WhoisJSON Editorial

Domain Intelligence Blog

Actionable guides on WHOIS, RDAP, DNS, SSL, and domain monitoring for developers and security teams.

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Domainr / Fastly Alternative for Domain Availability Checks

Compare Fastly Domain Research API and WhoisJSON for domain availability checks. Fastly is broader for search and suggestions; WhoisJSON is cheaper for straightforward availability workloads.

Domain Portfolio Management API: Monitor Expiry, DNS, SSL and Availability

Build a domain portfolio management workflow with WHOIS, DNS, SSL, availability and monitoring APIs. Replace spreadsheets with automated expiry checks, DNS inventory, certificate audits and change alerts.

DMARC Lookup API: Check Domain Email Security Policy in JSON

Use a DMARC lookup API to check domain email authentication policy in JSON, interpret p=none, quarantine and reject, and audit MX, SPF TXT, BIMI, MTA-STS and TLS-RPT records.

SecurityTrails Alternative: WHOIS, DNS, SSL and Subdomain API

Compare SecurityTrails vs WhoisJSON honestly: pricing, current and historical DNS, WHOIS, subdomains, SSL certificates, monitoring, reverse search, and when each domain intelligence API is the better fit.

CAA Record API: Check Certificate Authority Authorization Records in JSON

Use a CAA record lookup API to check Certificate Authority Authorization records in JSON, verify approved CAs, and audit certificate issuance policy across domains.

Email Domain Reputation API: Detect Signup Fraud with WHOIS and DNS

Score an email domain at signup with WHOIS/RDAP age, MX records, SPF, DMARC, EPP status and registrar signals. A practical guide for SaaS onboarding and trial-abuse prevention.

Vendor Domain Security Audit: WHOIS, DNS, SSL and Email Security Checklist

Audit a SaaS vendor or third-party provider before onboarding with WHOIS, RDAP, DNS, email security, SSL, subdomains, monitoring and a simple risk score.

WHOIS API Rate Limits: How to Handle 429 Errors and Retries

Learn how to handle WHOIS API rate limits, HTTP 429 errors, retries, timeouts and backoff strategies in production, with Python and Node.js examples.

Best Domain Availability APIs for Developers in 2026

Need a domain availability API with clean JSON and a free tier? Compare WhoisJSON, WhoisXML, Domainr and Namecheap for bulk checks, pricing and dev UX.

2026-05-11

10 min read

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