Simplified Transfer Example

This repository contains a simplified example of a transfer application built with Rust, exposed via a JSON api.

The project demonstrates basic transfer functionality with multiple components organized in a workspace structure.

Components

• Transfer App (simple_transfer/transfer_app/)

  The main application that orchestrates transfers and provides the user interface.

• Transfer Library (simple_transfer/transfer_library/)

  Contains the core transfer logic and algorithms.

• Transfer NIF (simple_transfer/transfer_nif/)

  Provides native function bindings for performance-critical operations.

• Transfer Witness (simple_transfer/transfer_witness/)

  Handles cryptographic proof generation and verification for transfers.

Building

To build the entire workspace:

cargo build

If you want to use local proving, enable the gpu feature flag:

cargo build --features gpu

Note: CUDA can be tricky, and heavily depends on how your system is configured. You will at least need to know the path to the cuda library (e.g., /usr/local/cuda/lib64) and the path to your cuda binaries (e.g., /usr/local/cuda-13. 0/bin). The cuda library path contains files such as libculibos.a. The cuda binaries path contains files such as cuda-gdb-minimal. Based on these paths, set the following env vars before compiling.

export LD_LIBRARY_PATH=/usr/local/cuda-13.0/lib64:${LD_LIBRARY_PATH}
export PATH=/usr/local/cuda/bin:$PATH

Running

To run the application, some parameters need to be passed via the environment.

Variable	Meaning	Example
PRIVATE_KEY	The hex encoded private key for the account	0x00
USER_ADDRESS	The hex encoded address belonging to the private key	0x00
API_KEY	API key for Sepolia	supersecret
ETHERSCAN	API key for ether scan	supersecret
PROTOCOL_ADAPTER_ADDRESS_SEPOLIA	The hex encoded address of the forwarder contract	0x00
BONSAI_API_URL	URL for Bonsai proving	https://api.bonsai.xyz/
BONSAI_API_KEY	API key for Bonsai	supersecret
RPC_URL	URL for blockchain communication	https://eth-sepolia.g.alchemy.com/v2
TOKEN_ADDRESS	The hex encoded address for the token contract (e.g., USDC)	0x00
PERMIT2_ADDRESS	The hex encoded address for permit2 contract	0x00
DEFAULT_AMOUNT	The default amount for example transactions	10
DEADLINE	TODO	1893456000
FORWARDER_ADDRESS	The hex encoded address of the forwarder contract	0x00

To run the application, simply execute cargo run. If you want to use local proving, ensure the bonsai environment variables are unset (e.g., unset BONSAI_API_KEY; unset BONSAI_API_URL), and run cargo run --features gpu.

Docker

There is a Docker image in the repo to build your own image. Note that the docker image uses local proving and requires you to install nvidia cuda container tools.

docker build -t transfer .

Run the container as follows. Replace the values as necessary.

docker run -it --rm -p 8000:8000 --runtime=nvidia --gpus all transfer

Generate example JSON

The application has a flag to generate an example JSON request to mint.

cargo run -- --minting-example

if you have the application running a webserver somewhere, you can pipe the output through to a curl request.

cargo run -- --minting-example | curl -X POST -H "Content-Type: application/json" -d @- http://localhost:8000/api/mint