Templates

A template is the environment a sandbox starts from: a Debian image with runtimes and tools installed, captured as a snapshot so sandboxes are restored rather than booted. It also sets the sandbox's CPU and memory.

Built-in templates#

Every template is based on Debian 12 and includes git, curl and CA certificates. Pass the name to client.sandbox(template=…).

claude-code#

Everything Claude Code needs, plus the common toolchains it reaches for.

• Claude Code CLI (@anthropic-ai/claude-code)
• Node.js 22, Rust (stable), Python 3 with pip, venv and uv
• build-essential, jq, ripgrep, fd-find, openssh-client

with client.sandbox(template="claude-code") as sb:
    print(sb.exec(["claude", "--version"]).stdout)

python#

A small Python environment. Use uv to manage projects and dependencies.

with client.sandbox(template="python") as sb:
    sb.exec(["sh", "-c", "uv init demo && cd demo && uv add pandas"])
    print(sb.exec(["sh", "-c", "cd demo && uv run python -c 'import pandas; print(pandas.__version__)'"]).stdout)

nodejs#

Node.js 22 and npm.

with client.sandbox(template="nodejs") as sb:
    sb.exec(["sh", "-c", "npm init -y && npm install express"])

ci-runner#

For building and testing code: Node.js 22, Rust, uv, build-essential, pkg-config, libssl-dev, libclang-dev and jq.

minimal#

One vCPU with git, curl and jq. The lightest environment, for quick commands.

Custom templates#

Build your own template from a Dockerfile, then use it by name like a built-in one.

client.create_template("data-science", dockerfile="""
FROM debian:bookworm-slim
RUN apt-get update && apt-get install -y --no-install-recommends python3 python3-venv git curl ca-certificates
RUN python3 -m venv /opt/venv && /opt/venv/bin/pip install pandas numpy scikit-learn
ENV PATH="/opt/venv/bin:$PATH"
""")

with client.sandbox(template="data-science") as sb:
    print(sb.exec(["python", "-c", "import sklearn; print(sklearn.__version__)"]).stdout)

Manage your templates with client.list_templates(), client.get_template(name) and client.delete_template(name).

How templates are stored#

A template is built once and captured as a snapshot. Sandboxes started from it share its disk blocks, which are stored by content, and each sandbox writes to its own private layer on top:

Identical blocks across templates are stored once, so a custom template only adds what is different about it.