C-Twin is a 3D digital twin of Istanbul that runs in the browser. You can fly over it, scrub the clock back to 2020, and — with a Talivio account — walk its streets, drive its roads and ride its trains. It is early, it is free, and it is the first Talivio product you can move through rather than click through.

Why a Digital Twin, and Why Istanbul

Most of what we build is business software: invoicing, VAT returns, compliance reporting. All of it works on a model of something real, and a city is the largest "something real" we could think of. Istanbul has streets, buildings, motorways, metro lines, buses, ferries and weather, and nearly all of it is published as open data. Our job in C-Twin is to rebuild that faithfully enough that moving through it feels like something, and then let the useful parts grow on top: live city data you can stand inside, routes you can drive before you drive them, and eventually storefronts for the businesses that actually occupy those buildings.

We did not start with a plan for the whole city. We started with a world that already exists and a rule that everything in it must be traceable to a source we can name.

Why Kayabaşı and Tuzla

The two pilot districts were not chosen by population or by prestige. They are where the developers building C-Twin live. Kayabaşı in Başakşehir and Tuzla are the neighbourhoods our team walks and drives through every day, which means every misplaced building, every road that ends too early and every bus that turns the wrong way gets noticed by someone who knows the street. A digital twin is only as good as the corrections it gets, and the fastest corrections come from people who live inside it.

The two districts sit on opposite sides of the Bosphorus, so joining them meant modelling the entire TEM motorway corridor, all the way across the Fatih Sultan Mehmet Bridge, as a single continuous scene. That corridor is now the backbone of the twin. Beyond the modelled areas the rest of the province is a relief map with distant city silhouettes, so the horizon looks like Istanbul instead of an empty void.

Next: Istanbul to Tallinn

Talivio is registered in Tallinn, and the team is split between the two cities. The next link we are building runs between our office in Tallinn and Istanbul, for the same reason the first two districts were chosen: it is where we are. Tallinn brings its own open-data ecosystem, a very different climate and a much smaller, denser city, which is exactly the kind of contrast that tells us whether the engine generalises or whether it only knows Istanbul. We will write about it when it works, not before.

What You Can Do Today

Without an account, anyone can:

  • fly the camera anywhere in the modelled area,
  • move a time slider back to 1 January 2020 and see the city at that moment,
  • take a cinematic tour and use photo mode,
  • open the data panel with live weather, traffic alerts and city cameras.

Signing in with a Talivio account unlocks the playable parts: walking, driving cars, a motorcycle, a bicycle or an articulated truck (with fuel, damage, a driving licence and traffic fines), riding the rail network and getting off at stations, and taking taxi and courier jobs. Jobs pay in tali, an in-game currency. Tali is earned by playing only. It cannot be bought, sold or withdrawn.

A City That Moves on Its Own

A digital twin is only interesting if the city is doing something while you watch. C-Twin pulls in live and scheduled data and turns it into things you can see:

  • Weather. Live conditions drive rain, fog and the light. The sun and moon sit where they really are for the chosen time.
  • Rail. 26 rail lines and 321 stations, with trains running on their published timetables. We do not have live train positions, so we don't pretend to.
  • Buses. IETT buses run on the timetable and are corrected with live positions where those are available.
  • The city around you. Traffic levels, IBB alerts and live city cameras appear in the data panel, alongside recent earthquakes from AFAD.

Built on Open Data, Credited in the App

Everything in the world comes from sources we can name. Buildings and roads come from OpenStreetMap (ODbL) and Overture Maps, with Microsoft building footprints filling gaps. Terrain comes from the open GEDTM30 elevation model (CC BY 4.0) and Copernicus GLO-30. Transit comes from IBB's open data portal and IETT's GTFS feed. People are built from MakeHuman (CC0), and many props from CC0 model kits. Every region has its own "Sources & licenses" page in the app, and when an asset's licence turned out to be different from what we assumed, we took it out.

We are equally strict about what we claim. Open map data rarely records how tall a building is, so in many places floor counts and heights are still estimates rather than measurements. They improve district by district as we check them, and we would rather say that plainly than call the model exact.

How It Is Built

The client is React 19 and three.js, written in TypeScript and bundled with Vite. The backend is Laravel 13, which proxies and caches the live data feeds (no source is hit on every page view), keeps the history that powers the time slider, and handles accounts through Talivio sign-in. The 3D engine started from two MIT-licensed open-source projects, Procedural Tokyo and Portwise, which we forked and have since rebuilt heavily. Both are credited in the repository.

The pace has been unusual even by our standards. The first commit landed on 5 October 2026. Nine days later the project has gone from a single neighbourhood to a 33-section motorway corridor joining two districts across the Bosphorus. Most of that work was done by AI agents. People set the direction, made the decisions and approved every change.

What Is Not Switched On Yet

Some things are built but deliberately turned off:

  • Exploring together. The real-time multiplayer layer for seeing and moving with other players exists. It stays off until our privacy texts have been reviewed by a lawyer.
  • Open sign-up with email and password. For now you sign in with a Talivio account.
  • Business storefronts and user-uploaded building models. Both are built and both are behind flags.

Other things are only planned: boarding buses, freight jobs for trucks, building interiors, a much larger part of Istanbul, and the Tallinn link above. We will write about them when they work, not before.

Try It

Open c-twin.talivio.com in a desktop browser. A recent laptop with a dedicated or modern integrated GPU gives the best experience. Fly around first, then sign in with your Talivio account and take a car down the TEM. If something looks wrong, a building in the wrong place or a road that ends too early, tell us. A twin is only as good as the corrections it gets, and right now the people correcting it live in two districts. We would like that number to grow.