Introducing the isitdisposable.com blog

Welcome to the isitdisposable.com blog. We built isitdisposable.com to answer one narrow question well: is a given email address disposable, meaning it comes from a throwaway or temporary provider that a person can create for a single signup and abandon minutes later. This blog is where we will write about that problem, the wider world of fraud prevention it sits inside, and what we ship along the way.

What is isitdisposable.com?

isitdisposable.com is a detection service for disposable and throwaway email addresses. It ships two ways to use it: a drop-in JavaScript snippet that a non-technical site owner can paste onto a signup form with no code changes, and a clean Representational State Transfer (REST) Application Programming Interface (API) for developers who want to check addresses from their own backend. Both call the same detection engine, so a marketer and an engineer get the same answer.

Under the hood, detection is Domain Name System (DNS) based only. We look at how a domain resolves and behaves, and we compare it against a maintained list of known disposable providers and patterns. We never attempt Simple Mail Transfer Protocol (SMTP) mailbox probing, meaning we never connect to a mail server to ask whether a specific inbox exists. That approach is slow, unreliable, and can get a sending Internet Protocol (IP) address blocklisted, so we deliberately leave it out. The result is a fast, DNS based check that returns a verdict in milliseconds.

Why does disposable email detection matter?

A throwaway signup rarely represents a real, engaged user. It can inflate signup counts without adding real customers, let one person create many free accounts to dodge a trial limit, or give a spammer a fresh identity for abuse. Filtering disposable addresses at signup keeps a product's user base closer to its real audience and makes downstream metrics, like activation and retention, mean what they are supposed to mean.

At the same time, we are careful about what counts as disposable. A forwarding address, a relay address, or a mainstream public email provider is not the same thing as a throwaway address, and treating them all the same way would block real customers. Our core verdict stays narrow and reliable, and other signals are opt-in, so a business can decide for itself how strict to be.

What will we write about?

Expect three kinds of posts here, matching the categories on this blog:

• Guides: practical explainers on disposable email detection and email verification, written for the person setting up a signup form, not just for engineers.
• Fraud prevention: why throwaway signups hurt products in ways that are easy to miss, and what to do about them.
• Product updates: announcements and release notes as isitdisposable.com adds new features.

How do we treat reliability?

One design choice worth mentioning up front because it shapes everything we build: isitdisposable.com is designed to never break a customer's signup form. If an account runs out of its checking allowance for the period, the service does not start rejecting or erroring out. Instead it returns a safe, non-blocking response and lets the form proceed as if no check had run. We call this a hard stop that fails open, and it means a billing or quota problem on our side can never turn into a broken signup form on a customer's site.

Thank you for reading the first post. We plan to keep this blog practical: real detection guidance, real fraud prevention thinking, and honest notes on what we ship, in that order.