Send domain alerts to Discord
Create a Discord channel webhook and connect it to Domain Sentinel so domain expirations, DNS changes and availability alerts arrive as embeds.
Blog
Guides and insights on domain monitoring, WHOIS lookups, and brand protection.
WHOIS & RDAP
Bulk WHOIS lookup: tools, scripts, and API methods
How to query WHOIS or RDAP for dozens or hundreds of domains at once. Web tools, a bash script with rate limiting, and a Python RDAP approach.
ICANN Lookup: check a domain on lookup.icann.org
How to use ICANN Lookup (lookup.icann.org), the official tool for domain registration data: search a domain, read registrar, dates and status, and know its limits.
How to read domain registration data: fields and codes explained
What every WHOIS and RDAP field means: registrant vs registrar vs registry, EPP status codes, expiry dates, nameservers. A practical reference.
Domain registration history: how to find past owners
WHOIS only shows current data. To find past domain owners and registrar transfers, you need third-party archives. Here is where to look and what to check.
WHOIS privacy protection: what it hides and what it does not
WHOIS privacy protection replaces your personal contact data with a proxy service. Here is what it hides, what it cannot hide, and how to enable it.
How to do a WHOIS lookup: 3 methods explained
Three ways to look up WHOIS data for any domain: a web tool, the command line, and a direct RDAP query. Step-by-step with examples.
WHOIS vs RDAP: what changed and why it matters
RDAP is the modern replacement for WHOIS. Same data, but structured JSON over HTTPS instead of raw text on port 43. Here is what changed and why.
What is WHOIS? Domain registration data explained
WHOIS is a public database of domain registration records. Learn what a WHOIS record contains, what you can find, and how it works.
RDAP explained: query rdap.org and registry RDAP servers
What RDAP is and how to query it: rdap.org/domain/example.com, registry endpoints like rdap.verisign.com and rdap.nic.fr, and how to read the JSON reply.
Domain status codes explained: the complete EPP reference
Every domain EPP status code explained: clientTransferProhibited, serverHold, pendingDelete, and more. What each means and what you can do about it.
Monitoring and alerts
Send domain alerts to Slack
Set up a Slack incoming webhook and connect it to Domain Sentinel so expirations, DNS changes and availability alerts land in a channel.
Domain monitoring tools compared: which one for which need
Expiry, DNS, TLS, lookalikes, brand protection: domain monitoring covers four different needs. The tools compared by need, from open source to enterprise.
How domain availability checkers work: cache, WHOIS, and RDAP
Why do two domain checkers give different results? Learn how registrar caches, WHOIS, and RDAP work and what 'available' actually means before you try to register.
Domain watchlist: what it is and how to build an effective one
A domain watchlist monitors your domains automatically for expiration, status changes, and availability. Learn what to include and how to configure it in Domain Sentinel.
Detecting domain registration changes before they cause damage
Learn which RDAP fields change during a domain hijack, how to detect nameserver and registrar changes automatically, and how to respond within hours.
How to monitor competitor domains and detect brand threats
Track competitor domain registrations, nameserver changes, and look-alike domains with RDAP data. A practical guide to competitive domain intelligence.
Get notified when a domain becomes available
Set up a domain availability notification to know when a domain you want becomes free to register. How it works and when to use backorder instead.
How to set up domain monitoring alerts
Learn how to configure automated domain monitoring alerts for expiration, status changes, and availability, and why calendar reminders are not enough.
Expiration and recovery
Expired domain SEO value: what transfers and what doesn't
Backlinks on expired domains don't disappear, but SEO value doesn't transfer automatically. Here's how to evaluate an expired domain and what to realistically expect.
What happens when a domain expires: the complete lifecycle
Expired domains don't disappear immediately. They go through a grace period, a redemption period, and pendingDelete. Here's what each phase means and how long it lasts.
Auto-renew vs manual domain renewal: which is safer?
Auto-renew protects against forgetting, but it fails silently. Here's when each approach makes sense and how to combine both for maximum reliability.
Domain renewal cost: registrar comparison for 2024
How much does it really cost to renew a domain? Compare .com renewal prices across Namecheap, GoDaddy, Cloudflare, Porkbun, and more, with hidden fees.
How to recover an expired domain: grace period to redemption
Domain just expired? You may still be able to get it back. Here's what to do in each phase: grace period, redemption, and pendingDelete.
How to set up domain renewal reminders that actually work
Registrar emails get missed. Learn how to set up reliable domain expiry alerts at 60, 30, 7, and 1 day with an external monitoring tool.
Domain drop list: what it is and how to use one
What a domain drop list is, how it is generated from RDAP data, where to find the best free and paid lists, and how to filter thousands of entries efficiently.
Expired domain auctions: how they work and how to win one
How expired domain auctions work, from the expiry cycle to bidding on GoDaddy and NameJet, plus how to evaluate a domain before placing a bid.
How to track domain expiration across multiple registrars
Centralize domain expiration tracking with RDAP-based alerts. Stop relying on registrar reminder emails and set configurable warnings at 90, 30, and 7 days.
Domain drop catching explained: how it works and when to use it
Domain drop catching lets services register expiring domains in milliseconds. Learn how it works, who it is for, and when a simple availability alert is enough.
Brand protection
UDRP domain dispute: how the process works, costs and timeline
The UDRP lets trademark holders recover bad-faith domains in 45-60 days for under $4,000. Learn the 3 conditions, the process, and realistic success rates.
Defensive domain registration: a strategic guide for brands
Registering domains you do not plan to use is a cost-effective brand protection strategy. Learn which TLDs and variants to cover, and where to stop.
How to spot a phishing domain: signs and detection methods
Phishing domains mimic real URLs to deceive users. Learn to read a suspicious URL, spot homoglyphs and misleading subdomains, and protect your brand.
Which domains should a brand register? A prioritized checklist
Not every domain variation is worth registering. A practical guide to picking the right TLDs and variants for your brand, by budget and risk level.
How lookalike domain detection works: algorithms and methods
Technical guide to detecting lookalike domains: Damerau-Levenshtein distance, homoglyph substitution, and structural pattern analysis with code examples.
Trademark domain protection: rights, conflicts and legal options
A trademark does not automatically give you domain rights. Learn what it covers, common conflicts, and how to reclaim a domain used in bad faith.
What is cybersquatting? Definition, examples and legal recourse
Cybersquatting is the bad-faith registration of a domain matching a brand name. Learn how it works, real cases, and how to fight back.
How to protect your brand with domain monitoring
Learn how to get automatic alerts when someone registers a domain similar to your brand name. Daily RDAP monitoring explained.
Domain extensions
Domain extension meaning: gTLD, ccTLD and sTLD explained
What domain extensions really mean, how they are organized into gTLD, ccTLD, and sTLD categories, and what each type signals to users and search engines.
.com vs .io: which domain should your startup pick?
Honest comparison of .com and .io on SEO, user trust, cost, and registry risk. With real examples and a clear recommendation for tech startups.
Country code TLDs: the complete guide for businesses
Everything you need to know about ccTLDs: eligibility rules by country, local SEO impact, multi-country portfolio strategy, and which restrictions apply.
New gTLDs explained: what they are and which ones matter
A clear guide to new generic top-level domains: how the ICANN program works, which extensions have real adoption, and how to evaluate one before registering.
How to choose the best TLD for your business
Not sure which domain extension to pick? This guide covers every business type, budget, and geography to help you choose the right TLD.
DNS and transfers
The 60-day domain transfer rule: when it applies and how to plan
ICANN blocks transfers for 60 days after registration, a transfer or a registrant change. How to date the window, what it does not block, ccTLD exceptions.
Registry lock vs registrar lock: which domain lock to enable
Transfer lock, registrar lock, registry lock: three locks at three levels of the chain. Who sets each one, what it stops, how it shows in RDAP, which to enable.
How to check SSL certificate expiration and get alerted in time
Read a certificate's expiry date in the browser, with openssl or curl, then put it under daily monitoring with alerts 14, 7, 3 and 1 days before it expires.
DNS monitoring vs uptime monitoring: what each one catches
Uptime monitoring checks if your site responds. DNS monitoring checks if your records are what you set. What each catches, what each misses, and why both.
Subdomain takeover: how it happens and how to catch it
A subdomain takeover starts with a CNAME pointing to a service you no longer use. How dangling records get exploited, how to audit your zone, and prevention.
How to monitor your SPF, DKIM, and DMARC records
SPF, DKIM, and DMARC live in TXT records that break silently: overwrites, key rotations, DNS migrations. Where each one lives and how to get alerted.
How to monitor nameserver changes on your domains
Nameservers control your whole DNS zone, and unplanned changes are rarely good news. How to get alerted when NS records change, on your domains or others.
DNS hijacking: how it works and how to detect it
DNS hijacking redirects your traffic or email by changing DNS answers. The three attack levels, the signals each one leaves, and how to catch it early.
DNS record types explained: A, CNAME, MX, TXT, NS, SOA, SRV
A complete reference for DNS record types. What each one does, when to use it, and real-world examples for A, AAAA, CNAME, MX, TXT, NS, SOA, SRV, and CAA.
DNS propagation: how long it takes and why it varies
DNS propagation takes 1 to 48 hours depending on TTL and resolver caches. Learn what controls the delay, how to check propagation status, and how to speed it up.
How to change nameservers: step-by-step guide for any registrar
Update your domain nameservers at Namecheap, GoDaddy, OVH, or any registrar. Includes Cloudflare migration steps and how to avoid downtime.
Domain transfer lock explained: what it is and how to lift it
clientTransferProhibited means your domain is locked against transfers. Here is what it protects against, how to verify the status, and how to disable it safely.
How to transfer a domain name: a step-by-step guide
Unlock your domain, get the auth code, initiate the transfer. Full walkthrough with ICANN rules, common failures, and timelines explained.
Best domain registrar: an honest comparison
Cloudflare, Namecheap, GoDaddy, Gandi, OVH, compared on real renewal price, security features, and support quality. Pick the right one for your profile.
What is DNS monitoring and when do you need it
DNS monitoring records your DNS setup and alerts you when it changes. What it watches, which incidents it catches, and how to decide if you need it.
Buying and selling domains
Domain parking explained: how it works and what it pays
What domain parking is, how nameserver configuration works, how much it actually pays, and when parking makes sense versus selling or developing.
Domain flipping guide: how it works, what it pays, what can go wrong
How to find undervalued domains, evaluate them before buying, and sell at a profit. Honest look at risks, UDRP disputes, and realistic returns.
Domain valuation: how to find out what your domain is worth
Six factors that determine domain value, how to benchmark with real sales data, and why automated appraisal tools are often unreliable.
Domain portfolio management: a practical guide
How to organize, monitor, and protect a multi-domain portfolio. Audit, registrar consolidation, expiration alerts, and RDAP monitoring explained.
What is a premium domain and is it worth the price?
Premium domains explained: the difference between registry premiums and aftermarket domains, how prices are set, and how to decide if one is worth buying.