WorldId is one of the core pillars of the Worldcoin Protocol, providing a privacy preserving identity primitive which enables a robust mechanism for proof of personhood. The protocol works by maintaining an onchain representation of a Semaphore set, with each identity in the set representing a verified human. With WorldId, users can create Zero Knowledge proofs proving that they are a unique member of the set. In order to create a ZKP, users need to generate a merkle proof for their identity in the set.

The world-tree is a service that syncs the state of the onchain merkle tree and delivers inclusion proofs for any given identity.

To install the world-tree, make sure you have Rust installed and run the following commands.

git clone https://github.com/worldcoin/world-tree.git &&
cargo install --path .

To run the world-tree, you can run the following command.

world-tree --config <path_to_config.toml>

To see an example configuration file, see bin/world_tree.toml. You can also specify the necessary configuration variables via environment variables.

To run this service for local testing, you can execute the following command.

docker compose up -d --build

This command will build the docker image locally and start the service itself along with an anvil instance to serve as a test blockchain.

Anvil will fork Ethereum mainnet and use the production WorldIdIdentityManager contract, but with only a few identities inserted.

To test that inclusion proofs work you can execute the following curl command:

curl -X POST http://localhost:8080/inclusionProof -H "Content-Type: application/json" -d '{ "identityCommitment": "0x3017972D13A39795AD0D1C3A670D3D36A399B4435E61A510C2D57713D4F5C3DE" }'