Building for himself and growing his portfolio to $10k+/mo

While Sergiu Chiriac was launching product after product, he built a tool for himself that helped him to submit new products to directories. Then, he turned that into a customer-facing product. Now, AI Directories brings in the lion's share of his portfolio's $10k/mo revenue.

Here's Sergiu on how he's doing it. 👇

Building for himself

Hi, I'm Sergiu, a software engineer with over ten years of experience building web applications and SaaS products. In 2023, I started my indie hacking journey, turning side projects into real businesses. Since then, I've launched multiple AI startups, learning not only how to build products but also the difficulty of marketing them. That shift from developer to entrepreneur taught me that distribution is often harder than development.

A recurring challenge with every launch was product discovery. Each time I released a new tool, I manually submitted it to dozens of startup and AI directories to gain visibility, backlinks, and early users. After repeating this process for several products, I built an internal tool to save myself time. That became AI Directories.

Soon, other founders asked for the same help, and it evolved into a service that has now helped 900+ founders launch and promote their startups through 100+ curated directories.

Today, besides AI Directories, I'm also building other products:

• TransClipper: An AI-powered tool that extracts and analyzes transcripts from short-form videos

• BrandReply: This will help brands track and improve their visibility across AI assistants

• And a few stealth projects.

My revenue varies monthly because most of my products are one-time purchases rather than subscriptions. Across all my projects, I typically generate over $10k/mo. Last month, I hit a personal record of $15.7k. AI Directories was $9.5k of that.

Starting slow

I started indie hacking in 2023 because I realized I wanted to build products for myself, not for other companies.

I didn't quit my job overnight. I started launching AI tools on nights and weekends, learning product development, marketing, sales, SEO, and customer support. My goal wasn't to build a single company — it was to create a portfolio of profitable internet businesses.

So, I built everything gradually, reinvesting profits from one project into the next. That approach allowed me to experiment, fail, learn quickly, and eventually grow a portfolio.

Building a feedback loop

The first version of AI Directories didn't require a huge budget, but it did require a lot of time. As a software engineer, I built everything myself — from the website and dashboard to the submission tracking system. The biggest investment wasn't coding; it was researching and manually validating directories. I spent countless hours finding startup and AI directories, checking their activity, measuring their SEO value, understanding their submission requirements, and organizing them into a curated database.

I funded the project entirely with revenue from my previous side projects, so no outside investment was needed. I kept expenses low by using familiar tools and leveraging AI to speed up content creation and repetitive tasks. Instead of trying to build a perfect product, I focused on solving one problem well: helping founders get their products listed in high-quality directories without wasting hours doing it manually.

I became my own first customer, which was a key advantage. Every time I launched a new product, I used AI Directories to submit it, which helped me continuously improve the service based on real experience. That feedback loop was invaluable because I didn't guess what founders needed — I solved the same problems I faced myself. As more founders started using the service, their feedback helped shape the product into what it is today.

The challenges of indie hacking

My biggest challenge has been staying focused. As an indie hacker, new trends and ideas easily distract me. Looking back, I should have spent more time improving products already making money instead of constantly starting new ones.

I've also had a few projects with cofounders that didn't work out. Those experiences taught me that I work best on my own. I prefer building the product, doing the marketing, and being responsible for the results instead of relying on someone else.

Burnout was another challenge. In the past, I often worked more than 14 hours a day, seven days a week. Now, I put my health first. I keep weekends for rest and sometimes take a few hours off during the week to recharge.

It's important to remember that long-term consistency is more important than working nonstop.

The tech stack

I build my products with Next.js, MongoDB, Prisma, and Tailwind CSS. I use Prisma to simplify database management and OpenAI, Gemini, and Anthropic APIs to power AI features and speed up development.

I originally hosted most projects on Vercel, but later moved some of them to Coolify to reduce costs. I still use Vercel when it makes sense for smaller projects or quick deployments.

For payments, I use Stripe because it is fast and easy to set up. I use Resend for emails because it is developer-friendly and simple to integrate. Cloudflare handles DNS, image storage, caching, and security.

The main challenge is keeping costs under control while managing several products, so I regularly adjust my stack to balance speed, simplicity, and expenses. AI has also become an essential part of my workflow — not only for product features but also for coding, debugging, writing content, and brainstorming ideas, allowing me to build much faster as a solo founder.

Expand with your customers

AI Directories started as a simple service where founders paid a one-time fee for me to manually submit their products to more than 100 curated startup and AI directories. I started charging from day one because I knew the process saved founders hours of work, helping them gain visibility, backlinks, and early users.

As the business grew, I realized founders needed more than launch submissions. Today, AI Directories has become a broader distribution platform. Founders can submit their products directly to our own directory for $49. This includes a DR70 dofollow backlink, exposure to our community, and inclusion in our newsletter. We also offer services like guest posts, sponsored placements, and other promotional opportunities to help founders reach a larger audience.

Revenue grew by expanding services rather than changing the original business model. Instead of relying on a single offering, AI Directories now has multiple revenue streams that complement each other, serving the same audience of startup founders.

That's why my advice is to start by solving one problem really well. Once people trust your product, listen to their other needs. Expanding with the same customer is often much easier than constantly looking for new markets.

Distribution from the get-go

As far as growth, my biggest advantage is being my own customer. When I launch a new product, I use AI Directories for distribution and early traction. Consistently launching on startup and AI directories helps me get initial users, backlinks, and search engine visibility. I dogfood my own products to validate both the product and the service simultaneously.

Beyond directories, I share my journey on X and Reddit. I post product updates, lessons learned, milestones, and engage with founders in communities where my target audience already spends time. I also conduct targeted cold email outreach to introduce AI Directories to startups that could benefit from it.

Long-term, SEO has been my biggest growth channel. I invest heavily in creating useful content, building high-quality backlinks, and optimizing my sites for organic search. More recently, I've focused on GEO (Generative Engine Optimization) to improve visibility in AI-powered search engines and assistants. I believe AI search will become an increasingly important acquisition channel. This is why I'm building BrandReply — a platform that helps businesses monitor and improve how AI assistants and LLMs mention them. Organic traffic, whether from traditional search or AI-powered search, has become the most sustainable source of customers across my portfolio.

My growth advice is to build your marketing engine as early as you build your product. Distribution isn't something to think about after launch — it should be part of the product from day one.

Five pieces of advice for indie hackers

My most important advice: don't start by building — start with research. Before writing a single line of code, study your competitors. Look at their traffic, how they make money, what customers like and dislike, and assess if you can realistically build something better or different. Competition is a good sign because it proves a market exists.

After your research, validate the idea. Talk about it on X, Reddit, or other communities where your target users hang out. Observe their reactions. If nobody cares about the problem, it's better to discover this before spending weeks building.

I also recommend building something you would use yourself. Solving your own problem makes it easier to understand your customers, identify essential features, and stay motivated when difficulties arise. Most of my successful products started because I needed them first.

Keep your first version as small as possible. Build one feature that solves one problem well, launch it, and improve it based on real feedback. Don't fall in love with a product that isn't making money. Test new ideas, learn from the results, and don't be afraid to move on if something isn't working.

Finally, use AI as your cofounder. It can assist with coding, design, content, marketing, customer support, and brainstorming. It enables a solo founder to build much faster than ever before. Show up every day, stay consistent, and remember that building a successful business is a marathon, not a sprint.

What's next?

My goal is to build a portfolio of useful startups that solve real problems and grow my revenue year after year. Rather than relying on a single business, I enjoy building multiple products that complement each other and create long-term value.

I also want to help other founders succeed. Whether through AI Directories, sharing my journey publicly, or creating tools that make entrepreneurship easier, I enjoy seeing others launch and grow their businesses.

If I can build products I enjoy, help other entrepreneurs, and create the freedom to spend more time with my family while doing meaningful work, I'll consider that a success.

If you'd like to follow along, I'm very active on X, where I regularly share what I'm building, lessons I've learned, revenue updates, and insights from my journey as an indie hacker. You can follow me there.