Hometr

Case studies / Web app · Telegram Mini App

What goes under the plaster stays on record.

Hometr («Хоуметр» in Russian) is a new platform for apartment renovation in Russia. The client needed one thing done right: wiring and pipes photographed with their position on the wall before they vanish under the plaster. Those photos build the apartment’s digital passport, which stays with the owner. We built the website, the API and a Telegram Mini App that keeps working on a site with no signal — between 2 and 16 September 2026.

hometr.ru ↗

hometr.ru
The first screen of hometr.ru, the renovation platform that records hidden works in the apartment's digital passport

The problem

Once the plaster is on, nobody knows where the cables run.

In a renovation, the work that matters most is the work nobody sees afterwards: wiring and pipes disappear under plaster and tiles. From then on, their position lives in the crew’s memory — for as long as the crew remembers.

Three kinds of people need that information, each for a different reason: the owner, who will one day drill into a wall; the foreman or craftsman, who has to be able to show the job was done properly; and the buyer of a second-hand flat, who wants to know what’s behind the walls.

Our answer

A photo for every surface, before it’s closed up.

The client wanted a tool that turns that memory into a record. We built a platform where hidden works are photographed with their position on the wall, stage by stage. Those photos make up the apartment’s digital passport, which belongs to the owner — not to the contractor. The interface is in Russian; for now, renovation crews work only in Krasnodar and Goryachy Klyuch.

✓Photos of hidden works with their position, converted to millimetres
✓A stage can’t be closed until every surface with hidden works has its photo
✓Photos linked in a chain: swap a file and the chain breaks
✓The passport stays with the owner and is shared through a revocable link

On site · Telegram Mini App

Four corners on a photo, and the wall becomes a map in millimetres.

A renovation site runs on phones, so the day-to-day work goes through a Telegram Mini App (m.hometr.ru) that opens inside the chat — nothing to install. The worker photographs the open wall and marks its four corners on the photo; the system straightens the perspective — a calculation called a homography — and converts positions into millimetres. We didn’t trust it by eye: an automated test requires the error to stay within 2% of the wall’s size, even with ±0.5 px of noise on each tap.

01Wall map. Four corners marked on the photo, perspective straightened, positions in millimetres.
02No half-closed stages. A stage stays open until every surface with hidden works has its photo.
03Evidence you can’t quietly swap. Photos are linked in a hash chain: replace a file and the chain breaks.
04Works without signal. An offline upload queue: shoot where there’s no connection, and the photos go up when it’s back.
05Four tabs, plus a bot. The Mini App has four tabs; and in any chat you can type a price and an area to the bot and get a quick estimate.
m.hometr.ru
Hometr’s Telegram Mini App on a phone: the Tools tab, checking a flat before buying — city, floor area, rooms, state of the finish and the listing price

In the screenshot: the Tools tab, checking a flat before you buy it — the listing price plus the likely cost of renovation. At the bottom, all four tabs: My renovation, Tools, Log, People.

On the website · free tools

Upload an estimate, see the suspicious lines.

Not everyone arrives with a renovation already under way: sometimes there’s only a contractor’s estimate and a doubt. For that moment the site offers a free check. You upload the estimate — XLSX, CSV or a PDF with a text layer — and every line is matched against a catalogue of 97 work items in 6 groups. The matching is fuzzy, so it recognises the same job even when it’s worded differently; then a set of rules flags the suspicious lines.

hometr.ru
The free estimate check on hometr.ru: uploading the file or pasting the text, the list of what the check looks for, and a wall cross-section with layer thicknesses

What the check looks for: duplicate lines, inflated quantities, prices outside the benchmark, missing work and calculation errors. And an honest caveat on the page itself: an automatic check does not replace a specialist’s site visit.

Three free tools on the website:

01Estimate check. /proverka-smety: a 97-item catalogue, fuzzy matching and rules for suspicious lines.
02Cost calculator. /raschet: to get a sense of what the works will cost.
03Measuring tool. /obmer: the photo never leaves the device.

Accepted formats

XLSXCSVPDF with text layer

The passport · privacy by design

The passport belongs to the owner. The address never leaves.

The digital passport doesn’t sit in the contractor’s drawer: it belongs to the owner, who can share it through a public link — with someone about to buy the flat, for example. That link (/p/…) never shows the address, and it can be revoked. When paperwork is needed, there’s a PDF act of hidden works and a ZIP export of the whole property.

Photos of the inside of a home, tied to an address, are sensitive data. So privacy went into the design from the start, rather than being bolted on at the end.

AddressEncrypted in the database
EXIFPhoto metadata is stripped on the server
UploadsShort-lived signed links for sending files
LinkThe public passport link never shows the address and can be revoked

How it’s built

Three front doors, one engine.

To the people using it, Hometr is three things: the website, the Mini App inside Telegram and the bot that answers in chat. Behind them is one engine — a Python API all three rely on — so the rules, like the stage that won’t close without photos, live in one place. Everything runs in Docker containers, and the codebase holds over 2,000 automated tests. It’s the same set-up we’d propose for a custom web app of yours.

WebsiteNext.js: the public pages and the free tools
Mini AppReact with the Telegram SDK, plus the offline upload queue
APIPython (FastAPI): one service behind the website, the Mini App and the bot
DataPostgreSQL, Redis and S3-compatible object storage for files
SecurityHSTS and CSP frame-ancestors headers: always HTTPS, and control over who can frame the pages
TestsOver 2,000 automated tests in the codebase

The result

A new platform, built on evidence rather than promises.

2weeks

of development, from 2 to 16 September 2026: website, API and Mini App

97items

of work in 6 groups: the catalogue the free estimate check matches against

≤2%

error allowed by the automated wall-map test, with ±0.5 px of noise on each tap

BUILT BY STUDIO REMARKA FOR THE CLIENT — VERIFIABLE AT hometr.ru

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