How it works

How Plastic's synthetic user research works

Plastic runs synthetic focus groups. You build AI personas that know what real people in their position would know, and nothing more. They react to your materials, answer your questions, and produce a structured report with charts, quotes, and recommendations.

Most teams use it to get early signal before a live study, stress-test materials before they ship, or check assumptions when scheduling real participants isn't practical.

How it works, step by step

1. Build personas with real depth

Each persona has a full profile: who they are, how they think, what they do for work, what frustrates them, and what they know and don't know. A logistics manager won't give you marketing advice. A first-time founder won't talk about enterprise procurement. These boundaries keep responses grounded in what each persona would realistically say.

You can create a persona in two ways. If you want full control, write a Custom Persona from scratch. If you want a faster starting point, use Plastic Wizard: give it a short description of the kind of person you need, and it builds a reusable persona in about five minutes that is shared with the community, scores its realism from 0 to 10, and asks follow-up questions until the profile feels solid.

2. Upload what you want to test

Bring whatever you'd bring to a real focus group: landing pages, pricing tables, onboarding screenshots, pitch decks, ad mockups, tweets, survey drafts. You can upload images, text documents, or PDFs (automatically converted to images). Personas see and react to the same things your audience would.

3. Ask your research questions

Write what you'd ask in a live session: "What's your first impression?", "Would you pay for this?", "What's confusing?" Each persona answers on their own, in character, based on their background and how they're feeling that day.

That last part matters. Plastic picks from 17 mood states for each response. One persona might be relaxed and chatty, another stressed and short. If someone would be impatient with your question on a bad day, you'll see that too.

4. Read the report

Every session runs two analyses at once: one for numbers, one for meaning.

You get a summary with up to five ranked findings, three concrete next steps, and the top three direct quotes with context. Each question gets its own breakdown. Scale questions ("How likely would you…") get automatic score distributions. Category questions ("What features matter most?") get grouped charts. Open-ended questions get theme summaries.

The report also flags fit. If a persona isn't your target buyer, the analysis calls that out so you can weigh their responses accordingly.

5. Clone, change, rerun

Changed the headline? Reworked the pricing? Clone the session, swap the materials, and rerun. The original stays frozen so you can compare results side by side.

What you can test

  • Positioning and messaging. Does your value prop land with your ideal buyer, or do they shrug while a different segment lights up?
  • Landing pages and copy. Upload the screenshot, ask five personas for first impressions, see which version wins.
  • Pricing and packaging. Is your pricing clear? Does the free tier feel generous or cheap? Personas with different budgets give you different answers.
  • Onboarding flows. Walk personas through your first-run screens. Find the step where a non-technical user says "I have no idea what this means."
  • Feature concepts. Before you build it, describe it. Ask: would you use this? How often? What would you pay?
  • Pitch decks. Build a panel of synthetic investors and run your deck past them. Find out which slides lose attention and where the hard questions come.
  • Tweets and social posts. Test a draft post against the audience you actually want to reach. See if the reaction matches your intent before you publish.
  • Survey and interview questions. Run your draft questions on synthetic participants first. If a persona misreads the question, real ones will too.
  • Ad creative. Test angles across segments. Does the urgency hook work on enterprise buyers, or only on indie hackers?
  • Competitive positioning. Ask personas who use a competitor how they'd evaluate your alternative. They respond based on what they'd realistically know about both products.
  • Internal memos and announcements. Run a reorg announcement past synthetic employees before sending it. See where people get confused or anxious.

Best for

  • Product managers who need user signal before committing engineering time
  • Founders moving too fast for a two-week research cycle
  • Marketers testing messaging across audience segments in the same afternoon
  • UX researchers pressure-testing study designs before spending the live budget
  • Agencies delivering consumer insight on tight timelines without fielding a panel
  • Anyone preparing a high-stakes piece of communication and wanting a gut check first

Not ideal for

  • Usability testing with interactive prototypes and click tracking
  • Research that needs participants' real purchase history or account data
  • Regulated contexts that require human-subjects review board approval
  • Replacing qualitative research entirely. Plastic is a fast directional tool, and works best alongside real studies

Frequently asked questions

How realistic are the persona responses?
Every persona stays in character and respects what someone in their position would actually know. A logistics manager won't offer opinions on UX design. Responses come in natural, spoken-word style, with hesitation, bluntness, or boredom when the question doesn't land. Plastic picks from 17 mood states per session, so responses include impatience, distraction, and skepticism alongside enthusiasm. No single persona will match a specific real person, but they reliably surface the same objections, confusion, and preferences that live research does.
Can I customize the personas?
Yes, but there are two modes. Plastic Wizard is designed for minimal input from you and creates reusable personas that are shared with the community. Custom Personas, available on Team and Researcher plans, give you full control over the entire persona description and stay private to your account.
How many personas can I include in a session?
Depends on your plan. Every plan supports multiple personas per session. They all respond at the same time, so more personas doesn't mean more waiting.
What file types can I upload?
Images (JPG, PNG, GIF, WEBP), text files (TXT, Markdown), and PDFs (up to 20 pages, auto-converted to images). Most teams upload screenshots, mockups, PDFs, or paste in copy they want reactions to.
Is my data private?
Your session materials, answers, and results stay private to your account. Custom Personas do too: they are available on Team and Researcher plans, give you full control over the full persona description, and are never shared outside your account. Plastic Wizard personas work differently: they are designed to be easy to create, reusable, and shared with the community. You can also create a share link for any finished session; it shows a read-only report and hides your raw materials, individual answers, and account details, and you can revoke it anytime.
How is this different from just prompting ChatGPT?
ChatGPT gives you one voice. Plastic gives each persona their own identity, their own knowledge limits, and their own mood, with built-in rules that stop them from just agreeing with you. Sessions are repeatable: same personas, same questions, different materials, so you can isolate what actually changed. The output is a report with score distributions, ranked findings, direct quotes, and per-question analysis you can export or share.
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