RDAPLookup

By RDAPLookup Editorial TeamPublished October 1, 2026 · Updated October 24, 2026

ARIN 58: Whois-RWS API targets July 2027, port 43 WHOIS stays available

ARIN's October 23 roadmap keeps July 2027 as a conditional Whois-RWS API retirement target. Advanced RDAP Search will run alongside the existing web interface for at least six months, while port 43 WHOIS remains available.

Update details

Change
Directory services roadmap updated
Announcement date
October 23, 2026
Affected services
Whois-RWS API, Whois-RWS web interface, RWhois, Whois (Port 43)

The American Registry for Internet Numbers has published the next steps for its directory-service transition following community consultation. At ARIN 58 on October 23, 2026, Hollis Kara presented a roadmap that separates the Whois-RWS API, its web interface, organization-operated RWhois and traditional WHOIS on TCP port 43.

The ARIN 58 Day 2 recap and Directory Services presentation expand on the October 21 consultation outcome. For teams migrating IP address and Autonomous System Number lookup tools, the important change is a conditional API target and separate transition conditions for the other services, not a single WHOIS shutdown date.

ARIN already provides RDAP for IP and ASN registration data. This roadmap is not an RDAP launch or an immediate closure of the older services.

Four services, four transition paths

The presentation’s next-steps summary sets out the current plan:

Service Current retirement plan What must happen first
Whois-RWS API July 2027 remains the conditional target. Resolve remaining RDAP parity questions and update documentation. The October 21 outcome also requires necessary training improvements before deprecation.
Whois-RWS web interface Retirement date remains undecided. Complete the Advanced RDAP Search beta, now under development, and run it alongside the existing interface for at least six months to gather feedback and support migration.
RWhois Retirement follows a 365-day countdown. Make the migration tool publicly available. Publication of the tool, not the meeting or announcement date, starts the countdown.
WHOIS on port 43 Remains available, with no retirement date set. Reach community-identified adoption milestones, then hold another consultation on potential retirement.

July 2027 is an API planning target, not a newly confirmed July 1 deadline or a shutdown date for the web interface. ARIN plans eventually to redirect the existing web interface to Advanced RDAP Search, but the beta’s launch and the old interface’s retirement dates are not supplied in these sources. The six-month parallel period is not a countdown from October 23.

For port 43, ARIN reported that 24 of 43 substantive comments opposed retirement or requested a longer transition. It will monitor RDAP adoption in operating-system distributions and commercial products, as well as query traffic, before returning to the community. The published outcome does not specify numerical adoption thresholds or a date for that consultation.

ARIN also commits to direct outreach and education for current users before retiring any service.

API parity: test more-specific networks and reassignments

In slide 9, ARIN described a perceived functional gap around queries for more-specific CIDR blocks: breaking out reassignments within a larger block and walking the network hierarchy. ARIN said Whois-RWS supports this workflow and RDAP does not yet expose it cleanly. Its API plan calls for confirming parity requirements and clarifying the documentation before retirement.

That concern should not be read as a blanket claim that ARIN’s RDAP endpoints cannot return child networks or assignments. ARIN’s current RDAP documentation describes rirSearch1 hierarchy searches. Live checks on October 24, 2026 returned HTTP 200 with application/rdap+json for:

A separate rdap-down/12.0.0.0/8 check returned assignment records with a notice that search results are limited per query. These examples establish working hierarchy queries, not complete parity with every Whois-RWS workflow. The sources do not settle which remaining cases ARIN considers unresolved.

For migration testing, distinguish a lookup of one IP address or prefix from a search for networks beneath a larger block. Compare the records your existing Whois-RWS query returns with the relevant RDAP relation searches. Check immediate children versus deeper descendants, covering records and result-limit notices before assuming a successful response is a complete reassignment inventory.

What lookup-tool maintainers should do now

For IP address and ASN lookups, discover the authoritative RDAP service through the relevant IANA bootstrap registry rather than assuming every resource belongs to ARIN.

Our WHOIS-to-RDAP migration guide covers discovery, response validation, error handling, rate limits and rollout testing. The guides to reading an IP address RDAP response and reading an ASN RDAP response explain the number-resource fields without relying on WHOIS text layouts.

Historical proposal, not current deadlines

The original consultation ran from August 14 to September 14, 2026. It proposed these earliest retirement dates:

Service Originally proposed earliest retirement Original qualification
Whois-RWS API July 1, 2027 After a 180-day customer outreach program.
RWhois January 1, 2028 Dependent on the migration tool, followed by a 365-day sunset.
WHOIS on port 43 January 1, 2029 After a proposed two-year sunset and outreach period.

These dates record the August proposal. The October outcome and ARIN 58 roadmap above are the current planning basis: July 2027 remains conditional for the API, RWhois is tool-triggered, and port 43 requires another consultation.

Sources

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