Templates capture setup once so every machine can start from a ready environment. 
from nullspace import Machine, Template, default_build_logger

builder = (
    Template()
    .from_python_image("3.12")
    .apt_install(["git", "curl"])
    .pip_install(["fastapi", "uvicorn"])
    .copy("./app.py", "/workspace/app.py")
    .set_workdir("/workspace")
)

build = Template.build(
    builder,
    name="fastapi-agent",
    tags=["stable"],
    on_log_entry=default_build_logger(),
)

with Machine.create(template=build.canonical_ref) as machine:
    result = machine.commands.run("python3 --version", shell=True)
    print(result.stdout)
Use Template.build_in_background() when a build should continue while your client disconnects or polls progress later. 
build = Template.build_in_background(builder, name="fastapi-agent", tags=["next"])
finished = build.wait_until_terminal()
print(finished.build.status)
The TypeScript SDK builds synchronously over the SSE stream; for background builds and polling, use the Python SDK, CLI, or HTTP API.
See the API reference for the full template build request schema and background-build polling.