nslookup.io is one of the best online implementations of the classic nslookup command. The interface is clean and fast — type a domain, pick a record type, get accurate results instantly. They’ve built on this core with a website-to-IP lookup, dedicated pages for each DNS record type, a learning section explaining DNS concepts, and programmatic pages for popular domains.
It works well for what it does: DNS record lookups. The site earns 135K monthly visitors, 62% of which go to the homepage for nslookup queries and 25% to the website-to-IP converter.
DomainScan started from the same place — solid DNS lookup — and built outward to answer the question that always follows a DNS check: “So my records are there… but is everything actually working correctly?”
What Each Does
nslookup.io
nslookup.io is a focused DNS lookup platform:
- DNS record lookups — A, AAAA, MX, TXT, CNAME, NS, SOA, PTR, SRV, CAA, and more
- Website to IP lookup — resolves any hostname to its IP address(es)
- Reverse IP lookup — hostname from IP via PTR records
- Per-record-type pages —
/txt-lookup/,/mx-lookup/,/cname-lookup/,/soa-lookup/, etc. - Programmatic domain pages —
/domains/google.com/webservers/showing infrastructure for popular domains - DNS propagation checker — checks record status across multiple resolvers
- Learning section —
/learning/dns-record-types/soa/educational articles per record type
The tool is clean, fast, and does its job well. It’s ad-supported with no paid tier.
DomainScan
DomainScan covers DNS lookup as the foundation of a broader domain intelligence platform:
- Full DNS lookup — same record types with health scoring and anomaly detection
- Email authentication — SPF, DKIM, DMARC validation + alignment + 0-100 auth score
- Blacklist check — 50+ major DNSBLs for domain and outbound mail server IP
- SSL/TLS inspector — certificate validity, chain, expiry countdown, cipher analysis
- Domain Trust Score — composite score across DNS, email, SSL, security headers
- DNS propagation — multi-region propagation with TTL analysis
- Prism AI — explains every result in plain English and writes exact fix instructions
- Monitoring — blacklist alerts, DNS change detection, SSL expiry, email auth drift
- White-label reports — branded PDF/HTML for agency use
- API + MCP — programmatic access and AI agent integration
Feature Comparison
| Feature | DomainScan | nslookup.io |
|---|---|---|
| DNS records (A, AAAA, MX, TXT, NS, SOA, CNAME) | ✅ | ✅ |
| PTR / reverse DNS lookup | ✅ | ✅ |
| SRV, CAA lookups | ✅ | ✅ |
| Website to IP | ✅ | ✅ |
| DNS propagation check | ✅ | ✅ |
| Per-record-type pages | ✅ | ✅ |
| SPF / DKIM / DMARC validation | ✅ Full + scoring | ❌ |
| Blacklist check | ✅ 50+ lists | ❌ |
| SSL certificate analysis | ✅ | ❌ |
| Domain Trust Score | ✅ | ❌ |
| AI remediation (Prism) | ✅ | ❌ |
| MCP server | ✅ | ❌ |
| Domain monitoring | ✅ | ❌ |
| White-label reports | ✅ | ❌ |
| API access | ✅ | ❌ |
| Learning / DNS education | ✅ | ✅ |
| Programmatic domain pages | ✅ /scan/<domain> | ✅ /domains/<domain>/ |
| Paid tier | ✅ | ❌ (free + ads) |
Pricing
nslookup.io
Entirely free — no paid plans, no account required, no signup. Revenue comes from advertising.
DomainScan
| Plan | Price | Domains | Highlights |
|---|---|---|---|
| Free | $0 | 1 | All 50+ tools, no signup for lookups |
| Pro | $9/mo | 10 | All monitors, alerts, API, MCP |
| Team | $29/mo | 50 | + PagerDuty, Discord alerts |
| Agency | $79/mo | 200 | White-label reports, client portal |
Where nslookup.io Wins
Pure lookup UX. nslookup.io’s interface for running a DNS lookup is clean and fast. The layout presents record results in a readable format without visual clutter. If you just need to quickly check what a domain’s MX records are, nslookup.io is pleasant to use.
Programmatic domain pages. Their /domains/<domain>/webservers/ pattern creates individual pages for major domains (Google, YouTube, Facebook) that rank for specific domain infrastructure queries. This is a smart content architecture that generates significant long-tail traffic.
Dedicated record-type pages. The /mx-lookup/, /txt-lookup/, /cname-lookup/ structure gives each record type its own ranking surface — which both helps users find the right tool and builds topical authority for the site.
Free with no friction. No account, no rate limit prompts on basic lookups, no signup gates.
Where DomainScan Wins
The question that always follows the lookup. When you query an MX record and get a result, the next questions are: Is SPF configured? Is DKIM signing working? Will email pass DMARC? Is this mail server IP on any blacklists? nslookup.io answers “what is the record” — DomainScan answers “is it healthy?”
Email authentication. This is the largest gap. nslookup.io has no SPF validator (syntax check, lookup-count analysis, include: chain tracing), no DKIM prober (checks common selectors, validates key bits), and no DMARC analyzer (policy strength, alignment mode, reporting configuration). For anyone setting up email for a domain or diagnosing deliverability issues, these are the critical tools — and nslookup.io doesn’t have them.
Blacklist visibility. A domain can have perfectly correct DNS records and still have its email blocked because an outbound IP is listed on Spamhaus SBL. nslookup.io doesn’t check blacklists. DomainScan checks 50+ lists and identifies listings with their impact level and direct delist links.
AI-powered analysis. nslookup.io returns raw records. DomainScan’s Prism AI reads those records, checks them against RFC specifications and best-practice benchmarks, and writes specific remediation steps. “Your SPF record includes ?all which provides no protection — change to -all to block unauthorized senders” is categorically different from displaying the raw SPF string.
Monitoring. nslookup.io is a lookup tool — you check when you think to check. DomainScan watches continuously: when your domain appears on a blacklist, when a DNS record changes, when your SSL certificate enters its 30-day expiry window, when DMARC alignment breaks. Proactive alerting changes the entire security model from reactive to preventive.
MCP for developers. DomainScan’s MCP endpoint lets any MCP-compatible AI assistant (Claude, Cursor, etc.) invoke domain checks programmatically. No equivalent exists in nslookup.io.
The Practical Workflow
Many developers and sysadmins use both tools at different points:
- Quick DNS record check → nslookup.io (fast, no friction, clean UX)
- Pre-launch domain health audit → DomainScan (full analysis: DNS + email auth + blacklists + SSL + AI report)
- Diagnosing email deliverability → DomainScan (SPF/DKIM/DMARC + alignment + blacklist + Prism diagnosis)
- Setting up DNS monitoring → DomainScan (alerts for changes, expirations, listings)
nslookup.io is an excellent drill. DomainScan is the toolbox.
If you only ever need to know “what does this DNS record say right now,” nslookup.io is perfectly suited. If you need to understand whether your domain’s email will be delivered, whether your records are correctly configured, and whether any security issues need fixing — DomainScan is the right tool.