diff --git a/models/base.py b/models/base.py
index edb84ad..eb5c8e1 100644
--- a/models/base.py
+++ b/models/base.py
@@ -1,7 +1,65 @@
-import uuid
-from sqlalchemy.orm import declarative_base
+import hashlib
+from sqlalchemy import Column, String
+from sqlalchemy.orm import declarative_base, declared_attr
+import ulid
 
 Base = declarative_base()
 
-def gen_uuid() -> str:
-    return str(uuid.uuid4())
\ No newline at end of file
+# Base62 字符集
+ALPHABET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+
+
+def encode_base62(num: int) -> str:
+    """将一个整数编码为 Base62 字符串"""
+    if num == 0:
+        return ALPHABET[0]
+    arr = []
+    base = len(ALPHABET)
+    while num:
+        num, rem = divmod(num, base)
+        arr.append(ALPHABET[rem])
+    return "".join(reversed(arr))
+
+
+def encode_tablename_to_prefix(tablename: str, length: int = 3) -> str:
+    """
+    将表名 encode 成固定长度的前缀，使用 MD5 拿到表名的唯一哈希值，转为整数后用 Base62 截取前 N 位
+    """
+    # 计算表名的 MD5 哈希
+    hasher = hashlib.md5(tablename.encode("utf-8"))
+    hex_digest = hasher.hexdigest()
+    
+    # 将十六进制哈希转为大整数
+    num = int(hex_digest, 16)
+    
+    # 转为 Base62 字符串
+    b62_str = encode_base62(num)
+    
+    # 截取固定长度（例如 3 位）作为该表的专属代码
+    return b62_str[:length]
+
+
+def gen_convex_payload() -> str:
+    """生成 128位 ULID 转 Base62 的趋势递增 Payload"""
+    u = ulid.new()
+    return encode_base62(u.int)
+
+
+class AutoID:
+    """
+    全自动 Convex 风格 ID 注入器
+    不再需要手动定义任何 prefix，全自动根据 __tablename__ 编码生成
+    """
+    @declared_attr
+    def id(cls):
+        # 运行时动态获取子类的 __tablename__
+        tablename = cls.__tablename__
+        
+        # 将表名编码为固定前缀（例如 "users" -> "7X1"）
+        table_prefix = encode_tablename_to_prefix(tablename, length=3)
+        
+        # 核心工厂函数：拼接【编码后的表前缀】和【递增Payload】
+        def id_factory():
+            return f"{table_prefix}_{gen_convex_payload()}"
+
+        return Column(String(32), primary_key=True, default=id_factory)
\ No newline at end of file
diff --git a/models/message.py b/models/message.py
new file mode 100644
index 0000000..1eead8e
--- /dev/null
+++ b/models/message.py
@@ -0,0 +1,11 @@
+from sqlalchemy import Column, DateTime, String, ForeignKey
+from sqlalchemy.sql import func
+from .base import Base, AutoID
+
+class Message(Base, AutoID):
+    __tablename__ = "messages"
+
+    user_id = Column(String, ForeignKey("users.id"), index=True)
+    content = Column(String)
+
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
\ No newline at end of file
diff --git a/models/user.py b/models/user.py
index e3331fe..e9ed6bc 100644
--- a/models/user.py
+++ b/models/user.py
@@ -1,13 +1,11 @@
 from sqlalchemy import Column, DateTime, String
 from sqlalchemy.sql import func
 
-from .base import Base, gen_uuid
+from .base import AutoID, Base
 
-class User(Base):
+class User(Base, AutoID):
     __tablename__ = "users"
 
-    id = Column(String, primary_key=True, default=gen_uuid)
-
     google_id = Column(String, unique=True, index=True)
     email = Column(String, unique=True, index=True)
     name = Column(String)
diff --git a/pyproject.toml b/pyproject.toml
index db42da5..16e8ccf 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,5 +9,6 @@ dependencies = [
     "httpx>=0.28.1",
     "python-jose>=3.5.0",
     "sqlalchemy>=2.0.49",
+    "ulid-py>=1.1.0",
     "uvicorn>=0.47.0",
 ]
diff --git a/uv.lock b/uv.lock
index 9d6cbf7..3871b0f 100644
--- a/uv.lock
+++ b/uv.lock
@@ -50,6 +50,7 @@ dependencies = [
     { name = "httpx" },
     { name = "python-jose" },
     { name = "sqlalchemy" },
+    { name = "ulid-py" },
     { name = "uvicorn" },
 ]
 
@@ -59,6 +60,7 @@ requires-dist = [
     { name = "httpx", specifier = ">=0.28.1" },
     { name = "python-jose", specifier = ">=3.5.0" },
     { name = "sqlalchemy", specifier = ">=2.0.49" },
+    { name = "ulid-py", specifier = ">=1.1.0" },
     { name = "uvicorn", specifier = ">=0.47.0" },
 ]
 
@@ -339,6 +341,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/dc/9b/47798a6c91d8bdb567fe2698fe81e0c6b7cb7ef4d13da4114b41d239f65d/typing_inspection-0.4.2-py3-none-any.whl", hash = "sha256:4ed1cacbdc298c220f1bd249ed5287caa16f34d44ef4e9c3d0cbad5b521545e7", size = 14611, upload-time = "2025-10-01T02:14:40.154Z" },
 ]
 
+[[package]]
+name = "ulid-py"
+version = "1.1.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/3b/53/d14a8ec344048e21431821cb49e9a6722384f982b889c2dd449428dbdcc1/ulid-py-1.1.0.tar.gz", hash = "sha256:dc6884be91558df077c3011b9fb0c87d1097cb8fc6534b11f310161afd5738f0", size = 22514, upload-time = "2020-09-15T15:35:09.414Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/42/7c/a12c879fe6c2b136a718c142115ff99397fbf62b4929d970d58ae386d55f/ulid_py-1.1.0-py2.py3-none-any.whl", hash = "sha256:b56a0f809ef90d6020b21b89a87a48edc7c03aea80e5ed5174172e82d76e3987", size = 25753, upload-time = "2020-09-15T15:35:08.075Z" },
+]
+
 [[package]]
 name = "uvicorn"
 version = "0.47.0"