EPP Protocol and Domain Management API

What Is EPP?

Extensible Provisioning Protocol is the XML-based API registries use to create, transfer, renew and delete domains. Think of it as the backend language between registrars and registries like Verisign or Nominet.

XML Frame Anatomy

Each command wrapped in root, then , then action-specific stanza (e.g., , , ). Transaction id and client credentials travel in and tags. All communication over TLS 1.3 with mutual certificate auth.

Standard Commands

• domain:check – availability
• domain:create – register
• domain:info – status, dates, contacts
• domain:renew – extend expiry
• domain:transfer – request auth-code transfer
• domain:delete – send to redemption

Code Example (Python)

Send for “example.com”, parse XML response for avail flag. If true, follow with including registrant contact XML chunk and 1-year period. Wrap in try/except to catch 2303 “object exists” or 2200 “authentication error”.

Rate Limits & Throttles

Verisign allows 20 transactions/sec per IP but registrar accreditation agreement caps 1,000 checks/min for load balancing. Burst above limit returns 5202 “Command failed; limit exceeded”.

Contact Objects

Registrant, admin, tech, billing contacts stored separately with contact:cre Data. Each contact gets ROID (Repository Object ID) reused across multiple domains—think foreign-key relationship.

Extensions: RFC 5730-5734

Launch Phase (EPP-Launch) adds tag for sunrise/landrush. DNSSEC extension adds for key material. Price tier extension signals premium names during create.

Error Handling

EPP returns result code 1000 for success, 1001 for success with pending. 2xxx range means client error (bad XML), 5xxx server error (registry down). Log full XML on 5xxx for registrar support tickets.

Registry Differences

.uk uses EPP but requires IPS tag change instead of auth-code. .fr needs “declarant” contact with EU address. Always read registry-specific implementation guide before coding universal module.

Future: JSON/REST

Some new gTLD registries expose JSON gateways, but EPP remains mandatory for .com/.net/.org. Learn XML EPP first; REST wrappers are thin facades over same protocol.