Day 23 of 100 Days Coding Challenge: Python
Today, I built a Python Email Validator, and this is why I got my inspiration.
A long time ago—back when dinosaurs roamed the earth and PDF forms were considered cutting-edge—I managed to sabotage my own job application by giving them the wrong email address. Not wrong like a typo. Wrong like “here’s someone else’s inbox, enjoy!” The form was printable, fillable, but still very much analog when it came to submitting. I only realized my blunder when I sat waiting for a reply that never came. Cue a long, awkward phone call to the admissions office where I had to prove I was me—without sounding like a scammer. They had to resend the link. I had to verify my identity. It was a whole saga. So today, I’ve decided to write a simple email validator. Nothing too fancy—no AI, no spam filters, just the basic “Is this an actual email address or did your cat walk across your keyboard?” kind of check.
Today’s Motivation / Challenge
Let’s be real: checking whether an email is valid feels like it should be automatic—and these days, it often is. But behind that little red warning that says “please enter a valid email” is a small, mighty piece of logic. Today’s project is about building that logic yourself, understanding how to spot a bad address before it sneaks into your system and causes a customer service meltdown. It’s a nod to every web form you’ve ever cursed at.
Purpose of the Code (Object)
This program checks whether the email address someone typed in looks like a real email. That’s it. No email is actually sent—just a quick format check to catch things like missing “@” symbols or suspiciously dot-less domains. It’s like a bouncer for your inbox: if you don’t look the part, you’re not getting in.
AI Prompt:
Write a simple email validation program in Python using regular expressions. The program should have a function that takes an email address and returns whether it is valid. Include a basic GUI using Tkinter where users can input their email and get immediate feedback.
Functions & Features
- Accepts user input via a graphical interface
- Validates email format using a regular expression
- Provides instant feedback: “Valid” or “Invalid”
- Friendly UI with no command line needed
Requirements / Setup
Python 3.x (Tkinter is included by default)
No pip installs needed!
Minimal Code Sample
import re
def is_valid_email(email):
return re.match(r’^[\w\.-]+@[\w\.-]+\.\w+$’, email)
This function checks if the email follows the basic format: name@domain.extension
Notes / Lessons Learned
I thought this code would be a tangled mess of symbols, but it’s surprisingly short and sweet. Here’s the kicker: when I typed xxxxx@mail.com instead of xxxxx@gmail.com, it still counted as valid. So did hello@whatever.io. But hello@gmail? Nope—no dot, no go. It turns out, this kind of validation only cares about structure. It doesn’t know or care whether the domain actually exists—it just wants to see an “@” followed by some dots in the right places. It’s like someone who judges whether a movie is good based only on the poster.
Optional Ideas for Expansion
- Add a domain blacklist to reject shady or disposable email providers
- Highlight formatting errors as you type (e.g., missing “@” or extra spaces)
- Connect to an email verification API for real-time existence checks