What Are Synthetic Users?

What does synthetic users mean?

A synthetic user is an AI-generated simulation of a human respondent, built from large language models trained on vast amounts of text, then shaped with specific demographic and behavioral parameters to represent a target audience. Nielsen Norman Group, a widely cited authority on usability research, frames synthetic users as virtual profiles generated from real data that function as customer simulators, using generative AI to analyze patterns and respond to interview-style questions, useful for desk research and generating hypotheses but explicitly not for final decision-making. The key limitation NN/g names directly: because synthetic users are derived from training data rather than lived experience, they lack the emotional nuance and contextual honesty genuine qualitative research requires.

The practical use case, then, is narrower than it might sound. Synthetic users are a stress test, not a substitute for talking to real people.

Why synthetic users matter for product managers

Builders Camp's Usability Testing for Product Managers bootcamp is directly connected to a masterclass built entirely around this technique: How to Stress-Test a Product With Synthetic Users Before It Touches Real Customers, delivered by Álvaro Ybáñez of OLX. The masterclass frames the value proposition clearly: testing with real users is slow, expensive, and risky, especially for products that touch real money, and synthetic user testing is an increasingly common technique in fintech, fraud detection, and agent-driven quality assurance to catch problems before they reach real customers.

For a PM, this matters because it offers a way to widen the range of scenarios tested before a costly or risky launch, simulating edge cases and adversarial behavior that would be slow or expensive to recruit real participants for.

How synthetic users are used in practice

The masterclass anchors its teaching in a real case: at OLX, Álvaro built a synthetic user testing system, generating fake users with varied behaviors specifically to stress-test a financing product before exposing it to real people. The session walks through the decisions that go into simulating realistic user behavior, what makes this hard to get right, and lessons from applying it to a high-stakes financial product, including what surprised him and what broke in the process.

That last part matters as much as the success: synthetic user testing at OLX was treated as a way to catch failures cheaply before real money and real customers were involved, not as a replacement for the customer research that followed.

How Builders Camp teaches synthetic users

Usability Testing for Product Managers builds the broader research discipline synthetic users sit inside, recruiting real participants, writing tasks that reveal behavior, and turning findings into prioritized fixes, and points to the OLX masterclass for the specific synthetic user technique as a complementary, earlier-stage tool. Builders Camp's Product Sense bootcamp reinforces the judgment call underneath this choice: knowing when a simulated signal is enough and when a decision genuinely needs a real person's response.

See AI-assisted prototyping for another way AI speeds up early validation, or responsible AI for the broader discipline of testing an AI-adjacent product before it reaches real users. See the Usability Testing for Product Managers bootcamp for the full curriculum.