New Base URL for Reg-RWS

Posted: Wednesday, 19 February 2020

On 16 July and 30 October of 2019, we announced plans to implement changes to our RESTful API. We noted that these changes might impact the way you interface with ARIN Online for sending reassignment information and receiving reports through ARIN’s Registration RESTful Service (Reg-RWS).

These changes consist of:

  1. The base URL will no longer be available for Reg-RWS. You must change your base URL to to interface with ARIN’s Reg-RWS service. The base URL has been in place for seven years as the improved way of interfacing with ARIN via Reg-RWS.
  2. ARIN will no longer be supporting TLS version 1.0 for Reg-RWS’s transport layer because of well-known security issues with this version of the protocol. We will continue to support TLS 1.1 and 1.2. Please make sure your client implementation will support TLS 1.1 or 1.2. Read for further details.

The change to TLS support was completed successfully on 4 February, 2020. On 19 February 2020, we completed the change of the base URL to


Mark Kosters
Chief Technology Officer
American Registry for Internet Numbers (ARIN)