solfox

Hi HN, I’m Sol (YC06). I built BestInterest (https://bestinterest.app) solo to help co-parents communicate peacefully after divorce. It was just featured in WIRED (https://www.wired.com/story/ai-emotional-spellcheck-difficul...) - without any PR.

The idea came from personal experience — a painful divorce and challenging co-parenting communication. Courts often tell co-parents to keep things business-like and child-focused, which sounds simple but is brutally hard in practice. I realized AI can do what humans often can’t — remove emotion from the loop. It started as a simple theory — that AI could actually prevent emotional abuse in digital communication.

I’d taken a break from tech after years at Google (I was a PM there), but eventually brushed off the dusties and decided to build it myself.

THE STACK

Google Cloud + Firebase + Gemini (with some OpenAI functionality still in place) + Twilio. Front end: FlutterFlow. I bootstrapped everything — no funding, no team at first, just persistence, a supportive partner, and late nights after my kids were asleep. One upside of co-parenting: suddenly, a lot of kid-free time to think/code.

Early on, I knew I wanted an advisor with deep expertise in abuse recovery. During my own healing, Dr. Ramani Durvasula’s YouTube videos were life-changing, so she topped my “never-going-to-happen” list. I cold-emailed her — and to my surprise, she said yes.

Yesterday, WIRED featured our story: “Divorced? With Kids? And an Impossible Ex? There’s AI for That.” Side note: in the article, our leading competitor acknowledged using users’ personal correspondence for training data — which was… surprising.

It’s surreal seeing something that began with personal pain now helping others in such a profound way. I get emails every week from customers saying the app has changed their lives. It’s incredibly gratifying.

I’m learning as I go — building in a space this sensitive has challenged me in many ways and shown just how deeply this kind of technology is needed.

I was “fortunate,” in a strange way, to have lived this pain firsthand; it helped me understand what was needed for my niche. AI has just as much potential to create harm or false information as it does to bring light to dark places — protecting victims and helping people find safety in their communication.

Happy to talk about any of these:

- Bootstrapping a consumer AI app solo

- Restarting life as an entrepreneur after kids, a divorce, and an eight-year hiatus

- Transitioning to being a full-time dad (9 years ago)

- Growing a real subscriber base in a niche without a marketing budget — leveraging AI and SEO

- Building for a legally and emotionally complex community

- Using AI to protect against abuse — designing filters that help without over-censoring

- Breaking into a quasi-regulated industry where many assume court approval is required just to operate

AMA — happy to talk about the journey, the challenges, or anything else that resonates.

Hi HN, I’m Sol (YC 2006). I built BestInterest to help co-parents communicate peacefully after divorce or high-conflict relationships.

The idea came from personal experience — a painful divorce and difficult co-parenting communication. Courts often tell co-parents to keep things business-like and child-focused, which sounds simple but is brutally hard in practice. I realized AI can sometimes do what humans can’t — remove emotion from the loop. It started as a simple theory — that AI could actually prevent emotional abuse in digital communication.

I’d taken a break from tech after years at Google (I was a PM there), but eventually brushed off the dusties and decided: I’ll build it myself.

THE STACK

Google Cloud + Firebase + Gemini (with some OpenAI functionality still in place). Front end: FlutterFlow. I bootstrapped everything — no funding, no team at first, just persistence, a supportive partner, and late nights after my kids were asleep. One upside of being a co-parent is suddenly a lot of kid-free time to think!

Early on, I knew I wanted an advisor with deep expertise in abuse recovery. During my own healing, Dr. Ramani Durvasula’s YouTube videos were life-changing, so she topped my “never-going-to-happen” list. I cold-emailed her — and to my surprise, she said yes.

Yesterday, WIRED featured our story: “Divorced? With Kids? And an Impossible Ex? There’s AI for That.” Side note: in the article, our leading competitor acknowledged using users’ personal correspondence for training data — which was… surprising.

It’s surreal seeing something that began with personal pain now helping others in such a profound way. I get emails every week from users saying the app has “literally changed their lives.” It’s incredibly gratifying.

I’m learning as I go — building in a space this sensitive has challenged me in many ways and shown just how deeply this kind of technology is needed.

When used with care and intention, AI can genuinely help marginalized communities — people navigating conflict, isolation, or trauma. I was “fortunate,” in a strange way, to have lived this pain firsthand; it helped me understand what needed to be built for my niche. AI has just as much potential to create harm or false information as it does to bring light to dark places — protecting victims and helping people find safety in their communication.

Happy to talk about any of these:

- Bootstrapping a consumer AI app solo

- Restarting life as an entrepreneur after kids, a divorce, and an eight-year hiatus

- Transitioning to being a full-time dad

- Growing a real subscriber base in a niche without a marketing budget — leveraging AI tools and SEO

- Building for a legally and emotionally complex community

- Using AI to protect against abuse — designing filters that help without over-censoring

- Breaking into a quasi-regulated industry where many assume court approval is required just to operate

- Or what it’s like designing tech for the most emotionally charged messages imaginable

AMA — happy to talk about the journey, the challenges, or anything else that resonates.