Dear Readers,
Last month we covered 7 cheap(er) user testing tools for lean growth teams. But what if you could skip recruitment entirely?
That's not a hypothetical anymore. A growing wave of tools now let you simulate user feedback using AI. Synthetic personas that walk through your product, react in real time, and surface issues you'd normally need a research panel to catch.
This is a big topic, so we're splitting it into two parts. This week: we put one of these tools through its paces on our own site (and a community member did the same), then map the broader ecosystem of who's building what. Next week: a community member who built his own synthetic feedback system with Claude Code, plus we bring in the critics, because not everyone thinks this is a good idea.
Let's get into it.
~Scott Christensen
Founder @ Sendsight | GrowthDesigners Community Co-Lead
We Tried It on Ourselves
We'll be honest, our website at growthdesigners.co has had a layer of dust on it for a bit. So we figured we should eat our own cooking.
We ran Reforge's Synthetic User Testing against growthdesigners.co. They offer a trial run to get your feet wet. We simulated a first-time visitor who's new to growth design and wants to learn more and join the community. 12 sessions, 3 devices, done in 3 minutes, 60 insights generated.
We were pretty shocked at how good the recommendations were. The synthetic users flagged that we never define "growth design" above the fold, that our Slack join flow feels unnecessarily gated, that our newsletter subscribe form gives zero context on what you're signing up for, and that our School page buries pricing and curriculum below multiple CTAs. All fair. All things we're now actively fixing.
3 minutes, zero recruitment, and a real prioritized punch list. If nothing else, it's a great way to catch the obvious stuff before investing in a deeper study.
A Second Opinion: Mac Grossman's Trial Run
We connected with community member Mac Grossman, Director of Growth Design at Spring Health, who told us about his experience with synthetic testing. He ran a small landing page analysis using the plug-and-play personas and knocked it out in 30 minutes between meetings.
His verdict: "I'd expect similar results from UXR with a small batch of humans."
He did note some rough edges. The tool's URL scrubbing didn't load everything properly in the session replays, which created noise in the insights. But the signal was still there.
Mac’s next move: "I'd like to find an upcoming study to piggyback and compare real versus synthetic insights." That's the kind of head-to-head comparison we'd love to see more of in the community. If you've done something similar, drop it in the Slack. We'll feature it.
The Broader Market: Who's Building This?
Synthetic research is early but the ecosystem is growing fast. Here's how the landscape breaks down.
Synthetic UX Research
Tools that simulate users against your actual product flows.
Synthetic Users: Synthetic participants for interviews and surveys using multi-agent LLM architecture. Partners with Comcast NBCUniversal LIFT Labs.
Uxia: Barcelona-based tool for testing prototypes and flows, surfacing usability and accessibility issues. Still early stage.
Blok: Generates AI "virtual users modeled off actual product behavior" to stress-test onboarding flows and compare variants pre-launch.
Digital Twins & Synthetic Audiences
Simulated panels for market research and consumer insights.
Aaru: AI-powered prediction platform that simulates consumer behavior using synthetic audience agents. Just featured in the Wall Street Journal.
Simile: Digital twins built with real people, positioned as decision-making infrastructure for enterprise scenario planning.
Electric Twin: "Synthetic audiences" combining LLMs with social science research for message testing, product testing, and geo expansion.
Ditto: Census-grounded synthetic persona panels with published calibration methodology. Toronto-based.
AI-Moderated Research
Real human participants, but AI runs the interviews and synthesis.
Listen Labs: AI interviewer with automated study creation and recruitment from 30 million participants. Clients include Microsoft and Sweetgreen.
Outset: LLM-led interviews (video, audio, text) positioned as "depth of an interview, scale of a survey."
Coming Next Week
In part 2, we’ll feature how to get started doing your own synthetic user testing.
We’ll featuring a community member who built his own synthetic feedback system with Claude Code. We'll walk through how he did it.
Also, we’ll bring in the voices who think synthetic user testing is fundamentally flawed, and their arguments are worth hearing. Should be spicy! 🌶️
Stay tuned.
Scott Christensen is the co-founder of Sendsight, a product that automatically maps, audits, and improves lifecycle journeys across email and product.
He previously worked in growth design at Mercury and Expedia, and co-leads the GrowthDesigners.co community.
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