The Bottom Line: Alloy is “vibing” for product development. You can prototyping new features for existing products in plain english in a prompt or two.
It’s the first AI prototyping tool that captures your actual product from your browser — and generates prototypes that look exactly like what you’ll ship. And if you want changes? To test new elements? Try something else? Just tell Alloy the change you want to see it. It will show you.
Try it here.
It’s like Gamma but for making product prototypes and/or making mock-ups of changes to your live site.
It’s built specifically for Product Managers who are tired of frankensteining together screenshots in Figma or spending weeks with designers on concepts that never get validated.
Why Alloy Caught Our Attention
Most prototyping tools are either too simple (drag-and-drop builders that look nothing like your product) or too complex (engineering tools that require importing design systems and wrangling dependencies). Alloy solves the core problem every PM faces: how do you quickly test feature ideas without breaking your design system or burning designer time?
Here’s what makes it different:
Instant Product Capture: One-click browser extension captures any page of your existing web app. No screenshots, no manual recreation, no importing design systems. Just click “Capture page” and you’re prototyping in seconds.
AI That Understands Your Design System: This is the breakthrough. Alloy doesn’t just paste screenshots together like traditional tools. It understands your component library, design tokens, and patterns. When you prototype a new feature, it generates UI that looks like your designer made it — automatically.
Chat-to-Prototype Interface: Describe what you want to build in natural language. “Add a comment thread to this dashboard.” “Create an onboarding flow for new users.” “Redesign this settings page with dark mode.” The AI generates the prototype, maintaining perfect brand consistency.
3-5x More Detail Than Alternatives. And Getting Better.: According to their lab results, Alloy delivers significantly more detailed prototypes when starting from an existing product compared to alternatives like Lovable or other app builders. That’s the difference between a prototype you can actually show customers versus one where you’re making excuses for the design.
How Modern Product Teams Are Using Alloy (The Real-World Applications)
Since launching, Alloy has been adopted by product teams at companies solving the classic PM problems:
Problem 1: Customer requests that die in Linear tickets
Traditional flow: Customer asks for feature → PM creates ticket → Ticket sits in backlog → Stakeholders forget why they wanted it
Alloy flow: Customer request comes in → PM captures relevant product page → Prompts AI to build the requested feature → Shares link with customer for validation → Converts validated prototype to requirements
The win: PMs are turning customer feedback into visual prototypes in minutes instead of weeks. When you can show customers what their request would actually look like, you get much better validation before committing engineering resources.
Problem 2: Design bottlenecks blocking discovery
You know the pain. You want to test five different approaches to a feature, but each one requires designer time you don’t have. So you either:
- Wait weeks for designer availability (and lose momentum)
- Build the wrong thing because you couldn’t test alternatives
- Use generic mockup tools that confuse stakeholders
Alloy eliminates this bottleneck. PMs can now generate multiple on-brand variations instantly, validate with users, then bring the winner to designers for final polish. Designers get to focus on crafting the final experience instead of creating throwaway exploration work.
Problem 3: Prototypes that embarrass you in customer meetings
We’ve all been there. You’re demoing a prototype to customers, but it’s built in some generic tool with the wrong colors, wrong fonts, wrong patterns. You spend the first five minutes apologizing and saying “just imagine this looks like our actual product.”
Alloy prototypes look production-ready from day one. You can confidently share them with customers, executives, and teammates without disclaimers. The prototype respects your brand, your components, your design language.
The Integration Stack That Makes It Powerful
Alloy integrates with 30+ tools PMs already use, creating a complete workflow from insight to prototype:
- Linear, Jira, Product Discovery: Pull in feature requests and turn them directly into prototypes
- Slack, Intercom: Capture feedback from conversations and prototype solutions
- Notion, Confluence: Link prototypes directly to your product docs
- Dovetail: Turn customer research insights into testable concepts
The integration with Index (their main product planning tool) is particularly powerful: customer requests flow from feedback tools → get organized in Index → transform into Alloy prototypes → get shared for validation → convert to delivery tickets. It’s the complete PM workflow, finally connected.
What We Learned: The AI Prototyping Playbook for PMs
After analyzing how the top performing teams use Alloy, here’s what separates effective AI prototyping from just playing with new tools:
1. Capture Everything, Iterate Fast
The best teams capture multiple pages from their product right away. More pages = better AI understanding of your design system = more accurate results. Think of it like training the AI on your product’s DNA.
2. Start with Chat, Finish with Visual Editing
Prompting is perfect for generating initial concepts and making big changes. But switching to visual editing (Figma-style interface) is crucial for polishing final details. Top teams use both modes strategically.
3. Share Early, Share Often
Alloy makes sharing instant (just send a link). The teams seeing the most value are sharing prototypes constantly — with customers, teammates, executives — and iterating based on feedback in real-time.
4. Use Prototypes to Drive Alignment
The most effective use case isn’t just validating ideas with customers. It’s getting internal alignment. When everyone can see exactly what you’re proposing (not abstract requirements), decisions happen faster and with more conviction.
The Numbers That Matter
Based on early customer data and launch metrics:
- 10,000+ signups since launch, making it one of the most viral product launches of 2025
- 1 million+ impressions across product management communities
- Product leaders from Ramp, Uniswap, Clerk, and Semgrep in the user base
- Prototypes generated 3-5x faster compared to traditional design tools
- Minutes instead of weeks from idea to shareable prototype
For context: getting 10,000 signups for a PM tool in the first few months of launch is exceptional. Product management tools traditionally have slow, enterprise-driven adoption. Alloy’s viral growth indicates they’ve hit a genuine pain point.
The Founding Story (Why This Team Can Pull It Off)
Alloy comes from the team behind Index, a Y Combinator company (W23) that raised $3.5M from Blackbird and Bain Capital Ventures. The founders, Simon Kubica and Christian Iacullo, spent 5+ years at Atlassian and Canva respectively — meaning they lived the pain of product planning and prototyping at massive scale.
Simon was a product leader at Atlassian working on Jira, Forge, and new platforms. Christian was a software engineer at Canva during its rocket ship growth. Both saw firsthand how fragmented and painful the product development workflow had become.
They started with Index (product planning tool) and quickly realized prototyping was the massive gap. PMs could plan features in Index, but couldn’t quickly validate them without designer time or building off-brand mockups.
The Y Combinator pedigree matters here. YC companies have a 45% Series A success rate with median ARR of $1M+. The Index team launched with thousands of companies on their waitlist from top startups. They know how to build products that scale.
The Tech That Makes It Work
What Alloy is doing technically is genuinely hard. Here’s what’s happening under the hood:
- Browser extension captures not just screenshots, but the semantic structure of your UI
- AI models analyze your component library, design tokens, spacing systems, and patterns
- When you prompt for changes, the AI generates new UI using your actual components
- Results are rendered as interactive prototypes (not static images)
- Each new page you capture improves the AI’s understanding of your product
The code generation happens behind the scenes — users never see it — but that’s what enables truly interactive prototypes instead of clickable screenshots.
What Alloy Gets Right (And Where It’s Still Growing)
What They Nail:
- Setup is genuinely instant. No importing design systems, no configuration
- Quality of generated prototypes is remarkably good out of the gate
- The product feels fast and responsive (critical for creative workflows)
- Sharing prototypes is frictionless (just copy a link)
- Visual editing mode works well for fine-tuning
Room to Grow:
- Currently web-app focused (Figma capture coming but not ready yet)
- Can’t export code for now (intentional decision, but some teams want it)
- Best results come from capturing multiple pages first (small learning curve)
Alloy is the first tool purpose-built for the specific use case of prototyping new features for existing products as a PM.
How We Use Alloy at SaaStr (The Personal Test)
Like any tool we feature, we had to put Alloy through the real-world test ourselves. Here’s the specific workflow that made us believers:
I’ve been using Alloy to iterate on changes to pages I’ve built in Replit. The workflow is simple but powerful:
- Open the page I want to modify in my browser
- Capture it with Alloy’s browser extension
- Tell Alloy what changes I want (in plain English)
- Watch it make the design changes right there in the browser
- Take a screenshot and send it to Replie (my dev tool)
- Replit implements the changes
No more back-and-forth trying to explain what I want changed and why with Replit’s AI Agent. The visual prototype from Alloy becomes the perfect handoff spec. The developer can see exactly what I’m asking for, and I don’t have to write detailed requirements or mock things up manually.
This is the unlock: Alloy bridges the gap between product thinking and developer execution. Instead of writing specs or creating mockups in design tools, you prototype in context with your actual product, then use that prototype to communicate clearly with your dev team.
The Real SaaStr Take
Most prototyping tools try to replace designers. Alloy has a smarter thesis: accelerate the discovery phase so designers can focus on delivery.
The insight that makes this work is starting from your actual product instead of building from scratch. By capturing your real app, Alloy inherits all the design decisions already baked in. The AI doesn’t have to guess how your buttons should look or what your spacing system is — it already knows because it extracted it from your product.
This is the same pattern we saw with tools like Cursor (AI code editor that understands your codebase). The AI is dramatically more useful when it has context about what you’ve already built.
For Product Managers at any company with a web product, Alloy solves three critical problems:
- Validation bottleneck: Test ideas with customers before committing engineering time
- Design bottleneck: Generate on-brand prototypes without blocking designers
- Alignment problem: Show stakeholders exactly what you’re proposing, not abstract specs
After watching their launch momentum and using it ourselves, Alloy has the hallmarks of a breakout product: solving a genuine pain point, viral growth from practitioners, and a founding team with both the technical chops and product intuition to scale it.
Bottom line: Alloy is what AI prototyping should be — fast, on-brand, and built for the actual workflow of modern product teams. If you’re a PM spending time on prototypes, or constantly blocked waiting for design resources, this is worth trying.
The product is live now with hundreds of customers at leading tech companies. Based on their launch trajectory, customer traction, and the team’s track record, expect this to become essential infrastructure for product teams over the next 12-18 months.
Ready to see how AI can transform your prototyping workflow? Check out alloy.app or search for Alloy in the Chrome Web Store to install the browser extension.
This is part of SaaStr’s ongoing series highlighting AI applications that are actually changing how modern B2B teams work. Know an AI tool that’s crushing it? Drop us a line.
