Watch simulated users find what you missed. Modeled on real customer personas, they explore the product, complete tasks, answer questions, and turn the experience into specific, prioritized feedback.
01/ 04
Choose who to simulate
Add your website, choose desktop or mobile, and select or describe a persona that reflects the customers you want to understand.
New test
Websitehttps://yourproduct.com
Device
Persona
First-time visitor
New to your product
Context
Followed a link from a friend. Has never heard of the product and will give it about a minute.
Goal
Work out what it does and whether it’s worth signing up.
Cares about
Clear valueLow effortNo surprises
02/ 04
Set tasks and questions
Give each user a goal, like completing site onboarding or selecting a subscription plan, and ask questions about clarity, trust, appeal, or anything else that matters.
Test plan
Task 1Starting on the homepage, and without signing up, work out what this product does and who it’s for.
Q1In one sentence, what does this product do?Open answer
Q2How clearly does the homepage say who it’s for?1–5 scale
Task 2Sign up and try the main feature. Stop wherever you would normally give up.
Q1Where did you first feel unsure what to do next?Open answer
Q2How likely would you be to come back tomorrow?1–5 scale
Task 1Find where to change your email notifications and turn off the weekly summary.
Q1How easy was it to find the setting?1–5 scale
Q2Did any label or icon mean something you didn’t expect?Open answer
Task 2Visit the dashboard, pricing, and help pages, then return to where you started.
Q1Did every page feel like part of the same product?Yes / No
Q2What drew your eye first on each page? Was it the right thing?Open answer
Task 1Halfway through the signup form, press Back, then Forward, and finish signing up.
Q1Was anything you had typed lost?Yes / No
Q2Did any error appear without saying how to fix it?Open answer
Task 2Submit the contact form twice in quick succession, then again with a 300-character name.
Q1Did anything save twice or fail without a message?Open answer
Q2Did you reach a page with no way forward?Yes / No
Task 1Create an account and complete every item on the setup checklist.
Q1How easy was setup overall?1–5 scale
Q2Which step felt unnecessary or unclear?Open answer
Task 2Upgrade to the Pro plan with test card 4242 4242 4242 4242.
Q1Did you complete the upgrade? If not, where did you stop?Open answer
Q2How clear was it what the upgrade unlocked?1–5 scale
Task 1On a phone-sized screen, open the menu and find the pricing for teams.
Q1Was any text or button cut off, overlapping, or hard to tap?Open answer
Q2How easy was the site to use with one thumb?1–5 scale
Task 2Fill in the booking form and submit it with the on-screen keyboard open.
Q1Did the keyboard ever hide a field or button you needed?Yes / No
Q2What was harder here than it would be on a laptop?Open answer
03/ 04
Review the findings
See whether the goal was completed, watch the recorded session, and get clear, reproducible findings with supporting evidence and recommendations.
Session recording
Example findings
CriticalReliability
The Pay button can create duplicate orders and charges.
After the first click, the Pay button stayed active with no confirmation that the order was processing. Clicking it again created two orders and charged the card twice.
Suggested fix
Disable the button and show a processing state after the first click, and make order creation idempotent.
Recording at 01:48 · 2 screenshots
04/ 04
Iterate swiftly
Apply the feedback and test again in minutes, without waiting for real users to give the right feedback or run into issues on their own.
Run history
CriticalHighMedium
Run 110:02 AM9 issues2 critical, 3 high, 4 medium
Run 210:47 AM4 issues1 high, 3 medium
Run 311:31 AM1 issue1 medium
Since run 1
Pay button disables after the first clickFixed
“Billed annually” shown beside the priceFixed
Continue stays above the mobile keyboardFixed
Plan comparison is hard to scan on mobileStill open
Rerun with the same persona and tasks →
Builder reactions
What builders said after Constants explored their products, surfaced the rough edges, and gave them something concrete to improve.
“This is incredibly valuable feedback. An outside perspective can really see things differently and more realistically.”
“This is pure gold. Amazing feedback. I’ll fix it.”
“Dang dude! This is quality feedback!”
“I have implemented these changes. I really appreciate it.”
“Your setup for this is pretty cool! Thanks for giving it a run.”
“You gave me a few new angles to look at. I’ll fix all of those in the next couple of days.”
“Thanks, I appreciate it!”
“They’re mostly API issues. We will work on it. I’m so grateful.”
“Thank you. That’s a lot of great feedback.”
“Amazed by how detailed the report is and how it covered most of the issues I have, including those that needed fixing.”
“These are all nice finds, and I’ll fix them today. I appreciate all your efforts.”
“This is incredibly valuable feedback. An outside perspective can really see things differently and more realistically.”
“This is pure gold. Amazing feedback. I’ll fix it.”
“Dang dude! This is quality feedback!”
“I have implemented these changes. I really appreciate it.”
“Your setup for this is pretty cool! Thanks for giving it a run.”
“You gave me a few new angles to look at. I’ll fix all of those in the next couple of days.”
“Thanks, I appreciate it!”
“They’re mostly API issues. We will work on it. I’m so grateful.”
“Thank you. That’s a lot of great feedback.”
“Amazed by how detailed the report is and how it covered most of the issues I have, including those that needed fixing.”
“These are all nice finds, and I’ll fix them today. I appreciate all your efforts.”
“Thank you. I will fix these now :-)”
“Incredibly appreciate the feedback. Thank you.”
“That is a genuine mistake and inconsistency I did not notice. I will fix it.”
“Thanks, will update!”
“Thanks a bunch!”
“Appreciate the signup attempts! I’ll take a look and see what the bug could be.”
“This is exactly the kind of feedback I was looking for. You caught several things I completely missed.”
“That’s some really honest and useful feedback. I’m impressed.”
“Thank you for such detailed and actionable feedback! I honestly didn’t consider accessibility at all, so this is great.”
“Thank you. I will fix these now :-)”
“Incredibly appreciate the feedback. Thank you.”
“That is a genuine mistake and inconsistency I did not notice. I will fix it.”
“Thanks, will update!”
“Thanks a bunch!”
“Appreciate the signup attempts! I’ll take a look and see what the bug could be.”
“This is exactly the kind of feedback I was looking for. You caught several things I completely missed.”
“That’s some really honest and useful feedback. I’m impressed.”
“Thank you for such detailed and actionable feedback! I honestly didn’t consider accessibility at all, so this is great.”
Pricing
Try a test for free.
Every workspace gets its first successful test free. No credit card required.
First test
Free
1 complete test Report and session recording included
Before Constants, we were product and engineering leads at Waymo. There, simulation modeled real human driving behavior at enormous scale, helping Waymo improve safety beyond human benchmarks and drive hundreds of millions of fully autonomous miles. We built the models and developer tools that made those simulations useful, repeatable, and accessible across the company.
Our mission at Constants
Give entrepreneurs, developers, and product teams the same leverage: simulation of real user behavior that surfaces problems sooner and helps them build better products faster.