This is reg.i2p registry service.

Info:
Service is Up. Hosts check is done every hour.
Supported commands:

• adding of hosts for 2LD domains (example.i2p)
• adding subdomains (addsubdomain)
• adding/changing destination (adddest, changedest) - destination is replaced with the new one, old destination is purged

Subscription:
For addressbook subscription use /hosts.txt file.
The link returns basic addressbook upon initial request or request with no If-Match-None header.
Following requests will return full alive hosts list.

Static links to lists:
Lists are updated every 4 hours.

• Basic list: /export/hosts-basic.txt - contains short list of alive popular services
• Alive list: /export/hosts.txt
• Whole list: /export/hosts-all.txt

Rules:
Although there are no specific rules for domain registration, we do have the policy on dead domain records.
Your domain will become open for registration again if it is dead for:

• 3 days if registered less than 7 days ago
• 30 days if registered more than 7 days ago

Approval:
Your domain will generally be approved within 24 hour(s). However, your domain must be alive within the last 3 hour(s) before the approval is due.

External subscriptions:
Our service fetches external subscription updates daily. List of external services:

• identiguy.i2p
• stats.i2p