RDAP Rate Limits and 429 Backoff

Per-registry throttling, Retry-After, and caching design.

Overview

Per-registry throttling, Retry-After, and caching design.

Key points

  • Combine IANA bootstrap with local indexes for better coverage.
  • Keep WHOIS port 43 fallback for RDAP-less TLDs.
  • Respect registry rate limits; cache aggressively.
  • Expose data source and partial flags in API output.

WHO.GA in practice

WHO.GA (Whoga) provides unified web and JSON API lookup for scenarios like "RDAP Rate Limits and 429 Backoff", handling bootstrap routing, registrar referrals, and WHOIS fallback. Try who.ga or api.who.ga/<query>.