Marketing Crafted

From $0 to $4–5K/Month: The SEO-First Marketing Strategy Behind Nslookup.io

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Nslookup.io logo

Ruurtjan Pul

Founder, Nslookup.io

Follow on X

$4K

Revenue/mo

Business Type

SaaS

Monetization

Advertising

Founded

2020

Introduction

A free DNS lookup tool quietly grows to hundreds of thousands of users a month.
The founder adds a course, some ads, a few sponsorships… and suddenly he’s doing roughly “replace your salary” money from a single boring utility.

No funding.
No big team.
No viral launch.

Just:

  • Pick a keyword devs already search.
  • Make a cleaner tool than everyone else.
  • Let SEO compound for years.

That’s the Nslookup.io story.

This is a breakdown of how Ruurtjan Pul went from zero to a serious income with a DNS lookup site, what actually drove the growth, and what you can learn building your own product.

Ruurtjan Pul, founder of nslookup.io


What Is Nslookup.io Really?

Nslookup.io is an online DNS client. You plug in a domain, it spits out A, AAAA, MX, TXT, CNAME, NS, SOA and more, in a clean UI.

It’s built by Dutch maker Ruurtjan Pul, who describes it as “an online DNS client with over 500k monthly active users” on his LinkedIn.

So the vision is simple:

Take something devs already do in the terminal, and make it faster, clearer, and shareable in the browser.


Why He Built It (And Why It Worked)

If you look at Ruurtjan’s background, Nslookup.io wasn’t a random idea.

He’d been tinkering with web projects since school — a one-page school tabloid, an abandoned Flash games site, a long list of half-finished ideas. Over time he realized the problem wasn’t ideas, it was focus: he needed one simple, durable project he could commit to.

When he evaluated ideas, he used three filters:

  • Will it still matter in 10 years? (DNS definitely will.)
  • Can it make money, even if slowly?
  • Am I personally capable of building and maintaining it?

A DNS client passed all three. DNS is infrastructure. It doesn’t trend. It just exists.
And there were already tons of DNS lookup tools… which, in his words on Reddit, was a feature, not a bug:

“I deliberately chose tools that already have tons [of] traffic on existing sites… Competition means a validated idea. You just have to execute better and get the word out.”


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