Overview
The .CO EPP system enforces session and transaction limits to ensure fair access for all Registrars. Understanding these limits helps you architect a stable, compliant EPP client.
Session Limits
- Maximum concurrent sessions: 100 per Registrar account during normal operations.
- Check command limit: 50 objects per single <check> command.
- Other commands: no throughput throttling — the server responds as soon as the command is processed.
Idle Session Timeout
The EPP server will terminate an idle session if no command is received within 300 seconds (5 minutes). To keep a session alive, use the <hello> command before the timeout expires. Use care with pipelining — a pipeline may cause an unexpected timeout if not managed correctly.
Drop-Catching Exception
Domain:create commands that result in a 2302 'object exists' error are subject to a minimum 2-second round-trip time. This is enforced server-side to mitigate the impact of drop-catching on system stability.
Login Rate Limiting
If your EPP login command returns a response indicating rate limiting, your account may be temporarily restricted. Check the response code and back off before retrying.
Fair Use Policy
The Registry reserves the right to further restrict session counts or command throughput for any Registrar engaged in excessive or abusive behaviour. See RES-06: Fair Use Policy for details.
Related Articles
- Fair Use Policy — When the Registry Can Restrict Your Access
- Drop-Catching on .CO — Policies, Limits, and Best Practices
- How to Build Your EPP Client