Jonas Kamber @jonaskamber

It’s been 3 months since I launched. And Mono just hit $50,000 ARR. But let me start from the beginning. About half a year ago, two strangers agreed to buy an annual subscription for Mono, knowing that I had to build it first. This gave me the confidence to go all in. Since that day, I have been shipping every day. I share my progress publicly. Wins like this, but also the struggles that come with building a business from scratch alone. This week, I released the Anonymization feature that triggered people to upgrade from a Pro to a Business account, helping Mono reach $50,000 in ARR. Now I’m working on getting to $100,000. Will it take another 3 months? I believe I can get there faster. The road had its share of obstacles. Things I never expected to deal with. But not once did I doubt this is exactly where I'm supposed to be. I'm just getting started.

People reading a ChatGPT response after a few days with Claude. (Yes, I built an app that lets you use both. No, you won't go back.)

Every large language model hallucinates. The question isn't "which AI never lies?" It's "how do you catch it when it does?" Here's how Mono tackles this: 1. Simply request a second opinion: Not sure if your model got it right? Request an answer from another model with one click. 2. Dead links show immediately: When a model references a source that doesn't exist, Mono flags it. Hallucinated citations become impossible to miss. 3. Multi-model research: When accuracy really matters, Mono lets multiple models research the same topic simultaneously and challenge each other's answers. Mono cannot prevent hallucinations. But it helps you deal with them.

ChatGPT hallucinates differently than Claude.

Week 21 of building in public. Honestly, not my best week. Focus has been a struggle. Starting next week, I'm committing to more planning instead of bouncing between tasks. LinkedIn impressions dropped again. 20k per week might just be the new baseline. Whether I'll ever hit 200k again, time will tell. The April Fools post on my profile and the Mono page were small wins, though. Sometimes you need a little joy in the feed. On the product side, I shipped a new mode built specifically for analysing large amounts of data in files. Mono's automatic model selection kept picking small, fast models that fell apart with large datasets. I improved the categorization and used Gemini Pro for these tasks. Results are much better now. I also added a new model: MoonshotAI Kimi. Worth trying if you haven't. It often reasons a bit too long for my taste, but I like the answers. On the marketing side, I created 2 video ads. They now run on YouTube. The iteration cycle starts now. Ad prices on YouTube are significantly higher than when I last ran campaigns 10 years ago. Will see if I can run these ads profitably. Still exploring affiliate partnerships. Currently talking to Impact and PartnerStack. Both platforms are clearly built for enterprise, with long onboarding cycles and high upfront costs. I hope they can help me reach creators willing to promote Mono, which is not as easy as I thought. Revenue is growing, which feels good considering it's all still organic. But I start to feel the urge for faster scale again. The product is ready now. Off to a better week ahead.

Annual revenue increased by almost $20k in March. But net loss increased, too. Here's why: In February, 27% of new customers chose an annual plan. In March, that dropped to just 3.2%. Two things happen when that shift occurs in a SaaS business: 1. Customers who paid annually in February bring in 0 revenue in March 2. Fewer annual subscribers in March means less upfront revenue for that month Infrastructure costs have more than doubled. More users, and a new vendor (Firecrawl), which is heavily used in Multi-Model Research. I hope it's worth it. Here's exactly where the money went: → Tools: LinkedIn Premium: $63, Google Workspace: $50, Cursor: $20, Figma: $15, Bank fees: $30 → Accounting: $206 → AI APIs: $781 → Infrastructure: Google Cloud: $91, Firecrawl: $180, Resend: $20, Namecheap: $1 → Compensation: My salary: $8687, Payroll taxes: $1216 Net loss increased by $98 despite the growth. That's a temporary effect. And the infrastructure in place can serve significantly more customers at the same cost. The biggest cost factor is still my salary. New subscribers every day means the gap between revenue and costs is closing. Slowly, but steadily. Overall, I'm happy with where Mono is heading. The growth is solid, and the UX improvements this month were meaningful. April, let's goooo 🚀

A new era in UI design emerges. Let me introduce: Really Dark Mode This new mode takes what everybody loves about dark mode and brings it to another level. No more distractions. No more light that hurts the eyes. Just pure tones of black and dark grey. Because if you truly trust AI, you don't need to read the answer. And if you're not ready to give up control, you can always switch back to good old regular dark mode. Happy April 1, everyone. 🖤

Today is a good day. Because I just released a big update. It makes the core interface on Mono (mono.chat) so much better. → The selected AI is now always visible → The Multi-Model-Research option is no longer hidden behind a menu → There is even a subtle color change whenever you’re using Claude, GPT, Gemini, Mistral, or Perplexity This is only one of several UX improvements I’m launching over the next couple of days. If you see something I should improve, let me know. Hope you like the new chat box design.

Poor performance on LinkedIn, exploding revenue 💥 This was week 18 of #buildinpublic. Let’s get into it. → I've spent 10+ hours crafting LinkedIn posts that provide real value. None of them resonated. I'm staying on it. → Referrals work incredibly well. I focused on different initiatives to fuel that fire. → In that process, I introduced a bug that sent emails multiple times to about 100 people. I'm sorry if you were affected. Fortunately, the complaint rate stayed at 0%. → I researched whether I could offer a European-only model option, so your data never leaves Europe. More on that soon. → Mono added another $7,716 ARR this week. The fastest-growing week yet. Next week, I'm improving what's already working before adding anything new.

Woohoo, that was fast! 🎉 Mono just hit $30,000 ARR, updating the milestone to $40,000. Word of mouth is the main driver. Customers recommending Mono to others. And it's snowballing. From 1,000 to 10,000 in 65 days From 10,000 to 20,000 in 15 days From 20,000 to 30,000 in 10 days Still building alone. Still 100% focused on building a better ChatGPT. It’s an incredible journey.

Day 88 of #buildinpublic While Mono approaches $30,000 in ARR, I'm in #UX design mode. A new chat box design puts all options in plain sight. No more hidden menus. A subtle color change that makes it clear which model is active. And more updates are coming. Better memory handling control. Smaller details that have been bugging me for weeks. This version will be the best version.

New milestone reached. 🙌 Yesterday, the 500th human signed up on Mono. All through my posts on LinkedIn, building in public, and happy users telling their network. Still $0 spent on marketing. And I'm getting a lot of positive feedback on the new Multi-Model-Research feature. This will likely drive the next 500 sign-ups. 🙌

Biggest feature. Fastest growth. This is week 17 of building Mono in public. Let's get into it. → LinkedIn impressions are still flat. I tried different angles and formats. Nothing clicked yet. I'll keep experimenting. → User growth was strong. Different customers posted about their experiences with Mono and motivated their network to make the switch. That was one of the biggest growth drivers. Mono almost hit 500 users. → The option to exclude OpenAI models was a big success. It brought in new users, and more people than I expected had opted out of OpenAI models. → Multi-model research is live. Users voted for this feature, and the interest was real, but the launch email and posts got much less engagement than I hoped. → Revenue is growing faster and faster. +$6,516 ARR added in 7 days (+40%), putting Mono to $22,620 ARR. I need to remind myself not to take this growth for granted. The first two channels are working like a charm. I hope the third one I start building next week will do the same.

Isn’t growth supposed to slow down 5 weeks after launch? It seems to accelerate. Just 15 days to go from $10'000 to $20'000 ARR. → Still building alone. → Still $0 spent on paid ads. → Still 100% product focus. What makes me especially happy: → People start posting about Mono → Everyone keeps their subscription (0% churn) Next milestone: $30'000 ARR

People on X like to say LinkedIn is cringe. It sometimes is. But you can also create momentum there. When Ioana Teleanu posted about canceling her ChatGPT subscription, 384 people liked it. I had a feature idea, jumped in, pitched it, and it resonated. Don't ignore LinkedIn, it's the main driver for Mono's growth ($18'828 ARR, 5 weeks after launch)

I just analyzed Mono's last 100 sign-ups (minimum 10 days ago). 22 people converted to paid subscribers. Average time to upgrade also improved from 5.4 days to only 3.3 days. For context: → Most SaaS get 1-2% conversion → Top products like ChatGPT reach ~5% → Mono is at 22% Never seen anything like it.

New growth record this week. 🙌 But LinkedIn impressions took a dip. I posted less general #AI content (which tends to reach more people) and more about building Mono in public. Finding the right balance between reach and conversion is something I'm working on. The upgrade rate hit 14% today. Out of 100 people trying Mono, 14 buy a subscription. This is incredibly high. Mono is getting a major update next week. A handful of early users already have access to Multi-Model Research. Mono lets Gemini, Claude, and GPT research a topic, cross-check through web searches, and combine findings into a summary paper. The goal: more thoughtful, well-balanced, and hallucination-free answers for complex questions. I plan to release this next week, depending on the feedback of early testers. Growth keeps accelerating. Mono added $4,092 this week, hitting $16k ARR for the first time.

The rare moments you realize the power of an idea in product development. I just had such a moment. Let me explain. Mono lets you use all major LLMs side by side. You prompt, Mono selects the best model. Not happy with an answer? Select an alternative. But what if they worked together as a team? We know diverse teams are more successful. So I started building a Multi-Model Research feature for Mono. It’s like ChatGPT's Deep Research, but with checks and balances. Gemini Pro, GPT 5.2, and Claude Opus each conduct research, orchestrated by Mistral. So I asked it how much screen time is ok for my daughter. The results made me pause. The combined answer is more balanced and thorough than any individual response. But I wanted to see the differences. So I added a section highlighting each model's weaknesses and blind spots. This section is more powerful than I expected. It reveals what Claude, Gemini, and GPT each missed. Showing clearly how much more powerful this multi-model approach is. Should Grok be included as well?