Our API is FREE TO USE in exchange for anonymous data sharing. The data is shared exclusively with our parent company, Return Path, so they can build products which improve the entire email ecosystem - anti-phishing, spam prevention, and deliverability tools.

If you prefer to opt-out of data sharing, you can learn more about the cost to opt-out below.

  • Lite API
  • Free
  • Unlimited API calls
  • Unlimited Users
  • 2.0 API
  • Free
  • Unlimited API calls
  • Unlimited Users

Get your free API key

Learn more about the difference between Lite and 2.0



Prefer to opt-out of data share?

If you prefer to opt-out of data sharing, we can arrange this on a per user basis. The cost for opting out is $0.79 per user per month. Users can also opt out individually through this simple form and in such cases there is no charge to you. In fact, we require all developers to explicitly list the opt-out in their privacy policy so all end users are aware they are not required to partake in the anonymous data sharing.

Data sharing opt-out bulk pricing

If you are interested in opting out of data share and want to arrange bulk pricing for your user base, our bulk pricing for data opt-out can be found below.

  • Number of Accounts
  • 1-100 Accounts
  • Up to 2500 Accounts
  • 2500-5k Accounts
  • 5k+ Accounts
  • Price
  • FREE
  • $0.79 per user / month
  • $1,700 / month
  • Enterprise pricing available. Contact us!


Why is the API free?

Don’t worry, we’re not going anywhere! We are able to support the API through our parent company, Return Path. They use anonymous, aggregate data about the email messages your end users receive from commercial senders to create products that improve the entire email ecosystem, including reducing spam and preventing email fraud. This allows us to provide our API services for free in support of startups/entrepreneurs and can continue to accelerate development and innovation.

If you prefer to opt-out of anonymous and aggregated data sharing, we can arrange this on a per user basis. The cost for opting out is $0.79 per user per month. For applications with large user bases, bulk pricing is available. Please contact us at for more information.

We deeply respect consumer privacy and strive to be as transparent as possible. We follow industry-leading practices around data privacy and security like:


  • Return Path is a Participant in the TRUSTe Privacy Seal Program. TRUSTe is the leading global Data Privacy Management (DPM) company and powers trust in the data economy by enabling businesses to safely collect and use customer data across their customer, employee, and vendor channels.
  • All Personally Identifiable Information (PII) is redacted within a tightly controlled data processing environment with limited access.
  • The redaction process removes any PII that can be used on its own or with other information to identify, contact, or locate a single person, or to identify an individual. This includes (but is not limited to) information like email address or combinations, for example, a user's street name and car model, from both the email text and creative.
  • Return Path will only look at email messages from commercial senders.

How does Return Path use email data?

How does Return Path use email data?

Each day, companies around the world send billions of emails to customers and subscribers like you. By using our products, you allow us to combine data about the commercial mail you receive with millions of other email accounts. We then anonymize the information so each person's identity is safe and secure. We use the data to help stop spam and prevent phishing attacks, improving email for everyone. The result is a better inbox, with more of the email you want and less of the email you don't.


  • Return Path employs a full-time Security Operations and Privacy team, managed by a full-time Chief Privacy and Security Officer with over 20 years of experience in cross-border data flows, rules and regulations.
  • All client and consumer data must be encrypted during transit using strong encryption mechanisms.
  • We self-certify compliance with Safe Harbor. U.S.-EU Safe Harbor Framework provides a method for U.S. companies to transfer personal data from the European Union to the United States that is consistent with the requirements of the EU Data Protection Directive.
  • Return Path conducts periodic reviews of our security policies and practices through independent third-party auditing services, including ISO certifications and Statements on Standards for Attestation Engagements No. 16 (SSAE 16) Reporting on Controls at a Service Organization (SOC 2) Audits, as well as internal auditing services and other assessments deemed appropriate. We also audit our systems and software weekly to ensure their security.

Read more in our Privacy FAQ or reach out to us directly at if you have more questions or would like more information.