Skip to main content
Artifacts are the data objects produced by pipeline steps. ZenML automatically tracks, versions, and stores all artifacts, making it easy to trace data lineage, reproduce results, and share outputs across pipeline runs.

​
Understanding Artifacts

Every output from a step becomes an artifact: 
from zenml import step, pipeline
from typing import Annotated

@step
def load_data() -> Annotated[dict, "dataset"]:
    """This returns an artifact named 'dataset'."""
    return {"values": [1, 2, 3, 4, 5]}

@step
def process_data(dataset: dict) -> Annotated[list, "processed"]:
    """This takes 'dataset' artifact and produces 'processed' artifact."""
    return [x * 2 for x in dataset["values"]]
ZenML automatically:
  • Serializes outputs and stores them
  • Versions each artifact
  • Tracks lineage (which step produced it)
  • Links artifacts to pipeline runs

​
Naming Artifacts

1
Step 1: Use Annotated for Automatic Naming
2
The second argument in Annotated becomes the artifact name:
3
from typing import Annotated

@step
def train_model() -> Annotated[object, "trained_model"]:
    """Produces an artifact named 'trained_model'."""
    model = {"weights": [1, 2, 3]}
    return model
4
Step 2: Configure Custom Names
5
Use ArtifactConfig for more control:
6
from zenml import step, ArtifactConfig
from typing import Annotated

@step
def train_model() -> Annotated[
    object,
    ArtifactConfig(
        name="production_model",
        version=42,
        tags=["production", "v2"]
    )
]:
    """Produces a configured artifact."""
    model = {"weights": [1, 2, 3]}
    return model
7
Step 3: Dynamic Naming with Placeholders
8
Create dynamic artifact names:
9
from zenml import step, ArtifactConfig
from typing import Annotated

@step
def train_model() -> Annotated[
    object,
    ArtifactConfig(
        name="model_{date}_{time}",
    )
]:
    """Creates artifacts like 'model_20260309_143022'."""
    model = {"weights": [1, 2, 3]}
    return model
10
With custom placeholders:
11
@step(
    substitutions={"model_version": "v2.1"}
)
def train_model() -> Annotated[
    object,
    ArtifactConfig(
        name="model_{model_version}_{date}",
    )
]:
    """Creates artifacts like 'model_v2.1_20260309'."""
    model = {"weights": [1, 2, 3]}
    return model

​
Artifact Configuration

​
Adding Tags

Tag artifacts for easy discovery: 
from zenml import step, ArtifactConfig
from typing import Annotated

@step
def train_model() -> Annotated[
    object,
    ArtifactConfig(
        name="model",
        tags=["experiment", "baseline", "rf-classifier"]
    )
]:
    """Model artifact with searchable tags."""
    return train_random_forest()

​
Setting Artifact Type

Specify the semantic type of an artifact: 
from zenml import step, ArtifactConfig
from zenml.enums import ArtifactType
from typing import Annotated

@step
def train_model() -> Annotated[
    object,
    ArtifactConfig(
        name="model",
        artifact_type=ArtifactType.MODEL  # Semantic type
    )
]:
    """Explicitly mark this as a MODEL artifact."""
    return model

@step
def generate_report() -> Annotated[
    str,
    ArtifactConfig(
        name="report",
        artifact_type=ArtifactType.DATA  # Mark as DATA
    )
]:
    """Generate a data report."""
    return "Model evaluation report: ..."

​
Adding Metadata

Attach metadata to artifacts: 
from zenml import step, ArtifactConfig
from typing import Annotated

@step
def train_model(
    learning_rate: float,
    epochs: int
) -> Annotated[
    object,
    ArtifactConfig(
        name="model",
        run_metadata={
            "learning_rate": learning_rate,
            "epochs": epochs,
            "framework": "scikit-learn",
            "accuracy": 0.95
        }
    )
]:
    """Model with attached metadata."""
    model = train(learning_rate=learning_rate, epochs=epochs)
    return model

​
Multiple Artifacts

Return multiple artifacts from a single step: 
from typing import Tuple, Annotated
from zenml import step, ArtifactConfig

@step
def split_and_train() -> Tuple[
    Annotated[dict, ArtifactConfig(name="train_data", tags=["training"])],
    Annotated[dict, ArtifactConfig(name="test_data", tags=["testing"])],
    Annotated[object, ArtifactConfig(name="model", tags=["trained"])],
]:
    """Produce three separate artifacts."""
    # Split data
    train_data = {"X": [...], "y": [...]}
    test_data = {"X": [...], "y": [...]}
    
    # Train model
    model = train_on_data(train_data)
    
    return train_data, test_data, model
Use in pipeline: 
@pipeline
def ml_pipeline():
    train_data, test_data, model = split_and_train()
    
    # Use individual artifacts
    metrics = evaluate(model, test_data)
    report = generate_report(metrics)

​
Loading Artifacts

​
From the Client

Load artifacts using the ZenML client: 
from zenml.client import Client

client = Client()

# Load latest version of an artifact by name
artifact = client.get_artifact_version(name="trained_model")
model = artifact.load()

# Load specific version
artifact = client.get_artifact_version(
    name="trained_model",
    version="42"
)
model = artifact.load()

# Load by ID
artifact = client.get_artifact_version(
    name_id_or_prefix="550e8400-e29b-41d4-a716-446655440000"
)
model = artifact.load()

​
From Step Context

Access artifacts from previous runs: 
from zenml import step, get_step_context
from zenml.client import Client

@step
def compare_models(current_model: object) -> dict:
    """Compare current model with production model."""
    client = Client()
    
    # Load production model artifact
    production_artifact = client.get_artifact_version(
        name="production_model"
    )
    production_model = production_artifact.load()
    
    # Compare models
    current_accuracy = evaluate(current_model)
    production_accuracy = evaluate(production_model)
    
    return {
        "current": current_accuracy,
        "production": production_accuracy,
        "improvement": current_accuracy - production_accuracy
    }

​
From Previous Pipeline Runs

Load artifacts from specific pipeline runs: 
from zenml.client import Client

client = Client()

# Get a specific pipeline run
run = client.get_pipeline_run("my_pipeline_run_name")

# Load artifact from a specific step
model = run.steps["train_model"].outputs["trained_model"].load()

# Or get the output directly if there's only one
model = run.steps["train_model"].output.load()

​
Artifact Versioning

ZenML automatically versions artifacts: 
from zenml.client import Client

client = Client()

# List all versions of an artifact
artifact_versions = client.list_artifact_versions(
    name="trained_model"
)

for version in artifact_versions:
    print(f"Version {version.version}: {version.id}")
    print(f"  Created: {version.created}")
    print(f"  Tags: {version.tags}")

​
Version Promotion Workflow

@step
def promote_model_to_production(metrics: dict) -> None:
    """Promote model if it meets criteria."""
    client = Client()
    
    if metrics["accuracy"] > 0.95:
        # Get the current model from this run
        context = get_step_context()
        current_run = context.pipeline_run
        model_artifact = current_run.steps["train_model"].output
        
        # Update tags to mark as production
        client.update_artifact_version(
            artifact_version_id=model_artifact.id,
            tags=["production", "promoted"]
        )
        
        print(f"Model {model_artifact.id} promoted to production")
    else:
        print("Model did not meet promotion criteria")

​
Searching Artifacts

Find artifacts using filters: 
from zenml.client import Client
from zenml.models import ArtifactVersionFilter

client = Client()

# Find artifacts by name pattern
artifacts = client.list_artifact_versions(
    name="model"
)

# Filter by tags
artifacts = client.list_artifact_versions(
    tag="production"
)

# Complex filters
filter = ArtifactVersionFilter(
    name="trained_model",
    tag="production",
)
artifacts = client.list_artifact_versions(filter=filter)

for artifact in artifacts:
    print(f"{artifact.name} v{artifact.version}: {artifact.id}")

​
Artifact Lineage

Track where artifacts come from and where they’re used: 
from zenml.client import Client

client = Client()

# Get an artifact
artifact = client.get_artifact_version(name="trained_model")

# Find which step produced it
producer_step = artifact.producer_step_run
print(f"Produced by: {producer_step.name}")
print(f"In pipeline: {producer_step.pipeline_run.name}")

# Find which steps consumed it (if any)
# Navigate through pipeline runs to find consumers

​
Artifact Visualization

Some artifacts can be visualized in the ZenML dashboard: 
import pandas as pd
import matplotlib.pyplot as plt
from zenml import step
from typing import Annotated

@step
def analyze_data() -> Annotated[pd.DataFrame, "analysis"]:
    """DataFrame artifacts are automatically visualized."""
    df = pd.DataFrame({
        "metric": ["accuracy", "precision", "recall"],
        "value": [0.95, 0.93, 0.96]
    })
    return df

@step
def create_plot() -> Annotated[plt.Figure, "performance_plot"]:
    """Matplotlib figures are visualized in the dashboard."""
    fig, ax = plt.subplots()
    ax.plot([1, 2, 3, 4], [1, 4, 2, 3])
    ax.set_title("Model Performance")
    return fig

​
Best Practices

Use Descriptive Names

Give artifacts clear, meaningful names that describe their contents

Tag Consistently

Use a consistent tagging strategy across your team

Add Rich Metadata

Attach relevant metadata to help track experiments and results

Version Strategically

Use explicit versioning for important artifacts

Clean Up Old Artifacts

Periodically remove unused artifacts to save storage

Document Artifact Structure

Document the schema/structure of complex artifacts

​
Artifact Storage

Artifacts are stored in the artifact store configured in your stack: 
# View current artifact store
zenml stack describe

# List available artifact stores
zenml artifact-store list

# Register a new artifact store (e.g., S3)
zenml artifact-store register my_s3_store \
  --flavor=s3 \
  --path=s3://my-bucket/zenml-artifacts

​
Troubleshooting

​
Artifact Not Found

If you can’t find an artifact: 
from zenml.client import Client

client = Client()

# List all artifacts to find the right name
all_artifacts = client.list_artifact_versions()
for artifact in all_artifacts:
    print(f"{artifact.name} v{artifact.version}")

​
Loading Fails

If artifact loading fails, check:
  1. Artifact store is accessible
  2. Required dependencies are installed
  3. Artifact hasn’t been deleted
try:
    artifact = client.get_artifact_version(name="model")
    model = artifact.load()
except Exception as e:
    print(f"Failed to load artifact: {e}")
    print(f"Artifact store: {client.active_stack.artifact_store.name}")

​
Next Steps

Writing Steps

Learn how to create steps that produce artifacts

Step Context

Access artifacts within step execution

Stack Configuration

Configure artifact stores for your pipelines

Build docs developers (and LLMs) love

Get started for freeTalk to us