Making $32,000 Monthly Bootstrapping 3 Micro-SaaS Tools

Hello! Can you introduce yourself and tell us about your business?

I'm Daniel Nguyen. I'm an entrepreneur based in Ho Chi Minh City, Vietnam.

Last year, I launched KTool —a productivity tool for Kindle owners.

Recently, I launched 2 AI apps for Mac users:

• BoltAI: Access ChatGPT on any Mac app

• PDF Pals: Instantly chat with any PDF on your Mac
  

How did you start this business? Take us through the process.

I love building things on the Internet. The first dollar I earned from the Internet was roughly 15 years ago when I was selling a plugin for an open-source forum software called Invision Power Board. Since then I mostly do software consulting & building side projects for fun.

The idea of KTool first came to my mind when I was reading "Ask HN: I'm a software engineer going blind, how should I prepare?"

I've been wearing glasses since I was 5. My right eye is blind. Doctors said there is no chance to cure it.

I was genuinely scared. Like holy crap, if my left eye stops working, my life is done. Since then I've been very conscious about time spent on computer screens.

That's when I started using Kindle-related products: to offload as many reading materials as possible to the Kindle.

Then I ran into multiple limitations, leading me to build KTool, a tool to send your favorite online content to Kindle: blog posts, Twitter threads, Hacker News discussions, RSS feeds, newsletters...

I didn't start it immediately. In the beginning, I tried to validate the idea by asking on Reddit. And the initial idea was a macOS app to send PDF & EPUB to Kindle.

But after building it in public on Twitter, it's clear to me that people won't pay for it. So I kinda pivot into sending articles & Twitter threads to Kindle and got much better traction.

How did you get your first initial customers?

I started building KTool in public in Jan 2022 and soft-launched the beta on Twitter in Feb. I keep improving the product until one day I got super lucky.

Someone mentioned KTool on Hacker News. And I got a couple of sales that day, completely from strangers on the Internet.

I was selling lifetime deals (LTDs) in the early days. After a few months, I reached $3k in LTDs sales, which was pretty good. Much better than I expected.

In July I decided to stop selling LTDs and switched to selling subscriptions instead. It was quite challenging in the beginning. It didn’t gain much traction until I launched KTool on Hacker News. It was a huge success for me - KTool reached the front page and stayed #2 for almost 2 days.

To summarise, it took me about 6 months to acquire 700 users. 56 of them are paying customers.

Since launch, what are your marketing strategies or channels to get new customers?

In the early days, my only growth strategy was to build KTool in public on Twitter. It was both for building a personal brand and to get quick feedback from early adopters.

When I started using Twitter more seriously last year, I immediately got overwhelming support from the founder & indie maker community. I’m probably not the best to talk about growing an audience on Twitter.

The “strategy” that works for me is to share my lessons on bootstrapping KTool & Bolt AI. I occasionally create startup memes and people seem to love it. Some went viral and got over 1M impressions. I plug my product under the viral tweet and that’s it—pretty simple.

Twitter remains the second-best traffic source for KTool.

But spending too much time on Twitter is not scalable. At some point, I felt worn out. So I started to explore other channels. I’ve tried a few different things:

• App Store Optimization (ASO): I developed the Safari extension for KTool and submitted them to the Apple AppStore. I learned more about ASO and was able to rank #1 for the term “Send to Kindle” on the Mac AppStore.

• Engineering as marketing: I’ve built multiple free tools to drive traffic to KTool and to capture their email addresses

• Email marketing: I send monthly product updates and occasional promotions.

• Newsletters sponsorship: I reached out to a few newsletter authors on Twitter

• I tried to run a few Google Ads campaigns

Recently I’ve been putting more effort into SEO and started to see promising results.

ASO is the most performing channel for KTool now. It constantly brings traffic without me doing anything. I think the reason it works is because people actively looking for a solution to spend less time on the computer.

Unlike the iOS AppStore, the Mac counterpart is not as competitive. I was able to rank #1 for a few important keywords on the Mac AppStore, but it’s like #70 or so in the mobile AppStore.

“Engineering as marketing” works pretty well but it’s like launching another product. As a solopreneur, I find it hard to maintain these free tools and keep building new ones.

Paid Ads don’t seem to work. The CAC is too high for a $5/mo product like KTool.

I got mixed results from newsletters sponsorship. Similar to running paid ads, the CAC is too high to be sustainable. So in the end, I decided to not pursue it further.

How does your business make money?

KTool run on a subscription-basis.

KTool reached $1K MRR recently and has generated $12K in total revenue. Monthly expense is about $150/mo.

BoltAI reached ~$14k revenue recently.

After 4 months, PDF Pals generated $6,000 in revenue.

Before you go, what advice would you give to another who wants to start a business like yours?

Getting started is always the hardest.

The fear of failure is strong. Rejections hurt. My advice is to get past that “first scary moment” as fast as you can. Just start and figure out the rest on the go. Launch fast, don’t wait until the product is perfect (hint: it never will be) Most of your decisions are reversible, so better to make one now that you can learn from and adjust later than to not decide at all.

If you have a technical background like me, don’t make the mistake of spending all your time on product and development.

Spend at least 50% of your time on sales and marketing. Entrepreneurship is exciting but it will likely be the most challenging thing in your career.

Join a supportive community such as Indie Hacker or Twitter maker community.

Where can we go to lean more about you and your business?

Here are some links you can go to learn more:

• Twitter

• Blog

• BoltAI

• PDF Pals

• KTool