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Modernizing Domain Protocols: REPP as an EPP Alternative

EPP is the standard in the domain industry, widely adopted by registries worldwide. EPP has been in use in .ee registry since its approval in 2004 but has its drawbacks. Built on XML (Extensible Markup Language), it is well-structured, but also verbose and challenging for developers to work with effectively. Modern applications, however, predominantly use REST architecture (REpresentational State Transfer), which is simpler, more flexible, and efficient.

Not many developers today are familiar with XML-based APIs. Moreover, EPP has unique characteristics. It defines three distinct operations for object modification: Update, Transfer, and Renew. Of these, Transfer (to change object ownership) and Renew (to extend validity) are specific to EPP. When attempting to integrate third-party tools, such as Papertrail for managing logs or object versions, these extra operations often create issues. These operations are typically categorized as Update operations., requiring custom solutions for accurate data management.

In my experience, although XML is an open standard like EPP, it is difficult to manage, unfamiliar to most developers, and poorly suited for cloud-based and web applications., and comes with a steep learning curve.

Our RESTful alternative to EPP, known as REPP or RPP, has received a warm reception among registrars. Around 10% of queries now flow through REPP, excluding session-specific EPP queries such as login, logout, and hello. This demonstrates a clear need for a more modern and user-friendly solution.

Developing REPP has also provided an opportunity to rethink the interface concept entirely. For instance, objects in domain registrations are seldom reused. This raises the question of whether a simpler, single-object model—where all information is linked to the domain—might be more efficient.

At the same time, I don’t foresee EPP disappearing anytime soon. It remains a deeply embedded industry standard. To reduce the costs of maintaining two overlapping interfaces, we plan to develop a proxy mechanism between EPP and REPP. This would translate EPP queries into REST format and REST responses back into EPP. However, this approach is technically complex due to the fundamental differences: EPP is stateful, requiring session management, while REST is stateless.

The interest shown by both registries and registrars in this topic suggests that it might be worth pursuing the standardization of such solutions to save registrars from integrating diverse interfaces.

This idea has already been raised within the IETF by German and Dutch registries, and efforts are underway to gauge interest and refine the problem statement to determine whether a new standard is feasible. If you'd like to show your support for this initiative, visit IETF RPP Working Group.