Vibe coding tools like Lovable, Bolt, Replit, and Cursor let you ship in hours. The risk is that you can build something that works technically but doesn't make sense to the people you built it for. Validating with real users (five conversations, a clear question, a shared prototype) takes 3 to 5 days and tells you what no amount of AI-generated code ever will.
You built something fast. That's the whole point.
Lovable, Cursor, Bolt, Replit, these tools collapsed the time between "I have an idea" and "I have a working app" from months to days. What used to need a full engineering team now needs one focused founder and a good prompt.
But shipping fast isn't the same as shipping right.
The gap between "it works" and "it works for the people I built it for" is where most vibe-coded products run into trouble. You can have a technically solid app (clean UI, no bugs, fast) and still have built something your users don't understand, don't trust, or simply don't need in the way you imagined.
AI generates what you describe. If your description is based on assumptions about how users think about the problem, those assumptions get baked into the product. The navigation reflects your mental model. The terminology in the UI is your terminology. The workflow makes sense to you because you designed it.
The fix is simpler than you'd think. Five conversations with real users before you ship, 30 to 45 minutes each, one clear question driving the whole thing. No six-week discovery, no outside researcher. Just you and five people who'll actually use the thing.
Before you recruit anyone, write down one question this round of validation needs to answer.
Good examples: - "Can someone complete signup without asking for help?" - "Do people understand what the dashboard is telling them?" - "Would someone in [role] actually pay for this?" - "Are users finding the main feature, or going somewhere else first?"
Not useful: - "What do users think of the product?" - "Is this good?" - "General feedback"
Vague questions produce sessions where you talk about everything and learn nothing actionable. One question per round. You can always run another round.
Where you are in the build determines what you put in front of people.
Before you build: test a Figma prototype or clickable mockup. Find out if the concept and flow make sense before a single line of code gets written.
Mid-build: test a working prototype, even a rough one. Real interactions reveal things static screens never do. Users will try to click things you haven't built yet, which tells you exactly what they expect to exist.
Post-build, pre-launch: test the live product with people who had no part in building it. This is where most vibe-coded apps should land before any public release. You've committed to the build; there's still time to fix what matters.
Post-launch: test with real users hitting real problems. Support tickets tell you what broke. Watching actual sessions tells you why.
For most vibe-coded apps, post-build pre-launch is the highest-value window. You know the product works. You don't yet know if it works for someone who didn't build it.
Great Question supports both moderated and unmoderated prototype testing. Moderated means you're on a live video call watching the session in real time, which gives you more depth and lets you probe follow-up questions. Unmoderated is async: participants complete tasks on their own schedule, with screen and audio recorded, and you review the footage afterward. Unmoderated is faster to set up and scales to more participants without scheduling overhead. For early-stage validation, either works. For nuanced concept testing where you want to ask follow-ups, moderated gives you more.
This is where most builders stall. Here's where to look.
Your network. If you're building for a specific audience, you almost certainly know five people who fit. Ask directly. "I built something I'd love your honest reaction to, 30 minutes, I'll send you a coffee voucher." Most people say yes.
Your waitlist or beta list. These are your warmest recruits. They've already expressed interest. "We'd love to talk to you before we launch" converts well.
LinkedIn. Direct outreach to people with the right job title or context. One paragraph. What you built, why their perspective matters, what you're asking for (30 minutes), what they get (a $50 to $75 gift card).
An external research panel. If you need participants fast and your network doesn't have the right profile, Great Question's external recruitment panel gives you access to 6M+ verified B2B and B2C participants, filterable by role, industry, company size, and usage patterns. Qualified participants are typically available within 24 to 48 hours.
Before you invite anyone, write a quick screener: two or three questions that confirm they actually match your user profile. Testing with the wrong people produces misleading signal. You'll think something works when it only works for people who aren't your users. If you need a starting point, this guide to writing screener surveys walks through the basics.
First 5 minutes: their world, not yours
Ask about their work before you show them anything. What do they currently do in the area your product addresses? What's frustrating about it? This gives you baseline context and keeps your assumptions out of the conversation.
Next 20 to 30 minutes: watch them use it
Give them a task, not a tour. "You've just heard about this and you want to [specific goal]. Go ahead." Then stop talking.
Watch where they click first. Where they pause. Where they say "hmm." Where they give up. Whether the session is moderated (you're live on the call) or unmoderated (they're recording themselves async), the same principle applies: observe the behavior, don't explain the product.
The thing most builders get wrong here is the instinct to help. When a user struggles, every part of you wants to explain. Don't. If they can't figure it out, that's the data. Your explanation removes the signal.
In a moderated session in Great Question, you can use observer rooms to let a teammate watch the session live without the participant knowing. This is useful if your co-founder or a PM wants to see what's happening firsthand, without seven people on a Zoom making the participant nervous.
Last 5 to 10 minutes: follow-up questions
After the task, ask: - "Walk me through what you were thinking when you [specific moment]." - "What did you expect to happen when you clicked that?" - "If a friend asked what this does, what would you tell them?" - "What almost made you stop?"
These questions surface the reasoning behind what you observed. The behavior shows you what broke. The follow-up tells you why.
Right after each session, write down the two or three most important things you observed, one quote that captures something real, and what you'd change if you could change one thing today. Do this immediately. Notes taken an hour later are half as useful.
After five sessions, look at what shows up more than once. A problem appearing in three of five sessions is worth acting on. Something appearing once might be individual; note it, but don't redesign around it.
If you're using Great Question, AI analysis of session transcripts surfaces recurring themes automatically and links each one back to the specific participant quotes. What used to take an afternoon takes 30 minutes.
Five users is the right number for usability testing. But sometimes you're trying to answer a question that needs more signal: not "does this flow work?" but "how are 200 beta users actually experiencing this?"
Great Question's AI Moderated Interviews are built for exactly this. Rather than scheduling live 1:1 calls, an AI moderator conducts a structured conversation with each participant. It follows your discussion guide, probes on what each person says, and adapts to where the conversation goes, much the way a good human interviewer would. Each participant gets a real dialogue, not a static survey.
Instead of five to ten interviews, you can run 50 to 200 without proportionally more time on your end. Asana cut their research cycles from 2 weeks down to 2-3 days using AI moderated interviews. AI moderation surfaces 36% more unique themes across a participant set than human moderation alone, because it doesn't develop fatigue or unconsciously follow its own areas of interest. AI Moderated Interviews are currently in beta at Great Question. Join the waitlist to get early access.
Most vibe coding stacks look like this: build tool, deploy, maybe analytics. Nothing between "ship" and "find out it didn't work."
The validation layer sits between build and ship:
Build (Lovable / Cursor / Replit / Bolt)
↓
Validate (Great Question: prototype testing or AI Moderated Interviews)
↓
Synthesize findings (AI-powered, 30 minutes)
↓
Fix what matters
↓
Ship
Great Question's MCP integration connects directly to Claude, Cursor, and other AI tools. Right now, V1 gives you read access to your research repository: search studies, pull transcripts, surface highlights and insights, all without leaving your coding environment. Write access (triggering studies, managing participants) is coming soon.
The build took a day. The validation takes three. The return: you don't ship something your users can't use.
How many users do I need to test with before launching?
Five is the standard for usability testing. Research consistently shows that five participants catch around 85% of usability issues. For concept validation, eight to ten gives you more confidence in the pattern. If you're using AI Moderated Interviews to understand how a broader user base is experiencing the product, 50 to 200 is feasible and adds quantitative weight to your qualitative findings.
What if the people I need to test with are hard to find?
Great Question's external recruitment panel lets you filter by job title, industry, company size, seniority, and product usage. If you're building something for, say, operations managers at mid-size SaaS companies, you can recruit that exact profile instead of fishing through your personal network. Most searches turn up qualified participants within 24 to 48 hours.
Do I need a UX researcher to run validation sessions?
No. The methods in this guide (task-based usability testing, concept interviews, follow-up questions) are things any founder or PM can run without a research background. A researcher adds value for complex or strategic work. Pre-launch validation of a vibe-coded app doesn't require one. Great Question is designed so that product teams can run their own research with guardrails in place.
What's the difference between moderated and unmoderated prototype testing?
Moderated means you're on a live call with the participant while they use your product. You can ask follow-up questions in real time, which is useful for nuanced concept testing or when you want to probe unexpected behavior. Unmoderated is async: participants record themselves completing tasks, and you review the footage. Unmoderated is faster, scales to more participants, and works well for clear task-based testing. Great Question supports both methods.
What if users say they love it but don't actually use it after launch?
Trust behavior over stated preference. What someone does in a session is more predictive than what they say they'd do. "I'd definitely use this daily" from someone who struggled to complete a single task isn't reliable signal. The struggle is. When in doubt, watch what they do, not what they say.
Can I run validation inside Cursor or Claude without switching tools?
Yes. Great Question's MCP integration connects to Claude, Cursor, and other AI tools. V1 gives read access to your research data: studies, transcripts, highlights, and participant records. Write access (triggering studies, recruiting participants) is coming soon.
The best vibe-coded products aren't the ones built fastest. They're the ones built fast and tested with real people before anyone else saw them. Five users. One question. Three days. That's the layer your stack is missing.
See how Great Question works for product builders. Try prototype testing or book a demo.
Related: Prototype testing: the complete guide for product builders · How to test your Lovable app with real users · Great Question MCP for Cursor and Claude · AI Moderated Interviews
Tania Clarke is a B2B SaaS product marketer focused on using customer research and market insight to shape positioning, messaging, and go-to-market strategy.
