDS = JSON.parse(
+  process.env.MATTERS_CAMPAIGN_TAGS_IDS || "[157201]"
+); // https://matters.town/tags/157201-nomadmatters?type=latest
+const MATTERS_CAMPAIGN_BEGINS =
+  process.env.MATTERS_CAMPAIGN_BEGINS || "2023-12-14T16:00:00.000Z"; // 2023-12-15T00:00 in UTC+8
+const MATTERS_CAMPAIGN_ENDS =
+  process.env.MATTERS_CAMPAIGN_ENDS || "2024-01-14T15:59:59.999Z"; // 2024-01-15T23:59 in UTC+8
+
+const ARRAY_TYPE = 1009; // Postgres internal value shouldn't be here;
+
+export async function checkNomadBadge({
+  campaignTagIds = MATTERS_CAMPAIGN_TAGS_IDS, // [157201],// https://matters.town/tags/157201-nomadmatters?type=latest
+  campaignBegins,
+  campaignEnds,
+  dryRun = true,
+}: {
+  campaignTagIds?: number[];
+  campaignBegins?: Date | string;
+  campaignEnds?: Date | string;
+  dryRun?: boolean;
+} = {}): Promise<any> {
+  // const [{ version, now }] = await sql` SELECT VERSION(), NOW() `; console.log("pgres:", { version, now });
+
+  if (!campaignBegins) campaignBegins = new Date(MATTERS_CAMPAIGN_BEGINS);
+  if (!campaignEnds) campaignEnds = new Date(MATTERS_CAMPAIGN_ENDS);
+  // const nomadTagId = 157201; // https://matters.town/tags/157201-nomadmatters?type=latest
+  // if (!campaignBegins || !campaignEnds) return;
+
+  const referrals = await sql`-- select all referred users
+SELECT referral_user_name, count, latest_referred
+FROM (
+  SELECT extra->>'referralCode' AS referral_user_name, COUNT(*) ::int, MAX(updated_at) AS latest_referred
+  FROM public.user
+  WHERE created_at BETWEEN ${campaignBegins} AND ${campaignEnds}
+    AND extra->'referralCode' IS NOT NULL
+  GROUP BY 1
+  -- HAVING COUNT(*) >=5
+) t
+JOIN public.user u ON referral_user_name=user_name -- use INNER JOIN; the referral_code must be existing user_names
+WHERE COALESCE((u.extra->'referredCount')::int, 0) < count
+ORDER BY latest_referred DESC, count DESC -- LIMIT 13 `;
+  console.log("log user by referrals:", referrals);
+  const referralsMap = new Map<string, number>(
+    referrals.map(({ referralUserName, count }) => [referralUserName, count])
+  );
+
+  // update eacho user's referCount
+  if (!dryRun) {
+    const usersWithUpdatedRefCount = await sqlSIW`-- upsert all new badges
+UPDATE public.user u SET
+  extra=COALESCE(u.extra, '{}'::jsonb) - '{removeKeys}'::text[] || t.extra, updated_at=CURRENT_TIMESTAMP
+FROM (
+  SELECT * FROM UNNEST(
+    ${sqlSIW.array(
+      referrals.map(({ referralUserName }) => referralUserName),
+      ARRAY_TYPE
+    )} ::text[],
+    ${sqlSIW.array(
+      referrals.map(({ count, latestReferred }) =>
+        JSON.stringify({ referredCount: count, latestReferred })
+      ),
+      ARRAY_TYPE
+    )} ::jsonb[]
+  )
+) AS t(user_name, extra)
+WHERE u.user_name=t.user_name -- skip AND u.extra->'referredCount' < t.extra->'referredCount'
+RETURNING u.* ;`;
+
+    console.log("log user by referrals:", usersWithUpdatedRefCount);
+
+    // return;
+  }
+
+  const allParticipants = await sql`-- query all campaign applicants
+WITH all_applicant_articles AS (
+  SELECT DISTINCT ON (author_id)
+    author_id ::int, article.id ::int, article.title, article.created_at
+  FROM article_tag
+  LEFT JOIN public.article ON article_id=article.id
+  WHERE article.created_at BETWEEN ${campaignBegins!} AND ${campaignEnds!}
+    AND tag_id =ANY(${campaignTagIds})
+  ORDER BY author_id, article.created_at DESC
+), all_apprs_to_applicants AS (
+  SELECT DISTINCT ON (sender_id) sender_id ::int, created_at
+  FROM appreciation
+  WHERE reference_id IN ( SELECT id FROM all_applicant_articles )
+    AND purpose IN ('appreciate')
+    AND created_at BETWEEN ${campaignBegins!} AND ${campaignEnds!}
+  ORDER BY sender_id, created_at DESC
+), all_donations_to_applicants AS (
+  SELECT DISTINCT ON (sender_id) sender_id ::int, created_at
+  FROM transaction
+  WHERE purpose='donation' AND state='succeeded'
+    AND target_type=4 AND target_id IN ( SELECT id FROM all_applicant_articles )
+    AND created_at BETWEEN ${campaignBegins!} AND ${campaignEnds!}
+  ORDER BY sender_id, created_at DESC
+), merged_all AS (
+  SELECT DISTINCT ON (user_id) user_id, last_act, last_act_at
+  FROM (
+    SELECT author_id ::int AS user_id, 'article_applicant' AS last_act, created_at AS last_act_at FROM all_applicant_articles
+    UNION ALL
+    SELECT sender_id ::int AS user_id, 'appr_to_applicant' AS last_act, created_at AS last_act_at FROM all_apprs_to_applicants
+    UNION ALL
+    SELECT sender_id ::int AS user_id, 'donate_to_applicant' AS last_act, created_at AS last_act_at FROM all_donations_to_applicants
+  ) t
+  ORDER BY user_id, last_act_at DESC
+)
+
+SELECT user_name, display_name, aa.*,
+  u.email, u.language, u.created_at, u.state,
+  COALESCE((ub.extra->'level')::int, 0) AS current_level -- current nomad badge level
+FROM merged_all aa
+LEFT JOIN public.user u ON aa.user_id=u.id
+LEFT JOIN public.user_badge ub ON ub.user_id=aa.user_id AND ub.type='nomad'
+ORDER BY aa.last_act_at DESC ; `;
+
+  console.log("consider all applicants:", allParticipants);
+
+  const newNomad1BadgedUsers = allParticipants
+    .filter(
+      ({ currentLevel }) => currentLevel < 1 // && (referralsMap.get(userName) || 0) >= 0
+    ) // for all ones got Lv1
+    .map(({ userId, userName, displayName, email, language, ...rest }) => ({
+      userId,
+      type: "nomad" as const,
+      newLevel: 1 as const,
+      userName,
+      referredCount: referralsMap.get(userName) || 0,
+      displayName,
+      email,
+      language: language as Language,
+      ...rest,
+    }));
+
+  console.log("consider new nomad1 badges:", newNomad1BadgedUsers);
+  await putBadges(newNomad1BadgedUsers);
+  await sendNomadBadgeMail(newNomad1BadgedUsers);
+  // send badges, send mattersDB notification, send emails
+
+  const newNomad2BadgedUsers = allParticipants
+    .filter(
+      ({ userName, currentLevel }) =>
+        currentLevel < 2 && (referralsMap.get(userName) || 0) >= 5
+    ) // for all ones got Lv2
+    .map(({ userId, userName, displayName, email, language, ...rest }) => ({
+      userId,
+      type: "nomad" as const,
+      newLevel: 2 as const,
+      userName,
+      referredCount: referralsMap.get(userName) || 0,
+      displayName,
+      email,
+      language: language as Language,
+      ...rest,
+    }));
+
+  console.log("consider new nomad2 badges:", newNomad2BadgedUsers);
+  await putBadges(newNomad2BadgedUsers);
+  await sendNomadBadgeMail(newNomad2BadgedUsers);
+  // send badges, send mattersDB notification, send emails
+
+  const newNomad3BadgedUsers = allParticipants
+    .filter(
+      ({ userName, currentLevel }) =>
+        currentLevel < 3 && (referralsMap.get(userName) || 0) >= 10
+    ) // for all ones got Lv3
+    .map(({ userId, userName, displayName, email, language, ...rest }) => ({
+      userId,
+      type: "nomad" as const,
+      newLevel: 3 as const,
+      userName,
+      referredCount: referralsMap.get(userName) || 0,
+      displayName,
+      email,
+      language: language as Language,
+      ...rest,
+    }));
+
+  console.log("consider new nomad3 badges:", newNomad3BadgedUsers);
+  await putBadges(newNomad3BadgedUsers);
+  await sendNomadBadgeMail(newNomad3BadgedUsers);
+  // send badges, send mattersDB notification, send emails
+
+  const newNomad4BadgedUsers = allParticipants
+    .filter(
+      ({ userName, currentLevel }) =>
+        currentLevel < 4 && (referralsMap.get(userName) || 0) >= 20
+    ) // for all ones got Lv4
+    .map(({ userId, userName, displayName, email, language, ...rest }) => ({
+      userId,
+      type: "nomad" as const,
+      newLevel: 4 as const,
+      userName,
+      referredCount: referralsMap.get(userName) || 0,
+      displayName,
+      email,
+      language: language as Language,
+      ...rest,
+    }));
+
+  console.log("consider new nomad4 badged users:", newNomad4BadgedUsers);
+  await putBadges(newNomad4BadgedUsers);
+  await sendNomadBadgeMail(newNomad4BadgedUsers);
+
+  // send badges, send mattersDB notification, send emails
+
+  return;
+}
+
+async function putBadges(
+  newNomadBadges: Array<{
+    userId: number;
+    type: "nomad";
+    newLevel: 1 | 2 | 3 | 4;
+  }>,
+  dryRun = true
+) {
+  if (dryRun) return;
+
+  const retBadges = await sqlSIW`-- upsert all new badges
+INSERT INTO public.user_badge AS ub(user_id, type, extra)
+  SELECT * FROM UNNEST(
+    ${sqlSIW.array(
+      newNomadBadges.map(({ userId }) => userId),
+      ARRAY_TYPE
+    )} ::int[],
+    ${sqlSIW.array(
+      newNomadBadges.map(({ type }) => type),
+      ARRAY_TYPE
+    )} ::text[],
+    ${sqlSIW.array(
+      newNomadBadges.map(({ newLevel }) => JSON.stringify({ level: newLevel })),
+      ARRAY_TYPE
+    )} ::jsonb[]
+  )
+ON CONFLICT (user_id, type)
+DO UPDATE
+  SET extra=((COALESCE(ub.extra, '{}' ::jsonb) - ${[
+    "removeKeys",
+  ]} ::text[]) || EXCLUDED.extra)
+RETURNING * ;
+`;
+
+  console.log("upsert'ed new badges:", retBadges);
+
+  // send msg queue for mail
+
+  return retBadges;
+}
+
+const getTemplateId = (language: Language): string => {
+  const templateIdsDev = {
+    zh_hant: "d-550c209eef09442d8430fed10379593a",
+    zh_hans: "d-22b0f1c254d74cadaf6b2d246e0b4c14",
+    en: "d-550c209eef09442d8430fed10379593a",
+  };
+  const templateIdsProd = {
+    zh_hant: "d-bc5695dcae564795ac76bc6a783a5ef7",
+    zh_hans: "d-7497ca1cfaa745a8bff4b3d20e92480a",
+    en: "d-bc5695dcae564795ac76bc6a783a5ef7",
+  };
+  const templateIds = isProd ? templateIdsProd : templateIdsDev;
+  return templateIds[language];
+};
+
+async function sendNomadBadgeMail(
+  newNomadBadgedUsers: Array<{
+    // userId: number; type: string; extra: any;
+    displayName: string;
+    email: string;
+    language: Language;
+    newLevel: 1 | 2 | 3 | 4;
+  }>,
+  dryRun = true
+) {
+  if (dryRun) return;
+
+  return Promise.allSettled(
+    newNomadBadgedUsers.map(({ displayName, email, language, newLevel }) => {
+      const shareLink = `https://matters.town/xxxxx/xxxxxx?xxxx=xxxxxx123`;
+
+      return mail.send({
+        from: EMAIL_FROM_ASK,
+        templateId: getTemplateId(language),
+        personalizations: [
+          {
+            to: email,
+            dynamicTemplateData: {
+              // subject,
+              displayName,
+              siteDomain,
+              shareLink,
+              newLevel,
+              // recipient, type,
+            },
+          },
+        ],
+      });
+    })
+  );
+}