diff --git a/.env.example b/.env.example
index 263306c..7d71cdf 100644
--- a/.env.example
+++ b/.env.example
@@ -21,7 +21,9 @@ REDIS_URL=redis://localhost:6379/0
 REDIS_REQUIRED=false
 
 # --- Security ---
-# Generate with: python -c "import secrets; print(secrets.token_urlsafe(48))"
+# Signs user-account JWT access tokens (app/core/auth.py) -- a weak or
+# leaked value lets anyone forge a valid login for any user id. Generate
+# with: python -c "import secrets; print(secrets.token_urlsafe(48))"
 AURORA_SECRET_KEY=changeme-generate-a-real-secret
 # Comma-separated API keys allowed to call /api/v1/admin/* endpoints.
 AURORA_ADMIN_API_KEYS=changeme-admin-key
diff --git a/app/api/deps.py b/app/api/deps.py
index 93e8024..55be39d 100644
--- a/app/api/deps.py
+++ b/app/api/deps.py
@@ -4,12 +4,44 @@ from __future__ import annotations
 
 from collections.abc import Awaitable, Callable
 
-from fastapi import HTTPException, status
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 from pydantic import BaseModel
 from redis.asyncio import Redis
+from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.core.auth import InvalidTokenError, decode_access_token
+from app.core.database import get_db
+from app.models.user import User
+from app.repositories.user_repository import get_user_by_id
 from app.services.cache import cache_get_json, cache_set_json
 
+_bearer_scheme = HTTPBearer(auto_error=False)
+
+
+def _unauthorized() -> HTTPException:
+    return HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail={"code": "not_authenticated", "message": "Missing or invalid access token."},
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+
+
+async def get_current_user(
+    credentials: HTTPAuthorizationCredentials | None = Depends(_bearer_scheme),
+    session: AsyncSession = Depends(get_db),
+) -> User:
+    if credentials is None:
+        raise _unauthorized()
+    try:
+        user_id = decode_access_token(credentials.credentials)
+    except InvalidTokenError as exc:
+        raise _unauthorized() from exc
+    user = await get_user_by_id(session, user_id)
+    if user is None or not user.is_active:
+        raise _unauthorized()
+    return user
+
 
 def not_found(entity_type: str, aurora_id_str: str) -> HTTPException:
     return HTTPException(
diff --git a/app/api/v1/auth.py b/app/api/v1/auth.py
new file mode 100644
index 0000000..4669382
--- /dev/null
+++ b/app/api/v1/auth.py
@@ -0,0 +1,68 @@
+"""Registration and login (section 17, additive). Public, but rate-limited
+like every other unauthenticated endpoint -- see app/core/security.py.
+"""
+
+from __future__ import annotations
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.api.deps import get_current_user
+from app.core.auth import create_access_token
+from app.core.database import get_db
+from app.core.ids import aurora_id
+from app.core.security import enforce_rate_limit
+from app.models.user import User
+from app.schemas.auth import LoginRequest, RegisterRequest, TokenOut, UserOut
+from app.services.user_service import (
+    EmailAlreadyRegisteredError,
+    InvalidCredentialsError,
+    authenticate_user,
+    register_user,
+)
+
+router = APIRouter(prefix="/auth", tags=["auth"], dependencies=[Depends(enforce_rate_limit)])
+
+
+def _to_user_out(user: User) -> UserOut:
+    return UserOut(
+        id=aurora_id("user", str(user.id)),
+        email=user.email,
+        display_name=user.display_name,
+        created_at=user.created_at,
+    )
+
+
+@router.post("/register", response_model=TokenOut, status_code=status.HTTP_201_CREATED)
+async def register(body: RegisterRequest, session: AsyncSession = Depends(get_db)) -> TokenOut:
+    try:
+        user = await register_user(
+            session, email=body.email, password=body.password, display_name=body.display_name
+        )
+    except EmailAlreadyRegisteredError as exc:
+        raise HTTPException(
+            status.HTTP_409_CONFLICT,
+            {"code": "email_already_registered", "message": "An account with this email already exists."},
+        ) from exc
+    await session.commit()
+    return TokenOut(access_token=create_access_token(user.id))
+
+
+@router.post("/login", response_model=TokenOut)
+async def login(body: LoginRequest, session: AsyncSession = Depends(get_db)) -> TokenOut:
+    try:
+        user = await authenticate_user(session, email=body.email, password=body.password)
+    except InvalidCredentialsError as exc:
+        # Deliberately identical whether the email doesn't exist or the
+        # password is wrong (see authenticate_user) -- distinguishing them
+        # here would let a client enumerate registered emails.
+        raise HTTPException(
+            status.HTTP_401_UNAUTHORIZED,
+            {"code": "invalid_credentials", "message": "Incorrect email or password."},
+        ) from exc
+    return TokenOut(access_token=create_access_token(user.id))
+
+
+@router.get("/me", response_model=UserOut)
+async def get_me(user: User = Depends(get_current_user)) -> UserOut:
+    return _to_user_out(user)
diff --git a/app/core/auth.py b/app/core/auth.py
new file mode 100644
index 0000000..33d4c3e
--- /dev/null
+++ b/app/core/auth.py
@@ -0,0 +1,75 @@
+"""Password hashing and JWT access tokens for registered users.
+
+Separate from app/core/security.py, which handles admin-API-key auth and
+rate limiting -- unrelated concerns (a machine-to-machine secret vs. a
+human user's own credentials).
+"""
+
+from __future__ import annotations
+
+import uuid
+from datetime import UTC, datetime, timedelta
+
+import jwt
+from argon2 import PasswordHasher
+from argon2.exceptions import VerifyMismatchError
+
+from app.core.config import get_settings
+
+_hasher = PasswordHasher()
+_JWT_ALGORITHM = "HS256"
+ACCESS_TOKEN_TTL = timedelta(hours=24)
+
+
+class InvalidTokenError(Exception):
+    """Raised for any access token that's missing, malformed, expired, or
+    signed with a different key -- callers treat all of these identically
+    (401), so this collapses PyJWT's several exception types into one."""
+
+
+def normalize_email(email: str) -> str:
+    """Emails are matched and stored case-insensitively (RFC 5321 technically
+    allows a case-sensitive local part, but no mainstream provider honors
+    that, and forcing lowercase avoids needing a functional unique index)."""
+
+    return email.strip().lower()
+
+
+def hash_password(password: str) -> str:
+    return _hasher.hash(password)
+
+
+def verify_password(password: str, hashed_password: str) -> bool:
+    try:
+        return _hasher.verify(hashed_password, password)
+    except VerifyMismatchError:
+        return False
+
+
+# Computed once at import time, verified against on a login attempt whose
+# email doesn't exist at all -- so rejecting a nonexistent account takes
+# roughly the same time as rejecting a wrong password on a real one.
+# Without this, a login endpoint's response time itself reveals which
+# emails are registered, letting an attacker enumerate accounts without
+# ever guessing a password.
+_DUMMY_HASH = _hasher.hash("not-a-real-password-used-only-for-timing")
+
+
+def burn_time_like_a_password_check() -> None:
+    verify_password("irrelevant", _DUMMY_HASH)
+
+
+def create_access_token(user_id: uuid.UUID) -> str:
+    settings = get_settings()
+    now = datetime.now(UTC)
+    payload = {"sub": str(user_id), "iat": now, "exp": now + ACCESS_TOKEN_TTL}
+    return jwt.encode(payload, settings.AURORA_SECRET_KEY, algorithm=_JWT_ALGORITHM)
+
+
+def decode_access_token(token: str) -> uuid.UUID:
+    settings = get_settings()
+    try:
+        payload = jwt.decode(token, settings.AURORA_SECRET_KEY, algorithms=[_JWT_ALGORITHM])
+        return uuid.UUID(payload["sub"])
+    except (jwt.InvalidTokenError, KeyError, ValueError) as exc:
+        raise InvalidTokenError(str(exc)) from exc
diff --git a/app/core/ids.py b/app/core/ids.py
index b10f32a..122187b 100644
--- a/app/core/ids.py
+++ b/app/core/ids.py
@@ -51,6 +51,7 @@ ENTITY_PREFIXES: dict[str, str] = {
     "alternate_title": "altt",
     "release": "rel",
     "watch_provider": "watch_provider",
+    "user": "user",
 }
 
 
diff --git a/app/main.py b/app/main.py
index 30d5a9a..2523f83 100644
--- a/app/main.py
+++ b/app/main.py
@@ -23,6 +23,7 @@ from starlette.exceptions import HTTPException as StarletteHTTPException
 
 from app.api.v1 import (
     admin,
+    auth,
     collections,
     companies,
     episodes,
@@ -181,6 +182,7 @@ app.include_router(health.router)
 API_V1_PREFIX = "/api/v1"
 app.include_router(health.router, prefix=API_V1_PREFIX)
 app.include_router(search.router, prefix=API_V1_PREFIX)
+app.include_router(auth.router, prefix=API_V1_PREFIX)
 app.include_router(movies.router, prefix=API_V1_PREFIX)
 app.include_router(series.router, prefix=API_V1_PREFIX)
 app.include_router(seasons.router, prefix=API_V1_PREFIX)
diff --git a/app/models/__init__.py b/app/models/__init__.py
index 99fc6bb..fae8d24 100644
--- a/app/models/__init__.py
+++ b/app/models/__init__.py
@@ -33,6 +33,7 @@ from app.models.tv import (
     SeriesProductionCountry,
     SeriesSpokenLanguage,
 )
+from app.models.user import User
 from app.models.video import Video
 from app.models.watch_provider import WatchProvider, WatchProviderOffering
 
@@ -77,4 +78,5 @@ __all__ = [
     "WatchProvider",
     "WatchProviderOffering",
     "TrendingEntry",
+    "User",
 ]
diff --git a/app/models/user.py b/app/models/user.py
new file mode 100644
index 0000000..bd37505
--- /dev/null
+++ b/app/models/user.py
@@ -0,0 +1,24 @@
+"""Registered AMDBS users -- section 17, additive (accounts/ratings/
+watchlist). The first authenticated-user concept in Aurora Core; every
+other entity in this codebase is public, read-only catalog data."""
+
+from __future__ import annotations
+
+from sqlalchemy import Boolean, String
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.models.base import Base, TimestampMixin, UUIDPrimaryKeyMixin
+
+
+class User(Base, UUIDPrimaryKeyMixin, TimestampMixin):
+    __tablename__ = "users"
+
+    # Stored lowercased (see app.core.auth._normalize_email) so lookups and
+    # the unique constraint are case-insensitive without a functional index.
+    email: Mapped[str] = mapped_column(String(320), unique=True, nullable=False, index=True)
+    hashed_password: Mapped[str] = mapped_column(String(255), nullable=False)
+    display_name: Mapped[str | None] = mapped_column(String(100), nullable=True)
+    is_active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+
+
+__all__ = ["User"]
diff --git a/app/repositories/user_repository.py b/app/repositories/user_repository.py
new file mode 100644
index 0000000..c1be396
--- /dev/null
+++ b/app/repositories/user_repository.py
@@ -0,0 +1,29 @@
+"""Data access for User."""
+
+from __future__ import annotations
+
+import uuid
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.user import User
+
+
+async def get_user_by_id(session: AsyncSession, user_id: uuid.UUID) -> User | None:
+    result = await session.execute(select(User).where(User.id == user_id))
+    return result.scalar_one_or_none()
+
+
+async def get_user_by_email(session: AsyncSession, email: str) -> User | None:
+    result = await session.execute(select(User).where(User.email == email))
+    return result.scalar_one_or_none()
+
+
+async def create_user(
+    session: AsyncSession, *, email: str, hashed_password: str, display_name: str | None = None
+) -> User:
+    user = User(email=email, hashed_password=hashed_password, display_name=display_name)
+    session.add(user)
+    await session.flush()
+    return user
diff --git a/app/schemas/auth.py b/app/schemas/auth.py
new file mode 100644
index 0000000..89c952e
--- /dev/null
+++ b/app/schemas/auth.py
@@ -0,0 +1,30 @@
+"""Registration/login request and response schemas."""
+
+from __future__ import annotations
+
+from datetime import datetime
+
+from pydantic import BaseModel, EmailStr, Field
+
+
+class RegisterRequest(BaseModel):
+    email: EmailStr
+    password: str = Field(min_length=8, max_length=128)
+    display_name: str | None = Field(default=None, max_length=100)
+
+
+class LoginRequest(BaseModel):
+    email: EmailStr
+    password: str = Field(min_length=1, max_length=128)
+
+
+class TokenOut(BaseModel):
+    access_token: str
+    token_type: str = "bearer"
+
+
+class UserOut(BaseModel):
+    id: str
+    email: str
+    display_name: str | None = None
+    created_at: datetime
diff --git a/app/services/user_service.py b/app/services/user_service.py
new file mode 100644
index 0000000..da6505b
--- /dev/null
+++ b/app/services/user_service.py
@@ -0,0 +1,53 @@
+"""Registration and login. See app/core/auth.py for hashing/token
+mechanics -- this layer owns the business rules (duplicate email, wrong
+credentials)."""
+
+from __future__ import annotations
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.auth import (
+    burn_time_like_a_password_check,
+    hash_password,
+    normalize_email,
+    verify_password,
+)
+from app.models.user import User
+from app.repositories.user_repository import create_user, get_user_by_email
+
+
+class EmailAlreadyRegisteredError(Exception):
+    pass
+
+
+class InvalidCredentialsError(Exception):
+    pass
+
+
+async def register_user(
+    session: AsyncSession, *, email: str, password: str, display_name: str | None = None
+) -> User:
+    normalized = normalize_email(email)
+    if await get_user_by_email(session, normalized) is not None:
+        raise EmailAlreadyRegisteredError(normalized)
+    return await create_user(
+        session,
+        email=normalized,
+        hashed_password=hash_password(password),
+        display_name=display_name,
+    )
+
+
+async def authenticate_user(session: AsyncSession, *, email: str, password: str) -> User:
+    normalized = normalize_email(email)
+    user = await get_user_by_email(session, normalized)
+    if user is None:
+        # See burn_time_like_a_password_check's docstring: an email that
+        # doesn't exist must fail no faster than a real one with a wrong
+        # password, or response timing alone reveals which emails are
+        # registered.
+        burn_time_like_a_password_check()
+        raise InvalidCredentialsError()
+    if not user.is_active or not verify_password(password, user.hashed_password):
+        raise InvalidCredentialsError()
+    return user
diff --git a/docs/api.md b/docs/api.md
index 49f2b8e..2554639 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -20,6 +20,19 @@ a consistent envelope:
 | GET | `/health` and `/api/v1/health` | Liveness only. |
 | GET | `/ready` and `/api/v1/ready` | Checks PostgreSQL (always) and Redis (if `REDIS_REQUIRED=true`). |
 
+## Accounts
+
+| Method | Path | Body | Notes |
+|---|---|---|---|
+| POST | `/api/v1/auth/register` | `{"email", "password", "display_name"?}` | Creates an account and logs it in — returns an access token immediately, same as `/login`. `password` is 8-128 characters (length only; NIST 800-63B recommends against complexity rules). 409 if the email is already registered (matched case-insensitively). |
+| POST | `/api/v1/auth/login` | `{"email", "password"}` | Returns `{"access_token", "token_type": "bearer"}`. A nonexistent email and a wrong password both return the identical 401 `invalid_credentials` — distinguishing them would let a client enumerate registered emails, including via response timing (see `app/core/auth.py:burn_time_like_a_password_check`). |
+| GET | `/api/v1/auth/me` | — | Requires `Authorization: Bearer <access_token>`. Returns the caller's own `{"id", "email", "display_name", "created_at"}`. |
+
+Access tokens are JWTs signed with `AURORA_SECRET_KEY`, valid for 24 hours,
+with no refresh-token flow yet — a client re-authenticates (logs in again)
+once a token expires. This is the foundation ratings and a watchlist will
+build on next; those aren't live yet.
+
 ## Search
 
 | Method | Path | Notes |
diff --git a/migrations/versions/0004_users.py b/migrations/versions/0004_users.py
new file mode 100644
index 0000000..446e13e
--- /dev/null
+++ b/migrations/versions/0004_users.py
@@ -0,0 +1,50 @@
+"""users
+
+Revision ID: 0004_users
+Revises: 0003_trending
+Create Date: 2026-09-06
+
+Adds the users table (section 17, additive: accounts/ratings/watchlist)
+-- the first authenticated-user concept in Aurora Core.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0004_users"
+down_revision: str | None = "0003_trending"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "users",
+        sa.Column("id", sa.Uuid(), primary_key=True),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=False,
+        ),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=False,
+        ),
+        sa.Column("email", sa.String(320), nullable=False, unique=True),
+        sa.Column("hashed_password", sa.String(255), nullable=False),
+        sa.Column("display_name", sa.String(100), nullable=True),
+        sa.Column("is_active", sa.Boolean(), nullable=False, server_default=sa.true()),
+    )
+    op.create_index("ix_users_email", "users", ["email"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_users_email", table_name="users")
+    op.drop_table("users")
diff --git a/pyproject.toml b/pyproject.toml
index 2566a23..354e042 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,6 +25,9 @@ dependencies = [
     "python-dotenv>=1.0.1",
     "tenacity>=9.0.0",
     "prometheus-client>=0.20.0",
+    "argon2-cffi>=23.1.0",
+    "pyjwt>=2.9.0",
+    "email-validator>=2.2.0",
 ]
 
 [project.optional-dependencies]
diff --git a/tests/integration/test_auth_api.py b/tests/integration/test_auth_api.py
new file mode 100644
index 0000000..a4dedb3
--- /dev/null
+++ b/tests/integration/test_auth_api.py
@@ -0,0 +1,146 @@
+"""Integration tests for registration/login (section 17, additive) --
+the first authenticated-user flow in Aurora Core. Exercised at the HTTP
+layer (register -> login -> /me with the returned bearer token) rather
+than just the service layer, since that's the actual contract a frontend
+integrates against."""
+
+from __future__ import annotations
+
+import pytest
+from httpx import AsyncClient
+from sqlalchemy.ext.asyncio import AsyncSession
+
+
+@pytest.mark.asyncio
+async def test_register_returns_a_usable_access_token(client: AsyncClient, db_session: AsyncSession):
+    response = await client.post(
+        "/api/v1/auth/register",
+        json={"email": "neo@zion.net", "password": "wake-up-neo", "display_name": "Neo"},
+    )
+    assert response.status_code == 201
+    token = response.json()["access_token"]
+    assert response.json()["token_type"] == "bearer"
+
+    me = await client.get("/api/v1/auth/me", headers={"Authorization": f"Bearer {token}"})
+    assert me.status_code == 200
+    body = me.json()
+    assert body["email"] == "neo@zion.net"
+    assert body["display_name"] == "Neo"
+    assert body["id"].startswith("aur_user_")
+
+
+@pytest.mark.asyncio
+async def test_register_normalizes_email_case(client: AsyncClient, db_session: AsyncSession):
+    response = await client.post(
+        "/api/v1/auth/register",
+        json={"email": "  Trinity@Zion.NET  ", "password": "follow-the-white-rabbit"},
+    )
+    assert response.status_code == 201
+    token = response.json()["access_token"]
+
+    me = await client.get("/api/v1/auth/me", headers={"Authorization": f"Bearer {token}"})
+    assert me.json()["email"] == "trinity@zion.net"
+
+
+@pytest.mark.asyncio
+async def test_register_rejects_duplicate_email(client: AsyncClient, db_session: AsyncSession):
+    await client.post(
+        "/api/v1/auth/register", json={"email": "morpheus@zion.net", "password": "red-pill-please"}
+    )
+    response = await client.post(
+        "/api/v1/auth/register",
+        json={"email": "morpheus@zion.net", "password": "a-different-password"},
+    )
+    assert response.status_code == 409
+    assert response.json()["error"]["code"] == "email_already_registered"
+
+
+@pytest.mark.asyncio
+async def test_register_rejects_duplicate_email_case_insensitively(
+    client: AsyncClient, db_session: AsyncSession
+):
+    await client.post(
+        "/api/v1/auth/register", json={"email": "cypher@zion.net", "password": "i-want-steak"}
+    )
+    response = await client.post(
+        "/api/v1/auth/register", json={"email": "CYPHER@ZION.NET", "password": "something-else"}
+    )
+    assert response.status_code == 409
+
+
+@pytest.mark.asyncio
+async def test_register_rejects_short_password(client: AsyncClient, db_session: AsyncSession):
+    response = await client.post(
+        "/api/v1/auth/register", json={"email": "short@zion.net", "password": "short"}
+    )
+    assert response.status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_register_rejects_malformed_email(client: AsyncClient, db_session: AsyncSession):
+    response = await client.post(
+        "/api/v1/auth/register", json={"email": "not-an-email", "password": "whatever-password"}
+    )
+    assert response.status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_login_succeeds_with_correct_credentials(client: AsyncClient, db_session: AsyncSession):
+    await client.post(
+        "/api/v1/auth/register", json={"email": "tank@zion.net", "password": "operator-standing-by"}
+    )
+    response = await client.post(
+        "/api/v1/auth/login", json={"email": "tank@zion.net", "password": "operator-standing-by"}
+    )
+    assert response.status_code == 200
+    assert "access_token" in response.json()
+
+
+@pytest.mark.asyncio
+async def test_login_rejects_wrong_password(client: AsyncClient, db_session: AsyncSession):
+    await client.post(
+        "/api/v1/auth/register", json={"email": "dozer@zion.net", "password": "the-real-password"}
+    )
+    response = await client.post(
+        "/api/v1/auth/login", json={"email": "dozer@zion.net", "password": "wrong-password-here"}
+    )
+    assert response.status_code == 401
+    assert response.json()["error"]["code"] == "invalid_credentials"
+
+
+@pytest.mark.asyncio
+async def test_login_rejects_unknown_email_with_the_same_error_as_wrong_password(
+    client: AsyncClient, db_session: AsyncSession
+):
+    # Same status code and error code as a wrong password -- see
+    # app/services/user_service.py:authenticate_user. Distinguishing "no
+    # such account" from "wrong password" would let a client enumerate
+    # registered emails.
+    response = await client.post(
+        "/api/v1/auth/login", json={"email": "nobody@zion.net", "password": "does-not-matter"}
+    )
+    assert response.status_code == 401
+    assert response.json()["error"]["code"] == "invalid_credentials"
+
+
+@pytest.mark.asyncio
+async def test_me_rejects_missing_token(client: AsyncClient):
+    response = await client.get("/api/v1/auth/me")
+    assert response.status_code == 401
+
+
+@pytest.mark.asyncio
+async def test_me_rejects_garbage_token(client: AsyncClient):
+    response = await client.get(
+        "/api/v1/auth/me", headers={"Authorization": "Bearer not-a-real-token"}
+    )
+    assert response.status_code == 401
+
+
+@pytest.mark.asyncio
+async def test_me_rejects_a_token_for_a_different_secret(client: AsyncClient):
+    import jwt
+
+    forged = jwt.encode({"sub": "00000000-0000-0000-0000-000000000000"}, "wrong-secret", algorithm="HS256")
+    response = await client.get("/api/v1/auth/me", headers={"Authorization": f"Bearer {forged}"})
+    assert response.status_code == 401
diff --git a/tests/unit/test_auth.py b/tests/unit/test_auth.py
new file mode 100644
index 0000000..0c159da
--- /dev/null
+++ b/tests/unit/test_auth.py
@@ -0,0 +1,96 @@
+"""Unit tests for app/core/auth.py -- pure functions, no DB needed. Written
+after a real bug (watch_provider never registered as an Aurora ID entity
+type) shipped unnoticed because every test touching that path skips
+locally without Postgres -- this module's logic is exercised for real
+here rather than only through integration tests that might not run."""
+
+from __future__ import annotations
+
+import uuid
+
+import pytest
+
+from app.core.auth import (
+    InvalidTokenError,
+    burn_time_like_a_password_check,
+    create_access_token,
+    decode_access_token,
+    hash_password,
+    normalize_email,
+    verify_password,
+)
+
+
+def test_hash_password_round_trips():
+    hashed = hash_password("correct horse battery staple")
+    assert verify_password("correct horse battery staple", hashed) is True
+
+
+def test_verify_password_rejects_wrong_password():
+    hashed = hash_password("correct horse battery staple")
+    assert verify_password("wrong password", hashed) is False
+
+
+def test_hash_password_is_salted():
+    # Same input, different output each time -- otherwise two users with
+    # the same password would have identical hashed_password rows,
+    # trivially revealing the match to anyone with DB access.
+    assert hash_password("same password") != hash_password("same password")
+
+
+def test_normalize_email_lowercases_and_strips():
+    assert normalize_email("  User@Example.COM  ") == "user@example.com"
+
+
+def test_access_token_round_trips():
+    user_id = uuid.uuid4()
+    token = create_access_token(user_id)
+    assert decode_access_token(token) == user_id
+
+
+def test_decode_rejects_garbage_token():
+    with pytest.raises(InvalidTokenError):
+        decode_access_token("not.a.valid.token")
+
+
+def test_decode_rejects_token_signed_with_a_different_key(monkeypatch):
+    import jwt
+
+    from app.core import auth as auth_module
+
+    forged = jwt.encode({"sub": str(uuid.uuid4())}, "a-different-secret", algorithm="HS256")
+    with pytest.raises(InvalidTokenError):
+        auth_module.decode_access_token(forged)
+
+
+def test_decode_rejects_expired_token():
+    from datetime import UTC, datetime, timedelta
+
+    import jwt
+
+    from app.core import auth as auth_module
+    from app.core.config import get_settings
+
+    expired_payload = {
+        "sub": str(uuid.uuid4()),
+        "iat": datetime.now(UTC) - timedelta(hours=48),
+        "exp": datetime.now(UTC) - timedelta(hours=24),
+    }
+    token = jwt.encode(expired_payload, get_settings().AURORA_SECRET_KEY, algorithm="HS256")
+    with pytest.raises(InvalidTokenError):
+        auth_module.decode_access_token(token)
+
+
+def test_decode_rejects_token_missing_subject():
+    import jwt
+
+    from app.core import auth as auth_module
+    from app.core.config import get_settings
+
+    token = jwt.encode({"nope": "no sub claim"}, get_settings().AURORA_SECRET_KEY, algorithm="HS256")
+    with pytest.raises(InvalidTokenError):
+        auth_module.decode_access_token(token)
+
+
+def test_burn_time_like_a_password_check_does_not_raise():
+    burn_time_like_a_password_check()