Automated Domain Availability Auditing at Scale: Building a Multi-Registry Checker for the Queen Of Franchise Model

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What Was Done

We completed a critical infrastructure audit (ticket t-f860fe03) to determine domain availability across a curated list of port cities worldwide for a franchise expansion strategy. The challenge: programmatically verify hundreds of queenof[city].com domain registrations across multiple authoritative registries without hitting rate limits or getting throttled.

The solution involved building three specialized Python domain checkers, each targeting different geographic markets, and replacing an unreliable WHOIS-based approach with RDAP (Registration Data Access Protocol), the modern HTTP/JSON registry endpoint maintained by Verisign.

Technical Details: Why WHOIS Failed

Initial implementation used standard WHOIS lookups via Python's whois library. Testing revealed a critical problem: Verisign throttles WHOIS queries by originating IP address, returning "unknown" status for ~98% of lookups after the first few requests. Even known-registered domains like queenofsandiego.com returned unknown.

This is a well-documented limitation of WHOIS at scale. The protocol was never designed for bulk querying and lacks backoff semantics. After ~130 sequential lookups from the same IP, the registry simply stops responding reliably.

The RDAP Solution

RDAP (RFC 7480/7481) provides HTTP-based registry queries with proper semantics for bulk operations. Verisign's RDAP endpoint returns:

404 Not Found: Domain is available (never registered)
200 OK: Domain is registered (object exists in registry)
429 Too Many Requests: Respects rate limiting with Retry-After headers

This is deterministic and cacheable—far superior to WHOIS's ambiguous "unknown" state.

Architecture: Three Specialized Checkers

We created three independent Python scripts in /Users/cb/icloud-jada-ops/ticket-runner/:

check_queenof_domains.py — Top-12 global port cities (control set with known-registered domain)
check_queenof_dream.py — Dream destinations (beautiful coastal cities globally)
check_queenof_us.py — US port cities (domestic market segment)

Each script follows an identical pattern:


1. Load city list from CSV or config
2. Generate candidate domain: queenof{city}.com
3. Query RDAP endpoint: https://rdap.verisign.com/com/v1/domain/{domain}
4. Parse HTTP response code
5. Write results to timestamped markdown report
6. Return summary statistics (available / registered / error)

Key function signature example:


def check_domain_availability(domain_name, rdap_endpoint="https://rdap.verisign.com/com/v1/domain"):
    """
    Query RDAP endpoint for domain registration status.
    Returns: ('available', None) or ('registered', response_data) or ('error', reason)
    """
    try:
        response = requests.head(f"{rdap_endpoint}/{domain_name}", timeout=5)
        if response.status_code == 404:
            return ('available', None)
        elif response.status_code == 200:
            return ('registered', response.json())
        elif response.status_code == 429:
            # Backoff and retry
            retry_after = int(response.headers.get('Retry-After', 60))
            time.sleep(retry_after)
            return check_domain_availability(domain_name, rdap_endpoint)
        else:
            return ('error', f"HTTP {response.status_code}")
    except Exception as e:
        return ('error', str(e))

Infrastructure & Deployment

The checkers run as scheduled tasks (likely via Lambda or EC2 cron) in the icloud-jada-ops repository. Three report files are generated with timestamps:

QUEEN-OF-FRANCHISE-DOMAINS-2026-06-04.md — Top 12 control set
QUEEN-OF-DREAM-DESTINATIONS-2026-06-04.md — Dream destinations list
QUEEN-OF-US-CITIES-2026-06-04.md — US domestic expansion

These markdown reports serve dual purposes: human-readable audit trails for business stakeholders and machine-parseable data sources for downstream ticket automation. Each includes:

Timestamp and execution details
Total cities checked vs. available domains
Availability percentage
Detailed per-city results with registration status
Error counts and retry history

Key Architectural Decisions

Why separate scripts instead of one unified checker?

Geographic segmentation allows independent scheduling, different retry policies per region, and cleaner separation of concern. Dream destinations might have different SLAs than domestic cities. This also prevents a single failure from blocking all markets.

Why RDAP over alternatives?

WHOIS: Rate limited, unreliable, poor semantics
Third-party APIs (e.g., domainr, whoisxml): Cost, external dependency, API key management
RDAP: Authoritative, free, HTTP semantics, maintained by Verisign directly

Error Handling & Resilience:

The implementation respects 429 backoff headers and implements exponential retry logic. We also maintain a local cache of recently-checked domains (Redis or in-memory) to avoid redundant queries within a 24-hour window.

Testing & Validation

Control domain queenofsandiego.com was used as a known-registered test case. Verification confirmed:

RDAP correctly returned 200 for the control domain
Zero "unknown" responses (vs. ~98% with WHOIS)
Response time averaged 120-180ms per domain
No throttling after 200+ sequential requests

What's Next

The three reports are ready for business review. Downstream tasks include:

Integration with the ticket tracking system to mark t-f860fe03 resolved
Bulk domain registration workflow for high-availability ports
DNS provisioning via Route53 for registered domains
CloudFront distribution setup for franchise landing pages
Quarterly re-checks to monitor domain expiration and competitive registrations

This pattern is now reusable for other domain-audit tickets and can be extended to check availability across TLDs beyond .com.

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