You buy the engine at 50p per device per month. Then you decide what it is. Child safety for parents. Endpoint monitoring for a call centre. Driver checks for a haulage firm. You write the rules, you name the product, you set the price — and every customer pays you again next month whether you worked or not.
Your cost
50p
Your price
£4.50
Your margin
£4.00
01 · Run it like a business
Not a wage. A book of revenue.
Forget how much you make this month. The question a businessman asks is what the whole thing is worth in three years. Set how many customers you can add each month and what you charge them — the graph stacks it up, because last month's customers are still paying.
New devices you add each month25
Not total — new ones per month. Five is a slow start. Fifty means you're working at it.
Your price per device, per month£4.50
Your market, your price, your currency. We take 50p of it and nothing else.
Customers who stay each month97%
Nobody keeps everyone. 97% means three in every hundred leave each month — normal for a consumer subscription, and the number your buyer will ask for.
Monthly margin, three years out
Your marginOur 50p
Month 12 margin
£0
per month
Month 36 margin
£0
per month
Devices by month 36
0
all still paying
Earned over 3 years
£0
cumulative
What the book itself is worth by year three
£0
Recurring-revenue businesses typically change hands at somewhere around 2–4× annual revenue, depending on churn and how much of it depends on you personally. This is the middle of that range on your own numbers — an illustration, not a valuation.
02 · The climb
It starts at ten devices.
Every rung at the price you just set. The first takes an afternoon. Every one after is the same conversation again.
The bit people miss: a job pays you once for the hour you worked. Every device you sign up pays you again next month, and the month after, while you're asleep or out signing up the next one. Ten new customers a month isn't ten customers — by December it's a hundred and twenty, all still paying.
03 · Why this and not the other stuff
You've seen the dropshipping adverts.
The honest comparison, including the part that's harder here.
Flipping products
Paid once. Then back to zero next month.
Someone always undercuts you. Margins die.
Capital up front on stock or ads before a penny comes back.
Returns, shipping, customs, angry customers.
You can't sell the business. There isn't one.
Nobody's life is better because you sold it.
This
Paid every month, for as long as they keep it.
Your cost is fixed at 50p and doesn't rise as you grow.
No capital. No stock, no fee, no minimum.
No shipping, no returns, no warehouse. It's software.
A book of subscriptions is an asset you can sell.
Harder to sell than a phone case — you have to explain it.
04 · What they get for the money
Three things on the phone itself.
Each has the exact sentence to use. Nick them word for word — they're written to be said out loud.
Guardian
Child protection
Spots the patterns that come before harm.
Watches for known warning signs of grooming — pushing for secrecy, isolating a child, moving them to a private chat — and tells the parent. The messages are never stored, only a fingerprint. What is kept is sealed, so it can't be edited later and it means something to a school or the police.
Say this
“Your kid's phone tells you when something starts going wrong — without you having to read their messages.”
Sentinel
Fraud alarm
Catches it during, not on the statement.
Watches speed and pattern — a run of login attempts, a burst of payments, the account surfacing in another country minutes after the last one. Classic takeover signals. Flags them live and seals the evidence, so there's something real to show the bank.
Say this
“When someone tries to get into your account, you find out while it's happening.”
Sebdog
It runs on the phone
Not on our computers. Theirs.
The engine sits on the device itself, so their data doesn't have to leave it to be protected. No round trip, nobody in the middle. Businesses pay serious money for this as an on-site product. Here it's part of the package.
Say this
“It protects you without sending your life to somebody else's computer.”
The proof layer
All of it, sealed
A record nobody can rewrite — us included.
Every alert is written into a chain where each record is locked to the one before, so altering anything past visibly breaks it. That's what turns an alert into evidence rather than a screenshot somebody could have faked.
Say this
“If it happened, you can prove it happened.”
05 · The part that makes you a company
Signal Packs — your product, not ours.
Here's what you're really buying, and it isn't a child-safety app. The engine watches events on a device, scores them against a set of rules somebody wrote, and seals the result so it can't be altered afterwards. Guardian is just one set of rules. A Signal Pack is you writing your own set — and the moment you do, it stops being our product and starts being yours.
You define what's risky
Not us. You decide what the engine watches for and what it does about it. Same engine, completely different product.
You name it and brand it
Your product name, your logo, your pricing page. Your customers never need to hear of us.
One pack, sold a thousand times
Write it once for a market you understand, then sell that same pack to every firm in that market. That's a product line, not a side hustle.
Different packs, different prices
A parent pays £4. A call centre pays £12 a seat for the same engine with different rules and a sealed audit trail.
And the churn angle: a customer who has helped shape their own pack does not cancel in month three. Churn is the single number that decides what your book is worth — every point of it you avoid raises the sale price of the whole business.
Be straight about the boundary: the engine works on the signals it can actually see on a device — patterns, timing, addresses, activity. A Signal Pack decides what to do with those signals. It is a rules-and-evidence layer, not magic, and you'll sell far more of it by telling a buyer exactly what it watches than by implying it watches everything.
Twenty packs are already written.
You don't have to start from a blank page. There is an open library of packs at sebbi.pro/packs.html — legal review, clinical summarisation, support triage, coding agents, security operations, public sector correspondence. Open any of them, read every rule and the reason it exists, and fork it into your own name in one tap.
Free to read, free to publish
No account, no key, no card. Writing a pack and putting it in the library costs nothing and never will.
Publishing proves it's yours
The moment you publish, the pack's fingerprint is sealed into the chain with the date. If somebody copies your work later, the record already says who wrote it first — including against us.
Fork the closest one
Find the pack nearest to your market, disagree with its thresholds, change them, publish yours. The parent is recorded, so the lineage is visible rather than argued about.
Running it needs the engine
This is the bit that pays you. A pack on its own is a text file — it decides nothing and produces no evidence. Every person who wants to actually run your pack needs a device on the engine, and that's your 50p.
Why this matters to your book: a pack you wrote and published, with your name sealed on it, is an asset you own outright. Write one for a market you understand and it can be sold to every firm in that market — and every one of them arrives at the engine to run it.
Every one of these is the same engine at the same cost to you. The only thing that changes is the pack you write and the price you charge. Pick the market you already understand — the one where you know how people talk.
Consumer
Parents
The easiest first sale you'll ever make.
Grooming warning signs, sealed alerts, rules the parent sets. Sell it at £4–£6 a month. Low price, huge market, and the referrals do the work — parents talk to other parents about exactly this.
Business
Call centres
Hundreds of seats in one signature.
Every agent's endpoint monitored against your pack, every flag sealed into a record a compliance manager can produce later. £8–£15 a seat. One five-hundred-seat floor is more revenue than two hundred parents, from one meeting.
Business
Any firm with endpoints
Laptops, tablets, handsets, kiosks.
Write a pack for their policy — what's normal on a company device and what isn't — and sell it as monitored-with-evidence. £5–£12 a device. Two hundred devices is a real contract with one invoice.
Vertical
Care & support agencies
Lone workers, vulnerable clients.
A pack built around visits, hours and unusual activity, with a sealed trail for safeguarding. £8–£20 a device. They already have the duty; nobody's sold them the evidence layer for it.
Vertical
Haulage, taxi, delivery
Drivers, handsets, disputes.
Your pack, their fleet, and a record that settles an argument about what happened and when. £5–£10 a driver. One firm with sixty drivers is £400 a month from a single phone call.
Vertical
Schools & youth clubs
One conversation, a hundred families.
Sell to the institution, deploy across the families. £3–£5 a device at volume, one invoice, one relationship to maintain, and a safeguarding lead who wants the evidence trail anyway.
The move nobody makes: don't sell all seven. Pick one, write one really good pack, and go and own that market. The firm that becomes "the endpoint evidence people for care agencies" charges four times what a generalist charges, and sells the business for more at the end because the book is concentrated and defensible.
07 · Scale past yourself
Your book. Your sales force.
There's a ceiling on what one person can sell, and it's about five hundred devices. Past that you stop selling and start running something.
Put people on it
Your cost stays at 50p no matter who made the sale.
Pay a seller commission out of your margin — at £4.50 there's room for both of you.
Give them the scripts on this page. They're written to be read out.
A pack you already wrote means a new seller needs no product knowledge, just the conversation.
Recurring revenue means their sale keeps paying you long after their commission is spent.
Or put a machine on it
An existing call centre can sell this tomorrow, off a script, into their existing list.
A phone shop chain adds it at the counter across every branch.
An IT firm adds one line to invoices clients already pay monthly.
Any business with a customer list already owns the expensive part — the customers.
You keep every penny above 50p on all of it.
The honest maths on hiring: at £4.50 you keep £4. Give a seller £1 per device per month and you still hold £3, on a sale you didn't make. Ten sellers doing twenty a month each is 200 devices a month landing on a book you own. That's the difference between a wage and a company.
08 · Your first ten customers
You already know every one of them.
No adverts, no website, no capital. Ten people who trust you and have kids with phones. Here are the words.
The school gate
In person · 30 seconds
“Can I ask you something daft — has your lad got a phone yet? Right. So I've started doing something that puts a thing on it that watches for the grooming stuff. It doesn't read his messages, it just tells you if someone starts asking him to keep secrets or move to a private chat. It's a fiver a month. Want me to put it on for you?”
Why it works: you named the fear, killed the objection they were about to make, and gave the price before they had to ask. Say the price. People who hide the price never sell anything.
The group chat
WhatsApp · paste it
“Bit random. I've started doing a thing for kids' phones — it watches for the grooming warning signs and tells the parent, without reading their messages. Also catches someone trying to get into your bank. £4.50 a month, cancel whenever. If anyone wants it on their kid's phone give me a shout.”
Why it works: no link, no sales voice, no pressure. In a group of forty parents you'll get three — and those three tell other parents, because this is the thing parents actually talk about.
The counter
If you sell or fix phones
“Is this one for yourself or one of the kids? For your daughter — right. Do you want me to put the safety package on before you go? It watches for grooming and tells you, and flags anyone trying to get into her accounts. Five pound a month and I'll set it up now while you're stood here.”
Why it works: they're already spending and already thinking about their kid. Every handset becomes years of monthly revenue instead of one margin you spend that week.
The business call
Clubs · schools · employers
“I supply a safety package for phones — it flags grooming warning signs to a parent and keeps a sealed record you could hand to the police if it came to it. I'm offering it to your families at £4 a month. Could I show you what a parent actually sees? Five minutes.”
Why it works: one club is a hundred families in one conversation. That's £350 a month from a single phone call. Ask for the five minutes, not the sale.
The only rule: ask for the money. Nine out of ten people who fail at this never say a price out loud. Say it plainly, then stop talking and let them answer.
09 · How the good ones sell it
Never oversell this one thing.
Left column is true and provable. Right column is a promise nobody on earth can keep, us included. The left closes better anyway — people trust the seller who tells them what it can't do.
True. Say it freely.
Flags known warning signs of grooming and alerts the parent
Never stores the messages — only a fingerprint
Keeps a sealed record nobody can quietly change later
Anything hinting a parent can stop paying attention
Why we're hard on this: it catches known patterns. It cannot catch every clever rewording and no honest product claims otherwise. What it guarantees is the record. A parent promised a wall who got a smoke alarm cancels, tells forty other parents, and takes your book with them. Sell it straight and they stay for years. Overclaim on child safety and your code gets pulled.
10 · Start
Get your reseller code
Free. No fee, no minimum, no contract, no card. You get your code and your key on this page in about ten seconds — then go and ask the first ten people you know.
Your reseller code — every device signed up with this is yours
—
Your API key — save this somewhere safe
—
Next three things, in order:
1. Save that key somewhere you won't lose it.
2. Decide your price and stick to it for the first month.
3. Use the school gate script on five people today. Not tomorrow.
11 · Straight answers
What everyone asks first.
Do I need money to start?
No. Not a penny. No joining fee, no stock, no minimum, no card. You pay 50p only for devices that are actually live — and by then your customer has already paid you.
Do I need to be technical?
No. You get a code, they install it, that's it. If you can set up a phone for somebody, you can do this.
Do I need a company?
Not to start. But once money's coming in, tell HMRC — this income is taxable like any other, and registering as a sole trader is free and takes ten minutes online. Don't skip it.
Is this one of them pyramid things?
No, and here's the test. You don't recruit anybody. You don't earn from other sellers. You don't buy in and there's nothing to buy. You sell a real product to real people who use it, and you pay 50p per device. If a scheme's money comes from recruiting rather than selling, walk away — this one passes that test.
Can I really sell the business later?
A book of live subscriptions is a real asset and people do buy them. What it fetches depends on churn, how many customers depend on you personally, and whether your records are clean. Nobody can promise you a buyer — but unlike flipping products, there's something there to sell.
Can I sell outside the UK?
Yes, anywhere. Your currency, your price, your language. The 50p stays in sterling, so in plenty of markets the margin is better, not worse.
What if a customer cancels?
Billing stops for that device — your bit and our bit. No penalty, no clawback, no notice period. Your other customers are untouched.
Will you go behind my back to my customers?
No. You invoice them, you hold the relationship, and their devices are tied to your code permanently. If your ten become ten thousand, that's yours.
How do I know any of this is real?
Don't take our word for it. The chain is public, the checking routes need no account, and the verifier runs on your own machine with the internet off. You're meant to check rather than trust. Start at the whitepaper.
Honestly — month one?
Ten to thirty devices if you actually ask everyone you know. At £4.50 that's £40 to £120 a month — still arriving next January, and the January after. Anyone promising you thousands in week one is lying to you.
About the numbers: every figure comes from sliders you set yourself. It's arithmetic, not a forecast, and nobody is promising you customers or income. The valuation figure is an illustration using a common market range for recurring-revenue businesses — it is not an offer, an appraisal, or a guarantee that anyone will buy your book. What we promise is the price: 50p per active device per month and nothing else.
About the product: sealing proves something happened in a particular form at a particular time and hasn't changed since. It does not prove the contents are true and it does not discharge anybody's legal duties. Guardian is a safeguarding aid and an evidence layer. It supports a parent. It never replaces one.