diff --git a/packages/cli/src/commands/config.ts b/packages/cli/src/commands/config.ts
new file mode 100644
index 0000000..ed1cb70
--- /dev/null
+++ b/packages/cli/src/commands/config.ts
@@ -0,0 +1,28 @@
+import { Command } from "commander";
+import { loadConfig, saveConfig } from "../config.js";
+
+export function registerConfigCommand(program: Command) {
+  const cmd = program.command("config").description("Configure API endpoint and API Key");
+
+  cmd
+    .command("set <key> <value>")
+    .description("Set a config value (api-url or api-key)")
+    .action((key: string, value: string) => {
+      try {
+        saveConfig(key, value);
+        console.error(`Set ${key} successfully.`);
+      } catch (e: any) {
+        console.error(e.message);
+        process.exit(1);
+      }
+    });
+
+  cmd
+    .command("list")
+    .description("Show current configuration")
+    .action(() => {
+      const config = loadConfig();
+      console.log(`api-url: ${config.apiUrl || "(not set)"}`);
+      console.log(`api-key: ${config.apiKey ? config.apiKey.slice(0, 6) + "..." : "(not set)"}`);
+    });
+}
diff --git a/packages/cli/src/config.ts b/packages/cli/src/config.ts
new file mode 100644
index 0000000..3d5ce21
--- /dev/null
+++ b/packages/cli/src/config.ts
@@ -0,0 +1,56 @@
+import { existsSync, mkdirSync, readFileSync, writeFileSync } from "fs";
+import { homedir } from "os";
+import { join } from "path";
+
+export interface CliConfig {
+  apiUrl: string;
+  apiKey: string;
+}
+
+const CONFIG_DIR = join(homedir(), ".moemail");
+const CONFIG_FILE = join(CONFIG_DIR, "config.json");
+
+export function loadConfig(): CliConfig {
+  const config: CliConfig = { apiUrl: "", apiKey: "" };
+
+  // File config
+  if (existsSync(CONFIG_FILE)) {
+    try {
+      const raw = JSON.parse(readFileSync(CONFIG_FILE, "utf-8"));
+      if (raw.apiUrl) config.apiUrl = raw.apiUrl;
+      if (raw.apiKey) config.apiKey = raw.apiKey;
+    } catch {}
+  }
+
+  // Env overrides (higher priority)
+  if (process.env.MOEMAIL_API_URL) config.apiUrl = process.env.MOEMAIL_API_URL;
+  if (process.env.MOEMAIL_API_KEY) config.apiKey = process.env.MOEMAIL_API_KEY;
+
+  return config;
+}
+
+export function saveConfig(key: string, value: string): void {
+  if (!existsSync(CONFIG_DIR)) {
+    mkdirSync(CONFIG_DIR, { recursive: true });
+  }
+
+  let config: Record<string, string> = {};
+  if (existsSync(CONFIG_FILE)) {
+    try {
+      config = JSON.parse(readFileSync(CONFIG_FILE, "utf-8"));
+    } catch {}
+  }
+
+  const keyMap: Record<string, string> = {
+    "api-url": "apiUrl",
+    "api-key": "apiKey",
+  };
+
+  const configKey = keyMap[key];
+  if (!configKey) {
+    throw new Error(`Unknown config key: ${key}. Valid keys: api-url, api-key`);
+  }
+
+  config[configKey] = value;
+  writeFileSync(CONFIG_FILE, JSON.stringify(config, null, 2));
+}
diff --git a/packages/cli/src/index.ts b/packages/cli/src/index.ts
index d8f23d6..6c960e8 100644
--- a/packages/cli/src/index.ts
+++ b/packages/cli/src/index.ts
@@ -1,5 +1,6 @@
 #!/usr/bin/env node
 import { Command } from "commander";
+import { registerConfigCommand } from "./commands/config.js";
 
 const program = new Command();
 
@@ -9,4 +10,6 @@ program
   .version("0.1.0")
   .option("--json", "output as JSON");
 
+registerConfigCommand(program);
+
 program.parse();