check-if-email-exists

Check if an email address exists without sending any email.
Comes with a ⚙️ HTTP backend.

👉 Live Demo: https://reacher.email

This is open-source, but I also offer a SaaS solution that has check-if-email-exists packaged in a nice friendly web interface. If you are interested, find out more at No2Bounce.com. If you have any questions, you can contact me at [email protected].

Get Started

3 non-SaaS ways to get started with check-if-email-exists.

1. ⚙️ HTTP backend using Docker (popular method 🥇) [Full docs]

This option allows you to run a HTTP backend using Docker 🐳, on a cloud instance or your own server. Please note that outbound port 25 must be open.

docker run -p 8080:8080 reacherhq/backend:latest

Then send a POST http://localhost:8080/v0/check_email request with the following body:

{
    "to_email": "[email protected]",
    "proxy": {                        // (optional) SOCK5 proxy to run the verification through, default is empty
        "host": "my-proxy.io",
        "port": 1080,
        "username": "me",             // (optional) Proxy username
        "password": "pass"            // (optional) Proxy password
    }
}

Note regarding proxy servers It is possible to operate Reacher with your own IP addresses. But if you wish to process more than very small volumes you will need SMTP proxy servers. For SMTP proxy servers please use proxy25.com

2. Download the CLI [Full docs]

Note: The CLI binary doesn't connect to any backend, it checks the email directly from your computer.

Head to the releases page and download the binary for your platform.

> $ check_if_email_exists --help
check_if_email_exists 0.9.1
Check if an email address exists without sending an email.

USAGE:
    check_if_email_exists [FLAGS] [OPTIONS] [TO_EMAIL]

Check out the dedicated README.md for all options and flags.

3. Programmatic Usage [Full docs]

In your own Rust project, you can add check-if-email-exists in your Cargo.toml:

[dependencies]
check-if-email-exists = "0.9"

And use it in your code as follows:

use check_if_email_exists::{check_email, CheckEmailInput, CheckEmailInputProxy};

async fn check() {
    // Let's say we want to test the deliverability of [email protected].
    let mut input = CheckEmailInput::new(vec!["[email protected]".into()]);

    // Verify this email, using async/await syntax.
    let result = check_email(&input).await;

    // `result` is a `Vec<CheckEmailOutput>`, where the CheckEmailOutput
    // struct contains all information about our email.
    println!("{:?}", result);
}

The reference docs are hosted on docs.rs.

✈️ JSON Output

The output will be a JSON with the below format, the fields should be self-explanatory. For [email protected] (note that it is disabled by Gmail), here's the exact output:

{
	"input": "[email protected]",
	"is_reachable": "invalid",
	"misc": {
		"is_disposable": false,
		"is_role_account": false,
		"is_b2c": true
	},
	"mx": {
		"accepts_mail": true,
		"records": [
			"alt3.gmail-smtp-in.l.google.com.",
			"gmail-smtp-in.l.google.com.",
			"alt1.gmail-smtp-in.l.google.com.",
			"alt4.gmail-smtp-in.l.google.com.",
			"alt2.gmail-smtp-in.l.google.com."
		]
	},
	"smtp": {
		"can_connect_smtp": true,
		"has_full_inbox": false,
		"is_catch_all": false,
		"is_deliverable": false,
		"is_disabled": true
	},
	"syntax": {
		"domain": "gmail.com",
		"is_valid_syntax": true,
		"username": "someone",
		"suggestion": null
	}
}

What Does This Tool Check?

Included?	Feature	Description	JSON field
✅	Email reachability	How confident are we in sending an email to this address? Can be one of safe, risky, invalid or unknown.	is_reachable
✅	Syntax validation	Is the address syntactically valid?	syntax.is_valid_syntax
✅	DNS records validation	Does the domain of the email address have valid MX DNS records?	mx.accepts_mail
✅	Disposable email address (DEA) validation	Is the address provided by a known disposable email address provider?	misc.is_disposable
✅	SMTP server validation	Can the mail exchanger of the email address domain be contacted successfully?	smtp.can_connect_smtp
✅	Email deliverability	Is an email sent to this address deliverable?	smtp.is_deliverable
✅	Mailbox disabled	Has this email address been disabled by the email provider?	smtp.is_disabled
✅	Full inbox	Is the inbox of this mailbox full?	smtp.has_full_inbox
✅	Catch-all address	Is this email address a catch-all address?	smtp.is_catch_all
✅	Role account validation	Is the email address a well-known role account?	misc.is_role_account
✅	Gravatar Url	The url of the Gravatar email address profile picture	misc.gravatar_url
✅	Have I Been Pwned?	Has this email been compromised in a data breach?	misc.haveibeenpwned
🔜	Free email provider check	Is the email address bound to a known free email provider?	Issue #89
🔜	Syntax validation, provider-specific	According to the syntactic rules of the target mail provider, is the address syntactically valid?	Issue #90
🔜	Honeypot detection	Does email address under test hide a honeypot?	Issue #91

🤔 Why?

Many online services (https://hunter.io, https://verify-email.org, https://email-checker.net) offer this service for a paid fee. Here is an open-source alternative to those tools.

License

check-if-email-exists's source code is provided under the MIT License.