Canonical bridge

Snowbridge

Snowbridge is the official bridge between Polkadot and Ethereum. It is built into the Polkadot SDK, owned by the Polkadot community, has no token and uses no multisig.

Official website

How it works

1You start the transfer in the Snowbridge app or in a Polkadot wallet that supports it.
2Each side runs a light client of the other network: Polkadot checks Ethereum block proofs, and an Ethereum contract checks Polkadot finality proofs.
3Once the proof is accepted, the tokens are released on the destination network: Ethereum tokens arrive on Polkadot Hub, and DOT can be moved to Ethereum.

Trust model

No group of signers holds the funds. Transfers are accepted only with a cryptographic proof checked on-chain, so you rely on the security of Polkadot and Ethereum themselves and on the correctness of the bridge code.

Strengths

The official system bridge of Polkadot, governed by the Polkadot community.
No multisig and no bridge token.
Works with Polkadot Hub and many parachains.

Limitations

Slower than liquidity bridges: a transfer can take from tens of minutes to over an hour.
Connects only Polkadot and Ethereum.
Ethereum gas fees apply on the Ethereum side.