diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..277a514
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,30 @@
+.PHONY: check lint format fix test typecheck clean
+
+lint:
+	uv run ruff check .
+
+format:
+	uv run ruff format .
+
+fix:
+	uv run ruff check . --fix
+	uv run ruff format .
+
+typecheck:
+	uv run mypy .
+
+test:
+	uv run pytest -v
+
+check:
+	uv run ruff check .
+	uv run ruff format --check .
+	uv run mypy .
+	uv run pytest -v
+
+clean:
+	find . -type d -name "__pycache__" -exec rm -rf {} +
+	find . -type d -name ".pytest_cache" -exec rm -rf {} +
+	find . -type d -name ".ruff_cache" -exec rm -rf {} +
+	find . -type d -name ".mypy_cache" -exec rm -rf {} +
+	find . -name "*.pyc" -delete
diff --git a/pyproject.toml b/pyproject.toml
index 029f156..b7d9ae2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,6 +6,7 @@ readme = "README.md"
 requires-python = ">=3.12"
 
 dependencies = [
+    "email-validator>=2.3.0",
     "pydantic>=2.13.4",
     "pytest>=9.1.1",
 ]
diff --git a/python_fundamentals/exercises/day13_email_validation.py b/python_fundamentals/exercises/day13_email_validation.py
new file mode 100644
index 0000000..eb8f139
--- /dev/null
+++ b/python_fundamentals/exercises/day13_email_validation.py
@@ -0,0 +1,119 @@
+#!/usr/bin/env python3.12
+# file_name: day13_email_validation.py
+# branch: day13_pydantic_advance
+
+from pydantic import (
+    BaseModel,
+    EmailStr,
+    Field,
+    ValidationError,
+    field_validator,
+)
+
+
+class Employee(BaseModel):
+    """Represents an employee within the organization."""
+
+    name: str = Field(
+        min_length=3,
+        max_length=20,
+    )
+    email: EmailStr
+    salary: float = Field(gt=0)
+
+    @field_validator("name")
+    @classmethod
+    def normalize_and_validate_name(cls, value: str) -> str:
+        """
+        Normalize and validate an employee name.
+
+        Rules:
+        - Remove leading/trailing whitespace.
+        - Convert to Title Case.
+        - Name must contain at least 3 characters.
+        - Name must contain alphabetic characters only.
+        """
+
+        value = value.strip().title()
+
+        if len(value) < 3:
+            raise ValueError("Name must contain at least 3 characters.")
+
+        if not value.replace(" ", "").isalpha():
+            raise ValueError("Name must contain alphabetic characters only.")
+
+        return value
+
+
+def print_separator() -> None:
+    print("-" * 60)
+
+
+if __name__ == "__main__":
+    # ---------------------------------------------------------
+    # Valid Employee
+    # ---------------------------------------------------------
+
+    try:
+        valid_employee = Employee(
+            name="   tejas dixit   ",
+            email="tejasdixit17@zohomail.in",
+            salary=25_000.99,
+        )
+
+        print("Valid Employee")
+        print(valid_employee.model_dump())
+
+    except ValidationError as error:
+        print(error)
+
+    print_separator()
+
+    # ---------------------------------------------------------
+    # Invalid Email
+    # ---------------------------------------------------------
+
+    try:
+        invalid_employee_1: Employee = Employee(
+            name="Vignesh Gawali",
+            email="invalid-email",
+            salary=30_000,
+        )
+
+    except ValidationError as error:
+        print("Invalid Email")
+        print(error)
+
+    print_separator()
+
+    # ---------------------------------------------------------
+    # Invalid Name (Contains Digits)
+    # ---------------------------------------------------------
+
+    try:
+        invalid_employee_2: Employee = Employee(
+            name="Tejas123",
+            email="tejas@example.com",
+            salary=30_000,
+        )
+
+    except ValidationError as error:
+        print("Invalid Name")
+        print(error)
+
+    print_separator()
+
+    # ---------------------------------------------------------
+    # Invalid Salary
+    # ---------------------------------------------------------
+
+    try:
+        invalid_employee_3: Employee = Employee(
+            name="Rahul Sharma",
+            email="rahul@example.com",
+            salary=-5_000,
+        )
+
+    except ValidationError as error:
+        print("Invalid Salary")
+        print(error)
diff --git a/python_fundamentals/exercises/inventory.py b/python_fundamentals/exercises/inventory.py
index cf2fafe..23a01f6 100644
--- a/python_fundamentals/exercises/inventory.py
+++ b/python_fundamentals/exercises/inventory.py
@@ -58,7 +58,7 @@ def validate_product(product: Product) -> None:
     if not product.name.strip():
         raise ValueError("Product name is required.")
 
-    if not isinstance(product.price, (int, float)):
+    if not isinstance(product.price, (float)):
         raise TypeError("Price must be numeric.")
 
     if product.price <= 0:
diff --git a/python_fundamentals/notes/day13-email-str-and-field-validator.md b/python_fundamentals/notes/day13-email-str-and-field-validator.md
new file mode 100644
index 0000000..2cdbd14
--- /dev/null
+++ b/python_fundamentals/notes/day13-email-str-and-field-validator.md
@@ -0,0 +1,291 @@
+
+# Day 13 — Advanced Pydantic: EmailStr & `field_validator`
+
+## Learning Objectives
+
+By the end of this lesson I learned:
+
+* How to use specialized Pydantic types.
+* Why `EmailStr` is better than `str` for email fields.
+* How to write custom validation using `@field_validator`.
+* How to normalize input before validation.
+* How to keep business validation inside the model.
+* How to test Pydantic validation using `pytest`.
+
+---
+
+# Why Pydantic?
+
+Python type hints provide static information:
+
+```python
+email: str
+```
+
+This only tells Python that the field is a string.
+
+Pydantic adds **runtime validation**.
+
+```python
+email: EmailStr
+```
+
+Now the field must contain a valid email address.
+
+---
+
+# Specialized Types
+
+Instead of using primitive types everywhere, Pydantic provides semantic types.
+
+Example:
+
+```python
+from pydantic import EmailStr
+
+email: EmailStr
+```
+
+Benefits:
+
+* Validates email addresses.
+* Produces meaningful validation errors.
+* Makes the model self-documenting.
+
+---
+
+# `Field()`
+
+`Field()` is used to declare validation rules.
+
+Example:
+
+```python
+name: str = Field(
+    min_length=3,
+    max_length=20,
+)
+
+salary: float = Field(gt=0)
+```
+
+Supported validations include:
+
+* `min_length`
+* `max_length`
+* `gt`
+* `ge`
+* `lt`
+* `le`
+* `default`
+* `description`
+
+---
+
+# `field_validator`
+
+`field_validator` allows custom validation that cannot be expressed using `Field()`.
+
+Example:
+
+```python
+@field_validator("name")
+@classmethod
+def normalize_and_validate_name(
+    cls,
+    value: str,
+) -> str:
+    ...
+```
+
+A validator can:
+
+* Validate values.
+* Normalize values.
+* Transform values.
+
+---
+
+# Validation Pipeline
+
+When creating a model, validation occurs in this order:
+
+```text
+Input
+    │
+    ▼
+Type Conversion
+    │
+    ▼
+Field()
+    │
+    ▼
+field_validator()
+    │
+    ▼
+Model Created
+```
+
+Understanding this order helps explain why validators receive values that have already been converted to the declared type.
+
+---
+
+# Normalization Before Validation
+
+A common pattern is:
+
+```python
+value = value.strip()
+value = value.title()
+```
+
+Then validate:
+
+```python
+if len(value) < 3:
+    raise ValueError(...)
+```
+
+Finally:
+
+```python
+return value
+```
+
+Recommended order:
+
+```text
+Normalize
+    ↓
+Validate
+    ↓
+Return
+```
+
+---
+
+# Returning the Value
+
+Every validator **must** return the final value.
+
+Example:
+
+```python
+return value
+```
+
+If the value is not returned, the model has nothing to store.
+
+---
+
+# Raising Errors
+
+Inside a validator:
+
+```python
+raise ValueError(...)
+```
+
+Outside the model:
+
+```python
+ValidationError
+```
+
+Pydantic automatically converts `ValueError` into `ValidationError`.
+
+---
+
+# Keeping Validation Inside the Model
+
+Instead of:
+
+```python
+employee = Employee(...)
+
+if employee.salary < 0:
+    ...
+```
+
+Prefer:
+
+```python
+class Employee(BaseModel):
+    ...
+```
+
+The model should enforce its own business rules.
+
+---
+
+# Testing Validation
+
+Validation should be tested using `pytest`.
+
+Example:
+
+```python
+def test_invalid_email() -> None:
+    with pytest.raises(ValidationError):
+        Employee(
+            name="Tejas Dixit",
+            email="invalid-email",
+            salary=25_000,
+        )
+```
+
+Testing validation rules is more reliable than checking printed output.
+
+---
+
+# Best Practices
+
+✔ Use semantic types (`EmailStr`) instead of plain strings.
+
+✔ Keep validation close to the data.
+
+✔ Normalize input before validating.
+
+✔ Return the validated value from every validator.
+
+✔ Raise `ValueError` inside validators.
+
+✔ Test validation using `pytest`.
+
+---
+
+# Concepts Learned
+
+* `BaseModel`
+* `EmailStr`
+* `Field`
+* `field_validator`
+* `ValidationError`
+* `model_dump()`
+
+---
+
+# Key Takeaways
+
+* Type hints describe the expected type.
+* Pydantic validates data at runtime.
+* `Field()` handles common validation rules.
+* `field_validator()` handles custom business rules.
+* Models should protect their own invariants.
+* Validation belongs inside the model, not throughout the application.
+
+---
+
+# Summary
+
+Today I learned how to build self-validating models using Pydantic.
+
+I can now:
+
+* Create runtime-validated models.
+* Use semantic types like `EmailStr`.
+* Normalize incoming data.
+* Implement custom validation with `field_validator`.
+* Test validation logic using `pytest`.
+
+This completes the foundation required before learning **`model_validator`**, where validation involves relationships between multiple fields.
diff --git a/python_fundamentals/tests/test_day13_email_validation.py b/python_fundamentals/tests/test_day13_email_validation.py
new file mode 100644
index 0000000..502db54
--- /dev/null
+++ b/python_fundamentals/tests/test_day13_email_validation.py
@@ -0,0 +1,13 @@
+import pytest
+from pydantic import ValidationError
+
+from python_fundamentals.exercises.day13_email_validation import Employee
+
+
+def test_invalid_email() -> None:
+    with pytest.raises(ValidationError):
+        _: Employee = Employee(
+            name="tejas Dixit",
+            email="invalid-email",
+            salary=25_000,
+        )
diff --git a/python_fundamentals/tests/test_inventory.py b/python_fundamentals/tests/test_inventory.py
index f3a6637..1d869f4 100644
--- a/python_fundamentals/tests/test_inventory.py
+++ b/python_fundamentals/tests/test_inventory.py
@@ -4,7 +4,7 @@
 
 
 def test_invalid_product() -> None:
-    with pytest.raises(ValueError):
+    with pytest.raises(TypeError):
         validate_product(
             Product(
                 name="laptop",
diff --git a/uv.lock b/uv.lock
index 1b911c0..a0b26e8 100644
--- a/uv.lock
+++ b/uv.lock
@@ -126,6 +126,28 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/02/08/9c41fb51ab5b43eb21674aff13df270e8ba6c4b29c8624e328dc7a9482af/distlib-0.4.3-py2.py3-none-any.whl", hash = "sha256:4b0ce306c966eb73bc3a7b6abad017c556dadd92c44701562cd528ac7fde4d5b", size = 470628, upload-time = "2026-06-12T08:04:50.506Z" },
 ]
 
+[[package]]
+name = "dnspython"
+version = "2.8.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/8c/8b/57666417c0f90f08bcafa776861060426765fdb422eb10212086fb811d26/dnspython-2.8.0.tar.gz", hash = "sha256:181d3c6996452cb1189c4046c61599b84a5a86e099562ffde77d26984ff26d0f", size = 368251, upload-time = "2025-09-07T18:58:00.022Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/ba/5a/18ad964b0086c6e62e2e7500f7edc89e3faa45033c71c1893d34eed2b2de/dnspython-2.8.0-py3-none-any.whl", hash = "sha256:01d9bbc4a2d76bf0db7c1f729812ded6d912bd318d3b1cf81d30c0f845dbf3af", size = 331094, upload-time = "2025-09-07T18:57:58.071Z" },
+]
+
+[[package]]
+name = "email-validator"
+version = "2.3.0"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "dnspython" },
+    { name = "idna" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/f5/22/900cb125c76b7aaa450ce02fd727f452243f2e91a61af068b40adba60ea9/email_validator-2.3.0.tar.gz", hash = "sha256:9fc05c37f2f6cf439ff414f8fc46d917929974a82244c20eb10231ba60c54426", size = 51238, upload-time = "2025-08-26T13:09:06.831Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/de/15/545e2b6cf2e3be84bc1ed85613edd75b8aea69807a71c26f4ca6a9258e82/email_validator-2.3.0-py3-none-any.whl", hash = "sha256:80f13f623413e6b197ae73bb10bf4eb0908faf509ad8362c5edeb0be7fd450b4", size = 35604, upload-time = "2025-08-26T13:09:05.858Z" },
+]
+
 [[package]]
 name = "filelock"
 version = "3.29.4"
@@ -144,6 +166,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/94/84/d9273cd09688070a6523c4aee4663a8538721b2b755c4962aafae0011e72/identify-2.6.19-py2.py3-none-any.whl", hash = "sha256:20e6a87f786f768c092a721ad107fc9df0eb89347be9396cadf3f4abbd1fb78a", size = 99397, upload-time = "2026-04-17T18:39:49.221Z" },
 ]
 
+[[package]]
+name = "idna"
+version = "3.18"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/cd/63/9496c57188a2ee585e0f1db071d75089a11e98aa86eb99d9d7618fc1edce/idna-3.18.tar.gz", hash = "sha256:ffb385a7e039654cef1ab9ef32c6fafe283c0c0467bba1d9029738ce4a14a848", size = 196711, upload-time = "2026-06-02T14:34:07.794Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/1e/5e/d4e9f1a599fb8e573b7b87160658329fbf28d19eac2718f51fc3def3aa5a/idna-3.18-py3-none-any.whl", hash = "sha256:7f952cbe720b688055e3f87de14f5c3e5fdaa8bc3928985c4077ca689de849a2", size = 65455, upload-time = "2026-06-02T14:34:06.319Z" },
+]
+
 [[package]]
 name = "iniconfig"
 version = "2.3.0"
@@ -158,6 +189,7 @@ name = "learning-lab"
 version = "0.1.0"
 source = { virtual = "." }
 dependencies = [
+    { name = "email-validator" },
     { name = "pydantic" },
     { name = "pytest" },
 ]
@@ -172,6 +204,7 @@ dev = [
 
 [package.metadata]
 requires-dist = [
+    { name = "email-validator", specifier = ">=2.3.0" },
     { name = "pydantic", specifier = ">=2.13.4" },
     { name = "pytest", specifier = ">=9.1.1" },
 ]