Hey, all!

Just wanted to share a quick update since my last post.

RPBuddy.ai Home Page

RPBuddy is now multi-genre. We started out with medieval only (helped me focus on developing the gameplay, plus I enjoy it a lot), but now you can build and play in four completely distinct settings:

• Medieval Fantasy - kingdoms, taverns, magic, and classic adventure
• Modern Day - cities, contemporary stories, intrigue, and everyday drama
• Neon Future - cyberpunk megacorps, hackers, neon streets, and high-stakes tech
• Sci-Fi Colony - alien frontiers, space outposts, survival, and distant-world exploration

Multi-character chat

https://preview.redd.it/a120jtre48zg1.png?width=1609&format=png&auto=webp&s=ed4f591e6f6213a0487d460d11eae0db3aae84e3

World creation

Each genre has its own buildings, NPC roles, economies, dialogue flavor, name generators, and even unique map aesthetics. Switching genres feels like loading a brand new game while keeping everything that makes RPBuddy special: hex-based worldbuilding you control, persistent NPCs with real memory and relationships (they gossip, remember conversations, and evolve over time), turn-based combat, full inventory/economy, AI-generated building interiors and character portraits in 5 different styles, and over 400 music tracks to set the right mood.

There’s a completely free starter world (fully populated with 200+ NPCs) you can jump into right now just to see how it all comes together, before signing up for the free trial you can view the NPCs and all of their profiles, see their images, explore the map :)

https://rpbuddy.ai

Join our Discord, ask questions, share screenshots, chat about anything RP: https://discord.gg/ejppJUc3QS

Cheers! -J

RPBuddy (rpbuddy.ai) is a browser-based AI RPG sandbox where you build a hex map world, populate it with NPCs that have their own daily routines and relationships, and then explore it through visual novel-like AI-driven conversations.

Think less "chatbot with a fantasy skin" and more "living world simulator with an RPG layer on top."

What it actually does

You start by painting a hex map with biomes, roads, rivers, and settlements. Then you place buildings and generate NPCs for them. Each NPC gets:

• A daily schedule where they move between buildings on the road network using actual Dijkstra pathfinding
• Hidden motivations like a goal, a fear, and a secret that shape how they behave (you never see these in conversation, but they're always influencing it)
• Persistent memory so every conversation is summarized and stored. NPCs remember what you told them, what they heard through gossip, and how they feel about it
• Relationships where NPCs form opinions about each other and about you, and those opinions shift based on what happens The gossip system is probably the thing that surprised me most. NPCs who cross paths during their daily routines share information. So if you tell the blacksmith something scandalous about the mayor, it can propagate through the whole settlement over a few in-game days, and NPCs react to it based on their own motivations.

There's also a journal that tracks your story, a combat system for encounters while traveling, quests, inventory, AI-generated portraits for every character, and ambient music.

The business side (since this is r/SideProject)

I launched a short alpha a few weeks ago, and got lucky with a few testers who hammered me with amazing feedback and great encouragement, and as of Friday we are now live. Early signs are encouraging. I've got signups coming in, a small Discord community forming, and just landed my first trial subscriber who's a complete stranger (not a friend, not an alpha tester). That one felt good.

Pricing is $10/month for the base tier. I designed the architecture from the start with cost efficiency in mind. Model selection, when and how often to call the LLM, what to cache vs. regenerate. The unit economics actually work. This isn't a product that bleeds money per user, and I pressure-tested it during alpha.

The infrastructure runs lean too. Total fixed costs are under $50/month, which means the path to ramen profitability is short.

Decisions that came from working in startups

I'm the solo developer on RPBuddy, but this isn't my first rodeo in the startup world. I work at a couple other startups and have seen enough good signs and bad signs to know which decisions matter early. My wife and I are both passionate about AI RP and worldbuilding. She brings the narrative writing expertise, I bring the engineering and business side. It's a good split.

Some of the things I thought hard about before writing a line of code:

No free tier. This is one I feel strongly about. If you don't have real funding behind you, a free tier will eat you alive. Every free user on an AI product costs you money, and you end up subsidizing people who were never going to convert. Trial with a card required. That's it. It filters out throwaway accounts and means every user in the system is someone who at least considered paying.

Content safety from day one. This is an AI product where users have open-ended conversations with NPCs, and that means you have to think about what can come out the other side. I have a content safety model in the pipeline because I work in AI and know this isn't optional. You either build safeguards early or you're scrambling to bolt them on after something goes wrong publicly. Especially for a product that could attract younger users, even though we enforce 18+.

Cost modeling before feature building. I tracked per-user costs during alpha with real usage data, not projections. I know what a heavy session costs, what an average month looks like, and where the margin sits at each pricing tier.

Don't build five features that half-work. Build one that fully works. I cut LLM-generated quests entirely because they were unreliable. Shipped with one procedural quest type (enemy bounties) that works every time. It's less impressive on paper but way better in practice. Overpromising and underdelivering kills trust fast, and I've seen it happen.

Other things I learned along the way

Start with the system, not the features. I spent a lot of early time on the simulation engine (pathfinding, scheduling, memory architecture) before building any of the flashy stuff. That foundation is what makes everything else feel alive rather than scripted.

Your most powerful feature might be the cheapest one. The NPC motivation system (goal/fear/secret) is literally three strings stored at creation time. Zero ongoing LLM cost. But it's one of the biggest drivers of interesting NPC behavior.

Screenshot-driven products have an unfair marketing advantage. When I post a screenshot of the hex map or a cinematic conversation, people stop scrolling. When I try to explain the gossip system in text, eyes glaze over. If your product looks like a game, lean into that hard.

Test your full signup flow on production before you tell anyone about it. I had a redirect bug in my auth flow that was silently sending people to a dev URL. Almost certainly lost early conversions before I caught it. Embarrassing but important.

Tech stack (for the curious)

React + Pixi.js frontend on Vercel, Express.js backend on Railway, SurrealDB for the database, Clerk for auth, Stripe for payments. LLM calls go through OpenRouter so I can route different tasks to different models based on cost/quality tradeoffs. Image generation through fal.ai.

What's next

The immediate roadmap is genre expansion. The platform is built to support different settings beyond medieval fantasy (modern urban, cyberpunk, horror, etc.), and I think that's the single biggest growth lever. But first I want to validate that the core medieval fantasy crowd sustains before investing in that.

Right now I'm mostly heads-down on marketing and polish. If you're into solo RPGs, worldbuilding, or just want to see what an AI-driven living world looks like, I'd love feedback: rpbuddy.ai. No pressure to sign up for the free trial if you are just curious about the overworld map, I just added a read only feature to the starter world that lets you look at the map, hover over buildings, see character portraits and profiles before you even have to enter a credit card (:

Happy to answer questions about the architecture, business model, or anything else.

Thanks for reading!