Meet NucleusYour virtual co-founder.
Your virtual co-founder for
Talk through your idea out loud. Nucleus stress-tests it, finds real users for you to interview, and turns what you learn into a plan you can actually build from.
It's free to get started!
The co-founder that pushes back.
You talk, Nucleus listens, then it stress-tests your idea, tracks your assumptions, lines up real people for you to interview, and turns what you learn into a plan you can hand straight to your build tool of choice. It remembers everything about your startup, so no session ever starts from zero.
Most AI tools just tell you what you want to hear: ask if your idea is good and they'll say yes, every time. That false confidence is why so many AI-built products launch to zero users. Nucleus grounds every next step in real evidence: customer conversations, market numbers, and your own validated assumptions.
Built for the founder who already has the idea, and the AI tools to build it. Nucleus brings the missing piece: a co-founder who keeps every step grounded in real evidence, not just enthusiasm.
Watch a session with Nucleus unfold
Product philosophies guide every conversation you have with Nucleus.
- 01
One idea at a time
Splitting focus across ideas is the fastest way to finish none of them. Nucleus keeps you locked on one at a time.
- 02
Always talk to potential users
Nucleus surfaces people from your LinkedIn network worth talking to, so validation never stalls for lack of a lead.
- 03
Set a clear assumption and rank by risk
Nucleus sharpens vague hunches into testable assumptions, then ranks them by what matters most to get right first.
- 04
Break products into features and prioritize
Nucleus turns a broad idea into scoped features and phases, so you ship the smallest valuable slice first.
- 05
Launch early, get feedback, experiment fast
Nucleus writes a build-ready plan sharp enough to hand straight to your vibe-coding tool of choice.
- 06
Distribution makes or breaks consumer products
Nucleus pushes you to nail distribution before you go deep on the build, so you never ship into silence.
Loved by founders
“I like the interface, it's very natural to talk and create ideas.”
“Nucleus forced me to think a lot. It wanted specific answers, and so different from LLMs. I would recommend this to all founders.”
“Nucleus keeps asking me why over and over again, forcing me to get crystal clear on my idea. The distribution planning for the launch was also surprisingly detailed and useful.”
Pricing
Free
Get a feel for Nucleus, no card required.
- 30 minutes of voice conversation
- Brainstorming with Nucleus
No credit card needed
$20/month
Launch offerYour co-founder available 24/7 on voice and text.
- Everything in Starter, plus:
- 20x more conversation time
- Turn a raw idea into a sharp, testable assumption
- Get matched with real users worth interviewing, sourced from your own network
- Walk out of every customer chat with a clear script review of what you actually heard
- Competitor analysis and market trend tracking
- Data-grounded market sizing for your idea
- Ship a product plan reviewed from every angle you'd have missed alone
- See your momentum session to session, so you always know the next move
- Proactive research that keeps working even when you're not talking to Nucleus
Cancel anytime. No lock-in.
Frequently Asked
1. What is Nucleus?
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Nucleus is a voice-first co-founder that stress-tests your ideas, keeps your startup memory (ideas, assumptions, customer chats, product plan) in one place, and pushes back instead of flattering you.
2. Is Nucleus for me?
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Yes, if you've got an idea and the AI tools to build it, and you want a co-founder who keeps you grounded in real evidence as you go. Aspiring founders, solo builders, and anyone chasing a side project with real business potential all fit.
3. Is there a free version?
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Yes. Starter gives you 30 minutes of voice conversation for idea brainstorming, no card required. Pro ($20/mo) gives you 20x more conversation time plus the full validation, research, and planning toolkit.
4. What do I get with Pro?
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Pro ($20/mo) gives you 20x the conversation time of Starter, the full validation toolkit (sharpening ideas into testable assumptions, real customer-interview matching, product planning, momentum tracking), and proactive research that keeps working in the background between your conversations.
5. Will Nucleus build my product?
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No. Nucleus is a strategic co-founder. It helps you validate and scope what to build; you (or your own tools) handle the code.
6. Is everything I build here mine?
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Yes. Every idea, assumption, product plan, and customer chat you create is saved under your account and yours to keep. Pull it up any time and download it as a PDF, individually or all at once. That includes the research Nucleus does on its own between conversations.
7. Is my data private?
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Yes. Your conversations, ideas, and documents are stored in Nucleus's own database, tied to your account, and we don't sell your data to third parties. To power the voice experience, your audio and transcripts are processed by our AI providers (Deepgram for speech-to-text, Google Gemini for the AI itself, Smallest AI for text-to-speech) only to generate that session's reply.
8. How is Nucleus different from just using ChatGPT?
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A general chatbot answers whatever you ask and moves on. Nucleus is built to be a co-founder: it remembers your idea, assumptions, and customer chats across every session, pushes back with pointed questions instead of agreeing with you, and keeps you moving through validation and planning one idea at a time instead of a blank text box.