leo build

To compile your program into Aleo instructions and verify that it builds properly, run:

leo build

The build command automatically creates a build/ directory. For a single project, this directory is in the project directory. For a workspace, it is at the workspace root and is shared by all members. Each program and dependency gets a build/{program}/ directory with its compiled .aleo bytecode and ABI.

console output:

  Leo 🔨 Compiling '{PROGRAM_NAME}.aleo'
  Leo     Program size: 0.20 KB / 2000.00 KB
  Leo ✅ Compiled '{PROGRAM_NAME}.aleo' into Aleo instructions.
  Leo     Import '{DEPENDENCY}.aleo': program size: 0.17 KB / 2000.00 KB
  Leo ✅ Generated ABI for program '{PROGRAM_NAME}.aleo'.

The output has one import line for each imported program. Leo does not show this line when the program has no imports.

The build also generates an ABI file at build/{PROGRAM_NAME}/abi.json describing your program's public interface (transitions, mappings, and types). See the ABI Generation guide for details on the format and type lowering specification.

Checksums

The std::prog::function_checksum function returns program, entry, and view function checksums. Use these checksums in a constructor that pins functions across upgrades. To print the checksums, pass --checksums:

leo build --checksums

console output:

  Leo     The program checksum is: '[141u8, 87u8, ...]'.
  Leo       `main` function checksum is: '[140u8, 56u8, ...]'.
  Leo       `peek` function checksum is: '[239u8, 16u8, ...]'.

Each checksum is the 32-byte SHA3-256 hash of the component's Aleo source. The --json-output build JSON also contains these checksums. They are integer arrays under program_checksum and function_checksums. Use leo build --json-output to consume them in a program.

Flags

--build-tests
    Build tests along with the main program and dependencies.
--checksums
    Print the program checksum and the checksum of each entry and view function
    (the `std::prog::function_checksum` targets).
--no-cache
    Don't use the dependency cache.
--no-local
    Don't use the local source code.
--network <NETWORK>
    The network to build for. Overrides the `NETWORK` environment variable.
--endpoint <ENDPOINT>
    The endpoint to resolve network dependencies from. Overrides the `ENDPOINT` environment variable.
--network-retries <N>
    Number of times to retry a network request on transient transport failure, with
    exponential backoff (1 s, 2 s, 4 s, … capped at 64 s). Overrides the
    NETWORK_RETRIES environment variable. Defaults to 2. HTTP errors and broadcast
    calls are not retried.

Workspace Behavior

When run inside a workspace:

• From workspace root: Builds all members in dependency order.
• From a member directory: Builds only that member.
• With --package <NAME>: Builds only the specified member.

# Build all workspace members
leo build

# Build only the swap member
leo build -p swap