ThreeFold Chain
ThreeFold blockchain (aka TFChain) serves as a registry for Nodes, Farms, Digital Twins and Smart Contracts.
It is the backbone of [ZOS](https://github.com/threefoldtech/zos) and other components.
## Deployed instances
- Development network (Devnet):
- Polkadot UI: [https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.dev.grid.tf#/explorer](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.dev.grid.tf#/explorer)
- Websocket url: `wss://tfchain.dev.grid.tf`
- GraphQL UI: [https://graphql.dev.grid.tf/graphql](https://graphql.dev.grid.tf/graphql)
- QA testing network (QAnet):
- Polkadot UI: [https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.qa.grid.tf#/explorer](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.qa.grid.tf#/explorer)
- Websocket url: `wss://tfchain.qa.grid.tf`
- GraphQL UI: [https://graphql.qa.grid.tf/graphql](https://graphql.qa.grid.tf/graphql)
- Test network (Testnet):
- Polkadot UI: [https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.test.grid.tf#/explorer](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.test.grid.tf#/explorer)
- Websocket url: `wss://tfchain.test.grid.tf`
- GraphQL UI: [https://graphql.test.grid.tf/graphql](https://graphql.test.grid.tf/graphql)
- Production network (Mainnet):
- Polkadot UI: [https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.grid.tf#/explorer](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2F/tfchain.grid.tf#/explorer)
- Websocket url: `wss://tfchain.grid.tf`
- GraphQL UI: [https://graphql.grid.tf/graphql](https://graphql.grid.tf/graphql)
## Create a TFChain twin
A twin is a unique identifier linked to a specific account on a given TFChain network.
Actually there are 2 ways to create a twin:
- via Dashboard portal: see related [documentation](../getstarted/TF_Dashboard/TF_Dashboard.html#create-polkadot-extension-account).
- via TFConnect app: a twin is automatically generated while creating a farm (in this case the twin will be created on mainnet)
## Get your twin ID
One can retrieve the twin ID associated to his account going to `Developer` -> `Chain state` -> `tfgridModule` -> `twinIdByAccountID()`.
