Built4U Apps · Chennai, India Two products · One rule
We keep the record. Never the valuable.
We build private records of the things families avoid putting in writing — what you own and where it is kept, and money lent between people who trust each other. In both, we hold the account of the thing. We never hold the thing itself.
See what we've built What we refuse to build KinNest — early access ↗
What we do
A record, kept carefully, for the day it is needed
Most homes have one person who knows where everything is. The policy taken out in 1998, the locker and which bank it belongs to, the papers for the land, the money a cousin is still repaying. Everyone else knows roughly.
When that person is suddenly not there, roughly turns into months of paperwork at the worst possible time — and sometimes into nothing at all, because nobody knew the thing existed to go and claim it.
That is the problem this company works on. Not wealth, not planning, not advice. The plain record: written by the person who knows, readable by the people who will need it, on the day they need it and not one day before.
The discipline that defines us is what we refuse to hold. Keeping the map and not the keys puts a ceiling on what our worst day can cost the people who trust us, and it is the only version of this promise that can be kept for decades rather than for as long as a security team lasts.
We do not build software for other companies. We build the products we ourselves needed.
In our own words
Both of these started at home. The same scattered accounts, the same one person who knows where everything is, the same loan nobody had written down — and the same uncomfortable realisation that if that person were not around tomorrow, the rest of us would be guessing.
So we build as our own first customer. Every product here answers a question from inside our own house before it is offered to anyone else. The person it is built for is a specific, real, non-technical person — not a persona — and it is not finished until that person can use it on their own, without being taught.
That is why these products are plain rather than clever, and why the list of things we have refused to build is longer than the list of features.
No. 01 Product
KinNest
Early access · closed testingA private record of what you own and where it is kept — so the people you name can reach it on the day it is needed, and not one day earlier.
It is a map, not a vault. It is built for pointers: the last four digits of a policy number, the cupboard the sale deed is in, the bank the locker belongs to. We never ask for a password, we do not ask you to upload documents in place of the originals, we do not record what anything is worth, and there is no connection to your bank.
Secrets belong somewhere built for them — a password manager, a bank locker, a sealed envelope, a notebook. Not here. If it looks like you are typing one in, the app says so at that moment.
The point of designing it that way: what we are asked to hold is a map. Even in the worst case, a map shows a family what exists and where to go — it is not a set of keys.
30-day free trial · one plan, everything in it
No payment is being taken during testing.
What we never ask for
- Passwords, PINs or authenticator codes — we warn you if you start to
- Your documents, in place of the originals
- What anything is worth
- Any connection to your bank
- What you own, and where it is kept
- The people you name, and what they may see
- A note in your own words, for them
How the handover works
One tap from you cancels it from any stage. The mechanism is built to fail toward “the owner is alive”, and the decision is made on our servers — never on a phone, so a lost or wiped handset changes nothing.
No. 02 Product · In development
LendBook
In developmentA private record of loans personally given and taken — the money that moves between family, friends and a small shop's regular customers, which no bank ever sees and nobody likes to write down. It records the loan. It never lends or moves money.
It is in development, and it is not released yet. KinNest is the nearer of the two to a real launch and has our attention first.
That order is deliberate. We would rather finish one product properly than ship two halfway — and the discipline that comes from putting a product in front of the person it was built for, early, is the one we now apply to both.
How we build
Five principles, and what each one costs us
A principle nobody pays for is not a principle. Each of these forfeits something real.
We are our own first customer.
Every product answers a question from inside our own house before it is offered to anyone. The reference user is a specific, real, non-technical person, and nothing ships until we have answered whether they could use it unaided. So the products are plain rather than clever, and anything that fails that test waits — however good it looks in a demo.
We keep the record, never the valuable.
KinNest never asks for a password, a PIN or an authenticator code, nudges account numbers down to their last four digits, and warns you at the moment it looks like you are entering a secret. We tell people plainly to keep those somewhere built for them instead. It records no values and connects to no bank; LendBook records a loan and moves no money. So we cannot recover a password for you — we never asked for one — and a family still has to go to the institution with the paperwork. We only make sure they know which institution, and where the paperwork is.
What we refuse is the product.
No will generation — that is a lawyer's instrument, not ours. No asset-recovery or claim-filing service. No net-worth totals, because a list of values is a shopping list for whoever gets hold of it, and a family needs to find things, not price them. No visibility for anyone, including a spouse, before the day it is needed. Several of those refusals are the obvious ways to make more money from the same customers.
We say the part that is not true yet.
KinNest's own security page states the limit of its security claim: today our systems can reach a record, so “we do not read it” is the honest verb and “we cannot” would not be. We have committed not to launch widely until end-to-end encryption is true, and to say so on the day it is true and not one day before. That hands anyone who wants it a sentence to use against us, years before we have to.
A subscription is the whole business model.
No investors, no advertising, and nothing about a person sold or brokered. The running cost is kept near zero on purpose, so the products do not need to grow in order to stay alive. A protection that switches off on a failed card is not a protection, so the safety net keeps running even if a payment lapses. We grow at the speed a subscription pays for, which is slow.
How the work is checked
We cannot show you users yet. We can show you the standard.
Every one of these is a gate that runs, not a policy that is written down.
One gate for every commit
A single command runs the type checker, the linter, the full test suite with coverage, a documented-counts check, a coverage census, the database and storage security-rules suites against a live emulator, and the web tier's own checks. Nothing merges around it.
A security rule without a test fails the build
Not a guideline — a gate, covering every rules path and every collection reached by a lookup inside a rule. It is written with its own limit stated: it proves coverage, never correctness.
A build step whose only job is catching us being confidently wrong
It fails the build whenever a number written in a document drifts from the number a real run produced. It exists because a confident stale figure is the most expensive recurring fault we have, and we would rather stop the build than let one reach you.
We keep a log of what we rejected
Not only what we shipped. Numbered decisions with their dead ends, and a findings register in which nothing is ever removed — every item ends fixed, parked, rejected or superseded, with a reason and a note on what would make us look again.
The threat model is public
The failure modes, the specific attacks and what stops each, and the explicit non-goals — on the product's own site, alongside a security contact, a disclosure policy and a good-faith safe-harbour promise.
We wrote down what our own testing cannot prove
A short beta cannot evaluate a handover that needs months to reach a single delivery. So the handover is proved by walking it end to end on an instrumented clock, and the beta measures the experience instead. We would rather publish that arithmetic than let a launch imply something it did not test.
Threat model ↗ · How it's built ↗ · Security ↗ · security.txt
Where we are
What has actually happened, with dates
Nothing on this list is a plan. Every row is a thing that has already occurred.
- 2 Jul 2026 Work on KinNest begins.
- 13 Aug 2026 Trademark application filed for the KinNest device mark, classes 9 and 42.
- 12 Aug 2026 KinNest moves to its own domain, kinnest.in, with its threat model, security page and disclosure policy published.
- 14 Sep 2026 Built4U Apps Private Limited is incorporated under the Companies Act 2013.
- 7 Oct 2026 GST and Udyam (MSME) registrations are complete. Registered as a Micro enterprise for 2026?27.
- In progress KinNest beta testing with real users. Not complete, and not claimed here as complete.
The company
Who stands behind this
- Registered name
- Built4U Apps Private Limited
- CIN
- U62011TN2026PTC197816
- Incorporated
- 14 September 2026, under the Companies Act 2013
- Type
- Private company limited by shares
- Registered office
- Medavakkam, Chennai, Tamil Nadu 600100, India
- Products
- KinNest — early access. LendBook — in development.
- GSTIN
- 33AAPCB1448M1ZE
- Udyam (MSME)
- UDYAM-TN-02-0514901 · Micro enterprise
- Registered
- GST and Udyam: 7 October 2026
The company was incorporated on 14 September 2026. GST registration (Regular) and Udyam registration were completed on 7 October 2026. The Udyam certificate classifies the company as a Micro enterprise for 2026–27, with services as its major activity. The full registered office is on the public register at mca.gov.in against the CIN above.
Contact
Reaching us
For anything about a product, an account, or privacy.
Replies within two working days
For journalists, and for hospitals, institutions or investors who want to understand what we are building.
Replies within two working days
Found a vulnerability? There is a published disclosure policy and a good-faith safe-harbour promise.
We reply, and we tell you when it is fixed