---

name: fiftyone-code-style description: Writes Python code following FiftyOne's official conventions. Use when contributing to FiftyOne, developing plugins, or writing code that integrates with FiftyOne's codebase.

FiftyOne Code Style

Module Template

Copy"""
Module description.

| Copyright 2017-2026, Voxel51, Inc.
| `voxel51.com <https://voxel51.com/>`_
|
"""
import logging
import os

import numpy as np

import eta.core.utils as etau

import fiftyone as fo
import fiftyone.core.fields as fof
import fiftyone.core.labels as fol
import fiftyone.core.utils as fou

logger = logging.getLogger(__name__)


def public_function(arg):
    """Public API function."""
    return _helper(arg)


def _helper(arg):
    """Private helper."""
    return arg

Import Organization

Four groups, alphabetized within each, separated by blank lines:

FiftyOne Import Aliases

Docstrings (Google-Style)

Copydef get_operator(operator_uri, enabled=True):
    """Gets the operator with the given URI.

    Args:
        operator_uri: the operator URI
        enabled (True): whether to include only enabled operators (True) or
            only disabled operators (False) or all operators ("all")

    Returns:
        an :class:`fiftyone.operators.Operator`

    Raises:
        ValueError: if the operator is not found
    """

Key patterns:

• Args with defaults: param (default): description
• Multi-line descriptions: indent continuation
• Cross-references: :class:fiftyone.module.Class``

Lazy Imports

Use fou.lazy_import() for optional/heavy dependencies:

Copyo3d = fou.lazy_import("open3d", callback=lambda: fou.ensure_package("open3d"))

mask_utils = fou.lazy_import(
    "pycocotools.mask", callback=lambda: fou.ensure_import("pycocotools")
)

Guard Patterns

Use hasattr() for optional attributes:

Copyif hasattr(label, "confidence"):
    if label.confidence is None or label.confidence < threshold:
        label = label.__class__()

Error Handling

Use logger.warning() for non-fatal errors:

Copytry:
    result = process_data(data)
except Exception as e:
    logger.warning("Failed to process data: %s", e)

Avoid Redundant Code

Before writing new functions, search for existing implementations:

• Local: search the FiftyOne source if available in the environment
• Remote: search https://github.com/voxel51/fiftyone
• Check fiftyone/core/utils.py and fiftyone/utils/* first

Common Utilities

Quick Reference