Last update: 15th August 2022.

Reacher API

What is your accuracy rate?

Since we check emails on the spot, in real-time, the accuracy rate is high. Depending on the value of the email's reachability, we guarantee the following accuracies:
  • safe: We guarantee a hard bounce rate lower than 3%. Bounce rates may still happen, because we connect to the email's SMTP server from a different IP address than you, and yours might be blacklisted.
  • invalid: We guarantee with a confidence of 99% that this email is not deliverable.
  • risky: The email address appears to exist, but has quality issues that may result in low engagement or a bounce. We don't recommend sending to these emails, and don't commit on an accuracy rate.
  • unknown: It might happen on rare occasions that the email provider doesn't allow real-time verification of emails. In this case, there's unfortunately nothing Reacher can do. Please let us know if this happens, we're working on finding ways to solve these issues, which in most occasions are solved on a case-by-case basis.

What does is_reachable: "unknown" mean?

In most cases, this error happens on timeout, when port 25 is closed. On some occasions, it might also happen that the email provider doesn't allow real-time verification of emails (for example, Hotmail). In this case, there's unfortunately nothing Reacher can do. Please let us know if this happens, we're working on finding clever ways to work around these issues.

What does is_reachable: "risky" mean?

An email is considered risky when at least one of the following is true:
  • is a disposable email address (DEA),
  • is a role account (e.g. support@ or admin@),
  • is a catch-all address,
  • has full inbox.
In these cases, we don’t guarantee the deliverability of the email address.

How many emails can I verify per month?

Reacher’s email verification monthly limits depends on your subscription:
  • if you use the Free Tier: the limit is 50 email verifications for the past month, on a rolling basis
  • if you use the 10k Emails (SaaS) Plan: the limit is 10000 email verifications per subscription period (1 month), i.e. the counter resets at the beginning of each new period.
  • if you use the Commercial License Plan: the number of verifications is unlimited.

How can I track the number of emails I verified?

For the Free Tier and 10k Emails (SaaS) plans, you can track the number of email verifications you did on Reacher’s dashboard: https://app.reacher.email.
For API usage, you can also check the HTTP response headers after each API call:
  • X-RateLimit-Limit: the maximum number of email verifications per period (50 or 10000).
  • X-RateLimit-Remaining: the number of remaining verifications in the current period.
  • X-RateLimit-Reset: the date at which the counter will reset.
  • Retry-After: the number of seconds before X-RateLimit-Reset.

What are hard bounces?

Hard bounces are email addresses that could not be delivered, for example due to an invalid mailbox. They are treated very seriously by most email service providers.

Do you provider bulk email validation?

Yes! However, it’s only a feature for users on the Commercial License plan who self-host Reacher.
You can learn more at 💪Bulk Email Verification.

How is real-time verification done?

The process is fairly straightforward and outlined in the 4-line telnet script below.
  • Line 1: We first form a connection to the mail server with a basic TCP connection on port 25.
  • Line 2: We then identify ourselves as example.com
  • Line 3: We act as if we were going to send an email, by inputting a mail-from email address of testing@example.com.
  • Line 4: Continuing our fake email process, we set the recipient email with RCPT TO command. This is the email we want to check.
  • Line 5: The remote SMTP server returns a response at this step. Based on the response from the mail server, we are able to conclude the deliverability of the given email address. For example, the server might return 250 2.1.5 OK, which implies a valid inbox. Reacher’s magic comes from the fact that it can parse responses from a wide range of providers.
telnet mail.abccorp.com 25
HELO example.com
MAIL FROM: <testing@example.com>
RCPT TO: <your_email@somedomain.com>
// Parse the response of the `RCPT TO` command.
If you can read code, then the best is to check out Reacher's open-source code at https://github.com/reacherhq/check-if-email-exists.

How to use Reacher with a proxy?

Reacher allows verifying emails using a SOCK5 proxy. Please note that HTTP proxies are not supported, because Reacher performs SMTP checks which happen on a different protocol than HTTP.
To verifying an email using a proxy, simply send an API request with a proxy field:
	"to_email": "someone@gmail.com",
	"proxy": {
		"host": "my.proxy.com",
		"port": 8001,
    "username": "myusername", // Optional
    "password": "mypassword"  // Optional
Please also see the 📖REST API Documentation for more details about the endpoint.

Account, Billing & Security

How secure is my data?

Reacher takes security and privacy seriously. It's simple, we do not store the emails you check, and we do not share your data with any third parties. The email verification is done in real-time, and once it's finished, we clear everything.
If you self-host, no data whatsoever is sent back to Reacher.

Is your service GDPR-compliant?

Yes, our service is based in France, so is fully compliant with the GDPR by law. Please refer to our for more information.

What form of payments do you accept?

Payment can be made by Visa, MasterCard or Amex. Behind the scenes, we use Stripe to process payments.

Self-Hosting & Commercial License

Please see the 🏠Self-Host Guide, and its FAQ section at the bottom, for questions on self-hosting, as well as the dedicated 🎓Reacher Licenses page.

Who is the team behind Reacher?

I'm Amaury, an indie developer based in Paris 🇫🇷. It’s only me behind Reacher. Say hi to me 👋, ✉️ amaury@reacher.email.