diff --git a/sdk_demo.py b/sdk_demo.py
new file mode 100644
index 0000000..536c96f
--- /dev/null
+++ b/sdk_demo.py
@@ -0,0 +1,188 @@
+import copy
+from dataclasses import dataclass
+import re
+import json
+import time
+from typing import Optional, Union
+
+import requests
+import httpx
+
+
+@dataclass
+class ProjectMeta:
+    identifier: str
+    slug: str
+    icon: str
+    deadline: str
+@dataclass
+class ProjectStatus:
+    public: bool
+    paused: bool
+@dataclass
+class ProjectClient:
+    version: str
+    claim_task_delay: float
+    """ 客户端在 claim_task 之后，多久之后才能再次 claim_task （软限制）"""
+@dataclass
+class ProjectMongodb:
+    db_name: str
+    item_collection: str
+    queue_collection: str
+    custom_doc_id_name: str
+    """ TODO: 未来弃用 """
+@dataclass
+class Project:
+    meta: ProjectMeta
+    status: ProjectStatus
+    client: ProjectClient
+    mongodb: ProjectMongodb
+
+    def __init__(self, meta: dict, status: dict, client: dict, mongodb: dict):
+        self.meta = ProjectMeta(**meta)
+        self.status = ProjectStatus(**status)
+        self.client = ProjectClient(**client)
+        self.mongodb = ProjectMongodb(**mongodb)
+
+
+
+class Tracker:
+    API_BASE = "http://localhost:8080/"
+    API_VERSION = "v1"
+    client_version: str
+    project_id: str
+    """ [^a-zA-Z0-9_\\-] """
+    archivist: str
+    """ [^a-zA-Z0-9_\\-] """
+    session: requests.Session | httpx.Client | httpx.AsyncClient
+    project_id: str
+    __project: Project
+    __project_last_fetched: float = 0
+
+
+    def _is_safe_string(self, s: str):
+        r = re.compile(r"[^a-zA-Z0-9_\\-]")
+        return not r.search(s)
+
+    def __init__(self, project_id: str, client_version: str, archivist: str, session: requests.Session | httpx.Client | httpx.AsyncClient):
+        assert self._is_safe_string(project_id) and self._is_safe_string(archivist), "[^a-zA-Z0-9_\\-]"
+        self.project_id = project_id
+        self.client_version = client_version
+        self.archivist = archivist
+        self.session = session
+    
+    @property
+    def project(self):
+        """
+        return: Project, deep copy.
+        return __project cache if it's not expired (60s)
+        """
+        if time.time() - self.__project_last_fetched > 60:
+            self.__project = self.fetch_project()
+            self.__project_last_fetched = time.time()
+        return copy.deepcopy(self.__project)
+
+    def fetch_project(self):
+        """
+        return: Project, deep copy
+        also refresh __project cache
+        """
+        assert isinstance(self.session, (requests.Session, httpx.Client))
+        r = self.session.post(self.API_BASE + self.API_VERSION + '/project/' + self.project_id)
+        r.raise_for_status()
+        proj = Project(**r.json())
+        self.__project = copy.deepcopy(proj)
+        return proj
+
+    def get_projects(self):
+        assert isinstance(self.session, (requests.Session, httpx.Client))
+        r = self.session.post(self.API_BASE + self.API_VERSION + '/projects')
+        r.raise_for_status()
+        return [Project(**p) for p in r.json()]
+    
+    def validate_client_version(self):
+        assert isinstance(self.session, (requests.Session, httpx.Client))
+        if self.project.client.version != self.client_version:
+            return False
+        return True
+
+    def claim_task(self):
+        assert isinstance(self.session, (requests.Session, httpx.Client))
+        r = self.session.post(f'{self.API_BASE}{self.API_VERSION}/project/{self.project_id}/{self.client_version}/{self.archivist}/claim_task')
+        if r.status_code == 404:
+            return None # No tasks available
+        if r.status_code == 200:
+            return r.json()
+        raise Exception(r.text)
+    
+    def update_task(self, task_id: Union[str, int], status: str):
+        """
+        task_id: 必须明确传入的是 int 还是 str
+        status: 任务状态
+        """
+        assert isinstance(self.session, (requests.Session, httpx.Client))
+        assert isinstance(task_id, (str, int))
+        assert isinstance(status, str)
+        
+
+        r = self.session.post(
+            f'{self.API_BASE}{self.API_VERSION}/project/{self.project_id}/{self.client_version}/{self.archivist}/update_task/{task_id}', 
+            data={
+                'status': status,
+                'task_id_type': 'int' if isinstance(task_id, int) else 'str'
+            })
+        if r.status_code == 200:
+            return r.json()
+        raise Exception(r.text)
+    
+    def insert_item(self, item_id: Union[str, int], item_status: Optional[Union[str, int]] = None, payload: Optional[dict] = None):
+        """
+        item_id: 必须明确传入的是 int 还是 str
+        item_status: item 状态，而不是 task 状态。可用于标记一些被删除、被隐藏的 item 之类的。就不用添加一堆错误响应到 payload 里了。 
+        payload: 可以传入任意的可转为 ext-json 的对象 (包括 None)
+        """
+        assert isinstance(self.session, (requests.Session, httpx.Client))
+        # item_id_type
+        if isinstance(item_id, int):
+            item_id_type = 'int'
+        elif isinstance(item_id, str):
+            item_id_type = 'str'
+        else:
+            raise ValueError("item_id must be int or str")
+
+        if item_status is None:
+            status_type = "None"
+        elif isinstance(item_status, int):
+            status_type = "int"
+        elif isinstance(item_status, str):
+            status_type = "str"
+        else:
+            raise ValueError("status must be int, str or None")
+        r = self.session.post(
+            f'{self.API_BASE}{self.API_VERSION}/project/{self.project_id}/{self.client_version}/{self.archivist}/insert_item/{item_id}',
+            data={
+                'item_id_type': item_id_type,
+                'item_status': item_status,
+                'item_status_type': status_type,
+                'payload': json.dumps(payload, ensure_ascii=False, separators=(',', ':'))
+            })
+        if r.status_code == 200:
+            return r.json()
+        raise Exception(r.text)
+if __name__ == '__main__':
+    ss = requests.Session()
+    proj_id = 'test_proj'
+    tracker = Tracker(proj_id, '1.0','demo_tester', ss)
+    print(tracker.get_projects())
+    assert proj_id in [p.meta.identifier for p in tracker.get_projects()]
+    print(tracker.project)
+    task = tracker.claim_task()
+    print(task)
+    id_name = tracker.project.mongodb.custom_doc_id_name or 'id'
+    assert task
+    task_result = tracker.update_task(task_id=task[id_name], status='FAIL')
+    print(task_result)
+    payload = {'test_data': {'name': 'aaabbccc', 'id': 25}}
+    item_result = tracker.insert_item(item_id=task[id_name], item_status=1, payload=payload)
+    print(item_result)
+    # 12,625,984
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