leo devnode
A devnode is a lightweight-node network that bypasses the consensus algorithm and the requirement to generate proofs for deployment and execution transactions. It is a development tool intended for rapidly iterating on Aleo program design and running end-to-end tests prior to deploying Aleo programs to Testnet and Mainnet.
leo devnode is the recommended local development tool for lightweight testing. The older leo devnet command (which requires a full snarkOS installation and spins up a multi-validator network) remains available for more complex testing scenarios.
To initialize a devnode, run the following command:
leo devnode start --private-key <PRIVATE_KEY>
The default endpoint for a local devnode is http://localhost:3030.
Press Ctrl+C to stop the devnode. If started with --storage, the ledger state is saved and can be resumed by running the same command again. If started without --storage, the ledger is discarded when the devnode exits.
leo devnode start
leo devnode start [OPTIONS]
| Flag | Short | Default | Description |
|---|---|---|---|
--private-key | Private key (required, or set via PRIVATE_KEY environment variable) | ||
--verbosity | -v | 2 | Log verbosity level (0–2) |
--socket-addr | -a | 127.0.0.1:3030 | Address and port for the REST API |
--genesis-path | -g | (built-in) | Path to a custom genesis block file |
--manual-block-creation | -m | false | Disable automatic block creation after broadcast |
--storage | -s | (in-memory) | Directory for persistent ledger storage. If -s is given without a path, defaults to ./devnode/ |
--clear-storage | -c | false | Clear the ledger directory before starting. Requires --storage |
Examples
# In-memory (ephemeral, no persistence)
leo devnode start --private-key APrivateKey1zkp8CZNn3yeCseEtxuVPbDCwSyhGW6yZKUYKfgXmcpoGPWH
# Persistent, default directory (./devnode/)
leo devnode start -s
# Persistent, custom directory
leo devnode start -s ./my-ledger
# Fresh start — wipe existing ledger before starting
leo devnode start -s -c
leo devnode start -s ./my-ledger -c
# Manual block creation (blocks only advance when explicitly requested)
leo devnode start --private-key APrivateKey1zkp8CZNn3yeCseEtxuVPbDCwSyhGW6yZKUYKfgXmcpoGPWH -m
leo devnode advance
Manually advances the ledger by creating new blocks. Useful when running with --manual-block-creation.
leo devnode advance [NUM_BLOCKS] [OPTIONS]
| Argument / Flag | Default | Description |
|---|---|---|
NUM_BLOCKS | 1 | Number of blocks to create |
--socket-addr | 127.0.0.1:3030 | Address of the running devnode |
Examples
# Advance by 1 block
leo devnode advance
# Advance by 10 blocks
leo devnode advance 10
# Advance a devnode running on a non-default address
leo devnode advance 5 --socket-addr 127.0.0.1:4040
Skipping Proof Generation
When targeting a devnode, two proof-generation steps can be skipped for faster iteration. Proofs are not verified by the devnode, so generating them is unnecessary overhead.
Deploying a Program
leo deploy --skip-deploy-certificate --endpoint http://localhost:3030
--skip-deploy-certificate skips generating the deployment proof. Without it, deployment will still work but will be significantly slower.
Executing a Transition
leo execute <TRANSITION> <INPUTS> --skip-execute-proof --endpoint http://localhost:3030
--skip-execute-proof skips generating the execution proof. Without it, execution will still work but will be significantly slower.
Upgrading a Program
leo upgrade --skip-deploy-certificate --endpoint http://localhost:3030
Evaluating View Functions
A devnode exposes two REST endpoints for evaluating a program's view fn against the current ledger state. View functions are read-only: they compute a result from on-chain state without producing a transaction, so no key, signature, or proof is required.
Both endpoints are mounted under the network prefix (e.g. testnet) and are also available behind the v1 and v2 API version prefixes:
| Method | Path | Description |
|---|---|---|
POST | /{network}/program/{id}/view/{function} | Evaluate a view function at the latest block height. |
POST | /{network}/program/{id}/view/{function}/{height} | Evaluate a view function at a specific block height. |
The request body is a JSON array of the view function's inputs, each encoded as an Aleo value string. Pass [] when the function takes no inputs. The response is a JSON array of the function's outputs.
The latest-height endpoint accepts an optional ?metadata=true query parameter; when set, the response is wrapped as { "data": [...], "height": <block_height> } instead of a bare output array.
Examples
# Evaluate `my_view` on `my_program.aleo` at the latest height
curl -X POST http://localhost:3030/testnet/program/my_program.aleo/view/my_view \
-H 'Content-Type: application/json' \
-d '["1u32", "2u32"]'
# Include the block height the result was evaluated at
curl -X POST 'http://localhost:3030/testnet/program/my_program.aleo/view/my_view?metadata=true' \
-H 'Content-Type: application/json' \
-d '[]'
# Evaluate against historical state at block height 10
curl -X POST http://localhost:3030/testnet/program/my_program.aleo/view/my_view/10 \
-H 'Content-Type: application/json' \
-d '[]'
Under the v2 prefix the endpoints return 422 Unprocessable Entity for malformed inputs and 400 Bad Request for an unknown view function or a height before the program was deployed.
Typical Workflow
# 1. Start a persistent devnode
leo devnode start --private-key APrivateKey1zkp8CZNn3yeCseEtxuVPbDCwSyhGW6yZKUYKfgXmcpoGPWH -s
# 2. Deploy your program (in another terminal, from your Leo project directory)
leo deploy --skip-deploy-certificate --endpoint http://localhost:3030
# 3. Execute a transition
leo execute <TRANSITION> <INPUTS> --skip-execute-proof --endpoint http://localhost:3030
# 4. Reset and start fresh when needed
leo devnode start --private-key APrivateKey1zkp8CZNn3yeCseEtxuVPbDCwSyhGW6yZKUYKfgXmcpoGPWH -s -c