diff --git a/alembic/versions/invite_code_and_relation.py b/alembic/versions/invite_code_and_relation.py
new file mode 100644
index 0000000..b89a29a
--- /dev/null
+++ b/alembic/versions/invite_code_and_relation.py
@@ -0,0 +1,54 @@
+"""user.invite_code + invite_relation table
+
+Revision ID: invite_code_and_relation
+Revises: 11a1d08c6f55
+Create Date: 2026-06-08 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'invite_code_and_relation'
+down_revision: Union[str, Sequence[str], None] = '11a1d08c6f55'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # user 加邀请码列(唯一索引;nullable 允许多个 NULL=未生成的用户)
+    with op.batch_alter_table('user', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('invite_code', sa.String(length=16), nullable=True))
+        batch_op.create_index('ix_user_invite_code', ['invite_code'], unique=True)
+
+    # 邀请关系表
+    op.create_table(
+        'invite_relation',
+        sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column('inviter_user_id', sa.Integer(), nullable=False),
+        sa.Column('invitee_user_id', sa.Integer(), nullable=False),
+        sa.Column('channel', sa.String(length=16), nullable=False, server_default='clipboard'),
+        sa.Column('status', sa.String(length=16), nullable=False, server_default='effective'),
+        sa.Column('inviter_coin', sa.Integer(), nullable=False, server_default='0'),
+        sa.Column('invitee_coin', sa.Integer(), nullable=False, server_default='0'),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.ForeignKeyConstraint(['inviter_user_id'], ['user.id']),
+        sa.ForeignKeyConstraint(['invitee_user_id'], ['user.id']),
+        sa.PrimaryKeyConstraint('id'),
+    )
+    op.create_index('ix_invite_relation_inviter_user_id', 'invite_relation', ['inviter_user_id'])
+    op.create_index('ix_invite_relation_invitee_user_id', 'invite_relation', ['invitee_user_id'], unique=True)
+    op.create_index('ix_invite_relation_created_at', 'invite_relation', ['created_at'])
+
+
+def downgrade() -> None:
+    op.drop_index('ix_invite_relation_created_at', table_name='invite_relation')
+    op.drop_index('ix_invite_relation_invitee_user_id', table_name='invite_relation')
+    op.drop_index('ix_invite_relation_inviter_user_id', table_name='invite_relation')
+    op.drop_table('invite_relation')
+    with op.batch_alter_table('user', schema=None) as batch_op:
+        batch_op.drop_index('ix_user_invite_code')
+        batch_op.drop_column('invite_code')
diff --git a/app/api/v1/invite.py b/app/api/v1/invite.py
new file mode 100644
index 0000000..2bbb857
--- /dev/null
+++ b/app/api/v1/invite.py
@@ -0,0 +1,64 @@
+"""好友邀请 endpoint。
+
+路由前缀 /api/v1/invite,需 Bearer 鉴权(用户级数据):
+  GET  /me     我的邀请码 + 分享链接 + 已邀人数/已得金币(邀请页展示)
+  POST /bind   把当前登录用户(被邀请人)绑定到某邀请码,注册即生效,双方各发金币
+
+客户端两种调用 /bind:
+  - 自动:首启读剪贴板拿到邀请码 → 登录后调本接口(channel=clipboard)
+  - 手动:用户在邀请页输入好友邀请码(channel=manual)
+
+绑定的真正逻辑(邀请码生成/反查、幂等、自邀屏蔽、发金币)在 repositories/invite.py。
+"""
+from __future__ import annotations
+
+import logging
+
+from fastapi import APIRouter
+
+from app.api.deps import CurrentUser, DbSession
+from app.core.config import settings
+from app.repositories import invite as invite_repo
+from app.schemas.invite import BindInviteIn, BindInviteOut, InviteInfoOut
+
+logger = logging.getLogger("shagua.invite")
+
+router = APIRouter(prefix="/api/v1/invite", tags=["invite"])
+
+_BIND_MESSAGES = {
+    "success": "邀请绑定成功,金币已到账",
+    "already_bound": "你已绑定过邀请人",
+    "invalid_code": "邀请码无效",
+    "self_invite": "不能填写自己的邀请码",
+    "not_eligible": "邀请仅对新注册用户生效",
+}
+
+
+@router.get("/me", response_model=InviteInfoOut, summary="我的邀请码 + 分享链接 + 战绩")
+def my_invite(user: CurrentUser, db: DbSession) -> InviteInfoOut:
+    code = invite_repo.ensure_code(db, user)
+    invited, coins = invite_repo.get_stats(db, user.id)
+    sep = "&" if "?" in settings.INVITE_LANDING_URL else "?"
+    share_url = f"{settings.INVITE_LANDING_URL}{sep}ref={code}"
+    return InviteInfoOut(
+        invite_code=code,
+        share_url=share_url,
+        invited_count=invited,
+        coins_earned=coins,
+    )
+
+
+@router.post("/bind", response_model=BindInviteOut, summary="绑定邀请人(注册即生效,双方发金币)")
+def bind_invite(req: BindInviteIn, user: CurrentUser, db: DbSession) -> BindInviteOut:
+    result = invite_repo.bind(
+        db, invitee=user, invite_code=req.invite_code, channel=req.channel,
+    )
+    logger.info(
+        "invite bind invitee=%d code=%s channel=%s -> %s",
+        user.id, req.invite_code, req.channel, result.status,
+    )
+    return BindInviteOut(
+        status=result.status,
+        coins_awarded=result.invitee_coin,
+        message=_BIND_MESSAGES.get(result.status, result.status),
+    )
diff --git a/app/core/config.py b/app/core/config.py
index c6eff5d..7daebd0 100644
--- a/app/core/config.py
+++ b/app/core/config.py
@@ -173,6 +173,11 @@ class Settings(BaseSettings):
     MEDIA_URL_PREFIX: str = "/media"
     AVATAR_MAX_BYTES: int = 5 * 1024 * 1024  # 头像最大 5MB
 
+    # ===== 邀请好友 =====
+    # 分享落地页(二维码 / 分享链接指向这里;扫码 → 落地页 → 引导浏览器下载 APK)。
+    # MVP 落地页就放 app-server 的 /media 静态目录下(dl.html)。
+    INVITE_LANDING_URL: str = "https://app-api.shaguabijia.com/media/dl.html"
+
     # ===== CORS =====
     CORS_ALLOW_ORIGINS: str = ""
 
diff --git a/app/core/rewards.py b/app/core/rewards.py
index 2d06c31..88f70c8 100644
--- a/app/core/rewards.py
+++ b/app/core/rewards.py
@@ -77,6 +77,15 @@ def record_milestone_reward(milestone: int) -> int:
     return RECORD_MILESTONES[milestone - 1]
 
 
+# ===== 邀请好友(注册即生效,邀请人 + 被邀请人各发金币)=====
+# 10000 金币 = 1 元,双方各得 1 元。MVP 先用固定常量(不走 app_config)。
+INVITE_INVITER_COINS: int = 10000
+INVITE_INVITEE_COINS: int = 10000
+# "新用户闸":被邀请人必须在注册后此窗口内绑定才发奖(挡存量老用户互相填码薅羊毛)。
+# 自动绑(剪贴板)在首次注册登录后几秒内发生;留 72h 给手动填码兜底。
+INVITE_NEW_USER_WINDOW_HOURS: int = 72
+
+
 # ===== 看激励视频 / 信息流广告发金币 =====
 # 金币数值体系约定:eCPM 单位按"元/千次展示"处理,单次收入 = eCPM / 1000 元。
 AD_ECPM_FACTOR_TABLE: tuple[tuple[float, int, int | None], ...] = (
diff --git a/app/main.py b/app/main.py
index 751a5d8..b905b93 100644
--- a/app/main.py
+++ b/app/main.py
@@ -22,6 +22,7 @@ from app.api.v1.compare_record import router as compare_record_router
 from app.api.v1.coupon import router as coupon_router
 from app.api.internal.price import router as internal_price_router
 from app.api.v1.feedback import router as feedback_router
+from app.api.v1.invite import router as invite_router
 from app.api.v1.meituan import router as meituan_router
 from app.api.v1.order import router as order_router
 from app.api.v1.platform import router as platform_router
@@ -79,6 +80,7 @@ def health() -> dict[str, str]:
 app.include_router(auth_router)
 app.include_router(user_router)
 app.include_router(feedback_router)
+app.include_router(invite_router)
 app.include_router(coupon_router)
 app.include_router(compare_router)
 app.include_router(compare_record_router)
diff --git a/app/models/__init__.py b/app/models/__init__.py
index 2f95779..9bab636 100644
--- a/app/models/__init__.py
+++ b/app/models/__init__.py
@@ -8,6 +8,7 @@ from app.models.app_config import AppConfig  # noqa: F401
 from app.models.comparison import ComparisonRecord  # noqa: F401
 from app.models.comparison_milestone import ComparisonMilestoneClaim  # noqa: F401
 from app.models.feedback import Feedback  # noqa: F401
+from app.models.invite import InviteRelation  # noqa: F401
 from app.models.meituan_coupon import MeituanCoupon  # noqa: F401
 from app.models.ops_marquee_seed import OpsMarqueeSeed  # noqa: F401
 from app.models.ops_stat_config import OpsStatConfig  # noqa: F401
diff --git a/app/models/invite.py b/app/models/invite.py
new file mode 100644
index 0000000..8ed6951
--- /dev/null
+++ b/app/models/invite.py
@@ -0,0 +1,46 @@
+"""好友邀请关系表(注册即生效)。
+
+一行 = 一次成功的邀请绑定。`invitee_user_id` 唯一 = 一个被邀请人只能被归因一次
+(天然幂等键,防重复发奖,仿 ad_reward.trans_id 思路)。`channel` 记归因来源
+(clipboard 自动 / manual 手动填),便于后续分析"剪贴板自动捕获率"。
+
+邀请码本身是 `user.invite_code`(一人一稳定码,懒生成),不在这张表里。
+"""
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy import DateTime, ForeignKey, Integer, String, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.db.base import Base
+
+
+class InviteRelation(Base):
+    __tablename__ = "invite_relation"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    inviter_user_id: Mapped[int] = mapped_column(
+        Integer, ForeignKey("user.id"), index=True, nullable=False
+    )
+    # 被邀请人唯一:一个人只能被邀一次(幂等键,防重复发奖)
+    invitee_user_id: Mapped[int] = mapped_column(
+        Integer, ForeignKey("user.id"), unique=True, index=True, nullable=False
+    )
+    # 归因来源:clipboard(剪贴板自动) / manual(手动填码)
+    channel: Mapped[str] = mapped_column(String(16), nullable=False, default="clipboard")
+    # 状态:effective(注册即生效)。预留:以后改"完成首单才生效"时用 pending/effective
+    status: Mapped[str] = mapped_column(String(16), nullable=False, default="effective")
+    # 本次给邀请人 / 被邀请人各发的金币(记账留痕,便于对账)
+    inviter_coin: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    invitee_coin: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), index=True, nullable=False
+    )
+
+    def __repr__(self) -> str:  # pragma: no cover
+        return (
+            f"<InviteRelation inviter={self.inviter_user_id} "
+            f"invitee={self.invitee_user_id} {self.status}>"
+        )
diff --git a/app/models/user.py b/app/models/user.py
index bf4be86..2f1d672 100644
--- a/app/models/user.py
+++ b/app/models/user.py
@@ -33,6 +33,12 @@ class User(Base):
     nickname: Mapped[str | None] = mapped_column(String(64), nullable=True)
     avatar_url: Mapped[str | None] = mapped_column(String(512), nullable=True)
 
+    # 邀请码:每个用户一个稳定短码(懒生成,见 repositories/invite.ensure_code),
+    # 分享链接 / 二维码里带它。unique 允许多个 NULL(未生成的用户)。
+    invite_code: Mapped[str | None] = mapped_column(
+        String(16), unique=True, index=True, nullable=True
+    )
+
     # 微信开放平台 openid(微信登录绑定后存,提现转账到零钱用)。同一 appid 下唯一;
     # unique 索引保证一个微信只能绑一个账号(nullable,允许多个 NULL=未绑定)。
     wechat_openid: Mapped[str | None] = mapped_column(
diff --git a/app/repositories/invite.py b/app/repositories/invite.py
new file mode 100644
index 0000000..8d496dd
--- /dev/null
+++ b/app/repositories/invite.py
@@ -0,0 +1,166 @@
+"""好友邀请 CRUD(注册即生效,邀请人 + 被邀请人各发金币)。
+
+防重复发奖三道(仿 ad_reward / 提现的资金安全思路):
+  1. invitee_user_id 唯一 → 一个被邀请人只能被绑定一次(幂等键)。
+  2. 自邀屏蔽 → inviter == invitee 直接拒。
+  3. 现成的手机号唯一(每个被邀请人 = 一个真实手机号账号)= 天然限制刷量规模。
+
+发金币复用 wallet.grant_coins(grant 只 flush 不 commit),与建关系记录在**同一事务**
+commit,保证"建关系 + 双方加金币"原子。奖励额 = rewards.INVITE_INVITER_COINS /
+INVITE_INVITEE_COINS。
+"""
+from __future__ import annotations
+
+import secrets
+from dataclasses import dataclass
+from datetime import datetime, timedelta, timezone
+
+from sqlalchemy import func, select
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.orm import Session
+
+from app.core import rewards
+from app.models.invite import InviteRelation
+from app.models.user import User
+from app.repositories import wallet as crud_wallet
+
+# 邀请码字符集:去掉易混字符(0/O/1/I/L/B/8/S/5/Z/2),用户口述/手输不易错
+_CODE_ALPHABET = "ACDEFGHJKMNPQRTUVWXY34679"
+_CODE_LEN = 6
+
+
+def _gen_code() -> str:
+    return "".join(secrets.choice(_CODE_ALPHABET) for _ in range(_CODE_LEN))
+
+
+def ensure_code(db: Session, user: User) -> str:
+    """保证 user 有邀请码(懒生成),返回它。唯一约束碰撞则换码重试。
+
+    ⚠️ 本函数会 db.commit() 整个 session(与 grant_coins"只 flush 不 commit"约定相反)。
+    当前只在 GET /invite/me 里调(该请求此前无其它写,提交范围干净)。若将来在带其它未提交
+    写的请求里复用本函数,会被它提前 commit——届时应改成 flush + 由调用方 commit。
+    """
+    if user.invite_code:
+        return user.invite_code
+    for _ in range(8):
+        user.invite_code = _gen_code()
+        try:
+            db.commit()
+            db.refresh(user)
+            return user.invite_code
+        except IntegrityError:
+            db.rollback()
+            user = db.get(User, user.id)  # 重取(rollback 后实例已过期),继续换码
+    raise RuntimeError("生成邀请码连续碰撞,请重试")
+
+
+def resolve_inviter(db: Session, invite_code: str) -> User | None:
+    """邀请码 → 邀请人(大小写不敏感)。"""
+    code = (invite_code or "").strip().upper()
+    if not code:
+        return None
+    return db.execute(
+        select(User).where(User.invite_code == code)
+    ).scalar_one_or_none()
+
+
+def _relation_of_invitee(db: Session, invitee_id: int) -> InviteRelation | None:
+    return db.execute(
+        select(InviteRelation).where(InviteRelation.invitee_user_id == invitee_id)
+    ).scalar_one_or_none()
+
+
+def _is_new_user(user: User) -> bool:
+    """被邀请人是否为"新注册"(created_at 在 INVITE_NEW_USER_WINDOW_HOURS 窗口内)。
+
+    "新用户闸":只奖刚注册的人,挡存量老用户互相填码薅羊毛。兼容 PG(tz-aware)与
+    SQLite(naive,按 UTC 解释)。
+    """
+    created = user.created_at
+    if created is None:
+        return False
+    if created.tzinfo is None:
+        created = created.replace(tzinfo=timezone.utc)
+    age = datetime.now(timezone.utc) - created
+    return age <= timedelta(hours=rewards.INVITE_NEW_USER_WINDOW_HOURS)
+
+
+@dataclass
+class BindResult:
+    status: str                          # success / already_bound / invalid_code / self_invite / not_eligible
+    relation: InviteRelation | None = None
+    invitee_coin: int = 0                # 本次给被邀请人发的金币(success 时 >0)
+
+
+def bind(
+    db: Session, *, invitee: User, invite_code: str, channel: str = "clipboard"
+) -> BindResult:
+    """把 invitee 绑定到 invite_code 对应的邀请人,注册即生效 + 双方发金币。
+
+    幂等:invitee 已被绑过 → already_bound(不重复发奖)。
+    """
+    # 幂等:已绑过直接返回(不重复发奖)
+    existing = _relation_of_invitee(db, invitee.id)
+    if existing is not None:
+        return BindResult("already_bound", existing)
+
+    inviter = resolve_inviter(db, invite_code)
+    if inviter is None or inviter.status != "active":
+        return BindResult("invalid_code")
+    if inviter.id == invitee.id:
+        return BindResult("self_invite")
+    # 新用户闸:被邀请人必须是"新注册"(窗口内)才发奖,挡存量老用户互相填码薅羊毛
+    if not _is_new_user(invitee):
+        return BindResult("not_eligible")
+
+    inviter_coin = rewards.INVITE_INVITER_COINS
+    invitee_coin = rewards.INVITE_INVITEE_COINS
+
+    rel = InviteRelation(
+        inviter_user_id=inviter.id,
+        invitee_user_id=invitee.id,
+        channel=(channel or "clipboard")[:16],
+        status="effective",
+        inviter_coin=inviter_coin,
+        invitee_coin=invitee_coin,
+    )
+    db.add(rel)
+    # 双方发金币(同事务,与建关系一起 commit)。ref_id 互指对方便于对账。
+    crud_wallet.grant_coins(
+        db, inviter.id, inviter_coin,
+        biz_type="invite_inviter", ref_id=str(invitee.id), remark="邀请好友奖励",
+    )
+    crud_wallet.grant_coins(
+        db, invitee.id, invitee_coin,
+        biz_type="invite_invitee", ref_id=str(inviter.id), remark="新人受邀奖励",
+    )
+    try:
+        db.commit()
+    except IntegrityError:
+        # 并发:同一 invitee 另一个请求先建了关系 → 回滚返回已存在(幂等兜底)
+        db.rollback()
+        existing = _relation_of_invitee(db, invitee.id)
+        if existing is not None:
+            return BindResult("already_bound", existing)
+        raise
+    except Exception:
+        # 其它 commit 失败(DB 故障 / PG 序列化冲突等):显式回滚,保证"建关系 + 双方发币"
+        # 原子(要么全成要么全无),不依赖 get_db 关闭时的隐式回滚,语义更硬。
+        db.rollback()
+        raise
+    db.refresh(rel)
+    return BindResult("success", rel, invitee_coin)
+
+
+def get_stats(db: Session, inviter_id: int) -> tuple[int, int]:
+    """返回 (已成功邀请人数, 累计从邀请获得的金币)。"""
+    count = db.execute(
+        select(func.count())
+        .select_from(InviteRelation)
+        .where(InviteRelation.inviter_user_id == inviter_id)
+    ).scalar_one()
+    coins = db.execute(
+        select(func.coalesce(func.sum(InviteRelation.inviter_coin), 0))
+        .where(InviteRelation.inviter_user_id == inviter_id)
+    ).scalar_one()
+    return int(count), int(coins)
diff --git a/app/schemas/invite.py b/app/schemas/invite.py
new file mode 100644
index 0000000..ecff181
--- /dev/null
+++ b/app/schemas/invite.py
@@ -0,0 +1,25 @@
+"""邀请相关 API 收发模型。"""
+from __future__ import annotations
+
+from pydantic import BaseModel, Field
+
+
+class InviteInfoOut(BaseModel):
+    invite_code: str                # 我的邀请码
+    share_url: str                  # 落地页链接(含 ?ref=),前端据此生成二维码 + 复制分享
+    invited_count: int              # 已成功邀请人数
+    coins_earned: int               # 累计从邀请获得的金币
+
+
+class BindInviteIn(BaseModel):
+    invite_code: str = Field(..., min_length=4, max_length=16, description="邀请人的邀请码")
+    channel: str = Field(
+        "clipboard", max_length=16,
+        description="归因来源:clipboard(首启读剪贴板自动) / manual(用户手动填)",
+    )
+
+
+class BindInviteOut(BaseModel):
+    status: str                     # success / already_bound / invalid_code / self_invite / not_eligible
+    coins_awarded: int              # 本次给当前用户(被邀请人)发的金币
+    message: str                    # 给前端直接展示的文案
diff --git a/tests/test_invite.py b/tests/test_invite.py
new file mode 100644
index 0000000..3064ef8
--- /dev/null
+++ b/tests/test_invite.py
@@ -0,0 +1,160 @@
+"""好友邀请测试:邀请码、绑定、双方发金币、幂等、自邀/无效码屏蔽。
+
+用 sms mock 登录拿 token(同 test_welfare),再跑邀请闭环。
+"""
+from __future__ import annotations
+
+from datetime import datetime, timedelta, timezone
+
+from app.core.rewards import (
+    INVITE_INVITEE_COINS,
+    INVITE_INVITER_COINS,
+    INVITE_NEW_USER_WINDOW_HOURS,
+)
+from app.db.session import SessionLocal
+from app.repositories.user import get_user_by_phone
+
+
+def _login(client, phone: str) -> str:
+    client.post("/api/v1/auth/sms/send", json={"phone": phone})
+    r = client.post("/api/v1/auth/sms/login", json={"phone": phone, "code": "123456"})
+    assert r.status_code == 200, r.text
+    return r.json()["access_token"]
+
+
+def _auth(token: str) -> dict[str, str]:
+    return {"Authorization": f"Bearer {token}"}
+
+
+def _coin_balance(client, token: str) -> int:
+    r = client.get("/api/v1/wallet/account", headers=_auth(token))
+    assert r.status_code == 200, r.text
+    return r.json()["coin_balance"]
+
+
+def _my_code(client, token: str) -> str:
+    r = client.get("/api/v1/invite/me", headers=_auth(token))
+    assert r.status_code == 200, r.text
+    return r.json()["invite_code"]
+
+
+def test_invite_me_returns_stable_code(client) -> None:
+    """/invite/me 返回邀请码 + 分享链接;同一用户多次取码稳定。"""
+    token = _login(client, "13800002001")
+    r = client.get("/api/v1/invite/me", headers=_auth(token))
+    assert r.status_code == 200, r.text
+    body = r.json()
+    assert body["invite_code"]                      # 非空
+    assert f"ref={body['invite_code']}" in body["share_url"]
+    assert body["invited_count"] == 0
+    assert body["coins_earned"] == 0
+    # 再取一次,码不变(懒生成 + 持久化)
+    assert _my_code(client, token) == body["invite_code"]
+
+
+def test_bind_flow_both_get_coins(client) -> None:
+    """B 用 A 的码绑定 → 双方各得 1 万金币;A 战绩 +1。"""
+    a = _login(client, "13800002002")
+    b = _login(client, "13800002003")
+    a_code = _my_code(client, a)
+
+    assert _coin_balance(client, a) == 0
+    assert _coin_balance(client, b) == 0
+
+    r = client.post("/api/v1/invite/bind", json={"invite_code": a_code}, headers=_auth(b))
+    assert r.status_code == 200, r.text
+    res = r.json()
+    assert res["status"] == "success"
+    assert res["coins_awarded"] == INVITE_INVITEE_COINS
+
+    # 双方金币到账
+    assert _coin_balance(client, b) == INVITE_INVITEE_COINS
+    assert _coin_balance(client, a) == INVITE_INVITER_COINS
+
+    # A 的战绩:已邀 1 人,累计获得 = 邀请人那份
+    r = client.get("/api/v1/invite/me", headers=_auth(a))
+    assert r.json()["invited_count"] == 1
+    assert r.json()["coins_earned"] == INVITE_INVITER_COINS
+
+
+def test_bind_idempotent_no_double_reward(client) -> None:
+    """同一被邀请人二次绑定 → already_bound,不重复发奖。"""
+    a = _login(client, "13800002004")
+    b = _login(client, "13800002005")
+    a_code = _my_code(client, a)
+
+    r1 = client.post("/api/v1/invite/bind", json={"invite_code": a_code}, headers=_auth(b))
+    assert r1.json()["status"] == "success"
+    bal_b = _coin_balance(client, b)
+    bal_a = _coin_balance(client, a)
+
+    # 再绑一次(甚至换个码也不行,已被绑过)
+    c = _login(client, "13800002006")
+    c_code = _my_code(client, c)
+    r2 = client.post("/api/v1/invite/bind", json={"invite_code": c_code}, headers=_auth(b))
+    assert r2.json()["status"] == "already_bound"
+    assert r2.json()["coins_awarded"] == 0
+
+    # 余额没变(没二次发奖),C 也没拿到邀请奖励
+    assert _coin_balance(client, b) == bal_b
+    assert _coin_balance(client, a) == bal_a
+    assert _coin_balance(client, c) == 0
+
+
+def test_self_invite_blocked(client) -> None:
+    """填自己的邀请码 → self_invite,不发奖。"""
+    a = _login(client, "13800002007")
+    a_code = _my_code(client, a)
+    r = client.post("/api/v1/invite/bind", json={"invite_code": a_code}, headers=_auth(a))
+    assert r.status_code == 200, r.text
+    assert r.json()["status"] == "self_invite"
+    assert _coin_balance(client, a) == 0
+
+
+def test_invalid_code(client) -> None:
+    """无效邀请码 → invalid_code,不发奖。"""
+    b = _login(client, "13800002008")
+    r = client.post("/api/v1/invite/bind", json={"invite_code": "ZZZZZZ"}, headers=_auth(b))
+    assert r.status_code == 200, r.text
+    assert r.json()["status"] == "invalid_code"
+    assert _coin_balance(client, b) == 0
+
+
+def test_manual_channel_recorded(client) -> None:
+    """channel=manual 也能绑定(手动填码兜底路径)。"""
+    a = _login(client, "13800002009")
+    b = _login(client, "13800002010")
+    a_code = _my_code(client, a)
+    r = client.post(
+        "/api/v1/invite/bind",
+        json={"invite_code": a_code, "channel": "manual"},
+        headers=_auth(b),
+    )
+    assert r.status_code == 200, r.text
+    assert r.json()["status"] == "success"
+
+
+def test_invite_requires_auth(client) -> None:
+    """不带 token → 401。"""
+    assert client.get("/api/v1/invite/me").status_code == 401
+    assert client.post("/api/v1/invite/bind", json={"invite_code": "ABCDEF"}).status_code == 401
+
+
+def test_old_user_not_eligible(client) -> None:
+    """新用户闸:被邀请人注册超过窗口 → not_eligible,双方都不发奖。"""
+    a = _login(client, "13800002030")
+    a_code = _my_code(client, a)
+    b = _login(client, "13800002031")
+    # 把 b 的注册时间改成超出窗口 → 变"老用户"
+    with SessionLocal() as db:
+        u = get_user_by_phone(db, "13800002031")
+        assert u is not None
+        u.created_at = datetime.now(timezone.utc) - timedelta(hours=INVITE_NEW_USER_WINDOW_HOURS + 1)
+        db.commit()
+
+    r = client.post("/api/v1/invite/bind", json={"invite_code": a_code}, headers=_auth(b))
+    assert r.status_code == 200, r.text
+    assert r.json()["status"] == "not_eligible"
+    assert r.json()["coins_awarded"] == 0
+    assert _coin_balance(client, b) == 0
+    assert _coin_balance(client, a) == 0