Clean Sheets

The awkward question, solved. A free app that makes being tested the normal thing to be.

Flex Technologies Group Ltd · Bromley, UK · September 2026
Take the test. Check the text. Enjoy the sex.

1
Clean Sheets

Everyone knows they should ask. Almost nobody does.

The barrier to safer sex isn't the test. Tests are free, postal, ten minutes, results by text. The barrier is the conversation — and it happens at the worst possible moment.

"It felt like an accusation."
"I didn't want him to think I'd already decided."
"By the time it mattered, it was too late to ask."
2
Clean Sheets

The cost of not asking.

334,151new STI diagnoses in England in 2025. One every 95 seconds
119,033of them in 15 to 24 year olds. More than a third, every year
63,943gonorrhoea diagnoses, plus 8,262 of infectious syphilis
−9.4%chlamydia tests among under-25s, year on year. Testing fell faster than infections did

Source: UK Health Security Agency, sexually transmitted infections and screening for chlamydia in England, 2025 report, published 2 June 2026. Diagnoses fell 8.3% on 2024 while sexual health screens stayed flat at 2.36 million a year. Fewer tests, not fewer infections, is the risk.

3
Clean Sheets

Remove the conversation, not the test.

Public health has spent decades making testing easier. We make being tested visible — quietly, only to the people it matters to — so it becomes the socially rewarded state.

  • Nobody has to ask anybody anything.
  • Being tested becomes something the right person can see.
  • Not being tested becomes, gently, noticeable.
4
Clean Sheets

How it works.

1

Take the test.

Free postal kit or clinic. Upload the result. The app matches the name to your ID and the date to the calendar. That's your green tick, valid 90 days.

2

Check the text.

Type in your date's number. If they also hold a valid tick, you see it. If not, you see nothing — and nothing means nothing.

3

Enjoy the sex.

They never know you looked. No notification, no record, no conversation. Everybody has a better evening.

5
Clean Sheets

The rule that makes it spread.

You cannot look until you have been tested. That one rule puts a different pressure on each side, and neither side has to be persuaded of anything.

Her side: costs nothing.Checking is silent, free and leaves no trace, the same reflex as looking someone up on Instagram. The only price is having tested, which she was meaning to do anyway.
His side: can't be checked, can't be asked.He can't know whether she'll look, can't ask, and can't know what she'll think if she finds nothing. He only knows the app exists. Risk-averse brains fill the gap. He orders a kit.
Nobody talks about it.The app never notifies, never announces, never shows a miss as anything but nothing. The pressure stays invisible, which is why it works.
Testing becomes the default.Every 90 days, without a campaign or a leaflet. Not wearing the seat belt becomes the odd thing.

Behavioural design, not education. Persuasion has never got people to eat well, exercise or test. A quiet mechanism that makes the tested state the norm can.

6
Clean Sheets

Privacy isn't a feature. It's the product.

  • Your number is kept once, for signing in, and never shown to anyone. Everywhere else it is a one-way hash.
  • Looking someone up writes nothing. There is no record of who checked whom, anywhere, ever.
  • Every "no" looks identical: not on the app, not tested, expired, blocked, or positive. Same response, same timing.
  • A positive result is never shown to anyone, including as a red cross. It simply produces no tick.
  • Result and ID photos are deleted the moment they're checked. Only "tested on this date, this panel" survives.
  • Block anyone. Or go invite-only. Neither list is visible to the people on it.
  • Delete everything in one tap. No analytics, no ads, no third-party scripts.
7
Clean Sheets

Who it's for.

Her, first.

Women aged 18–30 who date on apps. They carry the anxiety and the consequences, and they tell each other everything. They're the ones who send it to the group chat.

Him, through her.

He downloads it because he heard she might look him up. Social pressure does the public-health work that leaflets never managed.

Not a dating app.

It doesn't match anyone. It sits between the dating app and the bedroom, and it's the only thing that lives there.

Not a medical service.

It doesn't test anyone. It sends people to the free services that already exist and makes using them worth it.

8
Clean Sheets

What it does for the health system.

Demand for existing services.

Every tick starts with a free NHS-commissioned test. The app is a referral engine to SH:24, Sexual Health London and local clinics — not a competitor to them.

Repeat testing, by design.

Ticks expire at 90 days. The incentive to retest is social, personal and permanent. No reminder campaign required.

Earlier detection, less onward transmission.

More people tested more often among the 18–30s who account for the largest share of new diagnoses.

Measurable, without surveillance.

Aggregate only: ticks issued, retest rate, referral clicks by region. No individual data leaves the app. Ever.

9
Clean Sheets

What people say first. And the answer.

"Just show them your test."

Yes. Nobody gets one and nobody shows one, which is why it hasn't moved anything. The screenshot is the incumbent. Our only advantage over it is that nobody has to ask.

"That's shady."

It sounds like surveillance and is built to be the opposite: a lookup writes nothing, notifies nobody, and every miss looks identical. The engineering makes it false. Our copy has to make it obviously false.

"It's not a guarantee."

Correct, and we say so everywhere. Window periods exist and people have sex after they test. The alternative on offer is "yeah, calm". Not perfect versus perfect. Better versus nothing.

"Nobody I know would do this."

Nobody wants a seat belt either. The first reaction from someone who doesn't feel the problem is always "who's this for". The mechanism doesn't need them to want it. It needs one place where enough people have ticks.

Verbatim from the first young person to see it, 16 September 2026, logged in full in our feedback file. We'd rather quote the objection than pretend it won't come.

10
Clean Sheets

One place first.

A check that finds nothing three times gets deleted. So we don't launch to the country. We reach density in one bounded community, then let the mechanism do the rest.

What "one place" means

A single university, a London borough, or one festival crowd. Somewhere people date each other, talk to each other, and share a testing service we can partner with.

What density takes

Enough ticks that an early check lands on one. Kits handed out with the partner service, a launch week timed to term or the event, and the youth panel's own group chats as the first seed.

What we measure

Ticks issued, checks that found one, retest at 90 days, and referral clicks into the partner's service. Aggregate only, published either way.

Candidates: a South London university with an SH:24 or SHL contract in its borough; Bromley, our home borough, with its own online-testing provider; one summer festival with an on-site testing charity. The pilot partner chooses. We bring the kits and the measurement.

11
Clean Sheets

Free. And staying free.

It only works if everyone's on it, and everyone isn't on anything that costs money. No ads, no data sales, no premium tier. Not now, not later.

What it costs to run

Pennies per user per year. Serverless, no staff-heavy operations, no lab.

How it's funded

Grants and foundations, health-service partnerships, sponsored test kits.

What we'll never do

Sell data. Show ads. Charge the people we're trying to protect.

12
Clean Sheets

Partner with us.

Testing services & kit providers

Replace the photo upload with a verified result handed straight from your system — a reference number, not a screenshot. Co-branded kits. A new front door for the hardest-to-reach age group.

ICBs, trusts & public health teams

A 12-month regional pilot: launch, measure referral uplift and retest rates, publish what we find, good or bad.

Charities & foundations

Co-design with the young people you already reach. Funding that keeps it free and independent.

Researchers

Behavioural and epidemiological evaluation on aggregate, anonymised data. We want to know if it works as much as you do.

13
Clean Sheets

Where we are.

Built and live

Phone sign-in, tick issuance with AI reading plus human review, private lookups, block and invite-only lists, one-tap deletion, PWA on iOS and Android.

Provider directory

196 verified testing services in 36 countries: free and paid home kits, clinic finders, charities and NHS services, grouped by region. 59 across the UK alone, every link checked.

Next

Verified results direct from partner labs. SMS notices. More countries and languages. An independent evaluation.

What we need

A clinical partner, an evaluation partner, and funding for the first regional pilot.

14
Clean Sheets

Who's behind it.

Jos, founder

Seventeen years across policy research, fintech, public policy and consultancy. Builds with AI agents through Flex Technologies Group, which means a working product ships in days, not quarters — and iterates at the speed of feedback.

Who we're looking for

A clinical advisor in sexual health. A behavioural-science advisor. A young people's advisory group who'll tell us, bluntly, what's wrong with it.

15
Clean Sheets

The ask.

Pilot funding

Twelve months, one region, evaluated. Enough to cover kits for early adopters, an evaluation partner and one full-time person.

A verified-results partner

One testing service willing to hand results to the app by reference number, so nobody ever has to photograph anything.

An evaluation partner

A university or public health team to measure referral uplift, retest rates and what young people actually think of it.

Flex Technologies Group Ltd, trading as Clean Sheets · Company number 15882806, registered in England and Wales · 850 Green Lanes, London N21 2RS
Contact: admin@flexgroup.dev · Working app and deck: cleansheets.fyi/about · One page: one-pager.pdf

16
Clean Sheets

Everyone wants to have fun. Nobody wants to kill the vibe.

Everyone wants to have sex. Nobody wants to talk about it in the toilets of a club at one in the morning. This fixes that, for everyone, and all anybody has to do is look after themselves.

Take the test. Check the text. Enjoy the sex.

17
Download PDF (A4)