How I Built and Deployed a Free Email Validation API with Python and FastAPI

I recently built and deployed my first API — an email validation tool built with Python and FastAPI. Here's how I did it and what I learned along the way. Why Email Validation? Every app that accepts user signups needs email validation. Most developers either roll their own regex (which misses a lot) or pay too much for an enterprise solution. I wanted to build something simple, affordable, and reliable. What It Does The API checks email addresses for: Format — RFC 5322 compliance MX Records — confirms the domain actually receives email Disposable domains — flags throwaway addresses like mailinator.com Typos — catches mistakes like gmial.com and suggests gmail.com Each response includes a 0-100 quality score. The Tech Stack Python — FastAPI for the web framework dnspython — for MX record lookups Railway — for deployment RapidAPI — for distribution and billing Quick Example import requests url = " https://email-validation52.p.rapidapi.com/validate " params = { " email " : " test@gmail.c