Check if an email address exists without sending any email.

npm Github Actions Apache-2.0 david-dm Github Sponsor

What is it?

Check if an email address exists without sending any email.

@reacher/api is a thin TypeScript wrapper around the Reacher Email Verification API. Reacher is a 100% open-source SaaS, written in Rust. It's also free for personal use, and the API token in @reacherhq/api is optional, but without it the requests will be rate-limited to 50 per month.


Install the package:

yarn add @reacherhq/api # Or npm install @reacherhq/api

There are two ways to use the library: by sending single API requests, or by using batch verification.

1. Single Email Verification

import { checkSingle } from '@reacherhq/api';

    { to_email: '[email protected]' },
        apiToken: '<YOUR_TOKEN>', // Optional, rate-limited if not provided.
).then(console.log); // Output will be the JSON described in the "JSON Output" section below.

2. Batch Email Verification

import { batchQueue } from '@reacherhq/api';

// Create a queue for email verifications.
const q = batchQueue({
    // Optional, rate-limited if not provided.
    apiToken: '<YOUR_TOKEN>',
    // Optional, callback to call on each successful verification.
    onSuccessSingle: (result) => {
            `Verified email ${result.input}: the result is ${result.is_reachable}.`

// Push some data into the queue. The email verification will start as soon as
// it's in the queue. The queue has a default concurrency of 100.
q.push({ to_email: '[email protected]' });
q.push({ to_email: '[email protected]' }, { to_email: '[email protected]' });

// Perform some action when the queue is drained.
q.drain(() => {
    console.log('Finished processing all items.');

📚 See Full Documentation

What Does Reacher 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

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
    "mx": {
        "accepts_mail": true,
        "records": [
    "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"

You can also take a look at the OpenAPI v3 specification of this JSON object.


The source code is available under the Apache-2.0 license. See the LICENSE file for more info.

Reacher JS

Check if an email address exists without sending any email.

Reacher JS Info

⭐ Stars 16
🔗 Homepage reacher.email
🔗 Source Code github.com
🕒 Last Update 18 hours ago
🕒 Created 2 years ago
ğŸž Open Issues 10
➗ Star-Issue Ratio 2
ğŸ˜Ž Author reacherhq