Spans

The spans client’s list, delete, and annotate methods are currently in BETA. The API may change without notice, and a one-time warning is emitted on first use. All other spans methods (log, update_evaluations, update_annotations, update_metadata, export_to_df, export_to_parquet) are stable.

Log, query, and update LLM traces programmatically. Upload bulk traces or update evaluations and annotations after the fact.

Key Capabilities

List and filter spans for a project
Bulk upload traces from offline processing
Update evaluations asynchronously (LLM-as-judge patterns)
Annotate spans by ID or attach annotations to traces in bulk
Attach custom metadata for filtering and analysis
Export spans for offline analysis
Permanently delete spans by ID

List Spans

For downloading large volumes of spans, use export_to_df instead.

List spans for a project within an optional time window. Spans are returned in descending start-time order (most recent first). If start_time and end_time are not provided, the last seven days are queried.

from datetime import datetime

resp = client.spans.list(
    project="your-project-name-or-id",
    start_time=datetime(2024, 1, 1),  # optional
    end_time=datetime(2024, 2, 1),    # optional
    limit=100,
)

for span in resp.spans:
    print(span.span_id, span.name)

Filter Spans

Use the filter parameter to narrow results by status, evaluation labels, annotation labels, or latency:

# Filter by status
resp = client.spans.list(
    project="your-project-name-or-id",
    filter="status_code = 'ERROR'",
)

# Filter by evaluation label
resp = client.spans.list(
    project="your-project-name-or-id",
    filter="eval.Correctness.label = 'correct'",
)

# Filter by annotation label
resp = client.spans.list(
    project="your-project-name-or-id",
    filter="annotation.Quality.label = 'good'",
)

# Filter by latency
resp = client.spans.list(
    project="your-project-name-or-id",
    filter="latency_ms > 1000",
)

# Combine filters with AND / OR
resp = client.spans.list(
    project="your-project-name-or-id",
    filter="status_code = 'ERROR' AND eval.Correctness.label = 'correct'",
)

For details on pagination, field introspection, and data conversion (to dict/JSON/DataFrame), see Response Objects.

Log Spans

Upload traces in bulk from offline processing or batch evaluation.

import pandas as pd

# Prepare spans DataFrame
spans_df = pd.DataFrame([
    {
        "context.span_id": "span-1",
        "context.trace_id": "trace-1",
        "name": "llm_call",
        "span_kind": "LLM",
        "start_time": "2024-01-15T10:00:00Z",
        "end_time": "2024-01-15T10:00:02Z",
        "attributes.llm.model_name": "gpt-4",
        "attributes.llm.input_messages": [...],
        "attributes.llm.output_messages": [...],
    },
])

# Optional: include evaluations
evals_df = pd.DataFrame([
    {
        "context.span_id": "span-1",
        "eval.Correctness.label": "correct",
        "eval.Correctness.score": 1.0,
        "eval.Correctness.explanation": "The model's response was accurate.",
    },
])

# Log spans
response = client.spans.log(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=spans_df,
    evals_dataframe=evals_df,  # Optional
)

print(f"Logged spans successfully: {response.status_code}")

Log Spans Only

client.spans.log(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=spans_df,
)

Update Evaluations

Add or update evaluations for existing spans (useful for LLM-as-judge patterns).

import pandas as pd

evals_df = pd.DataFrame([
    {
        "context.span_id": "span-1",
        "eval.Relevance.label": "relevant",
        "eval.Relevance.score": 0.95,
        "eval.Relevance.explanation": "The response directly answers the question.",
    },
    {
        "context.span_id": "span-2",
        "eval.Relevance.label": "not_relevant",
        "eval.Relevance.score": 0.2,
        "eval.Relevance.explanation": "The model's response was not relevant.",
    },
])

response = client.spans.update_evaluations(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=evals_df,
)

print("Updated evaluations successfully")

Batch Evaluation Pattern

# Run async LLM evaluations on existing traces
async def evaluate_traces():
    # Fetch traces to evaluate
    traces = fetch_recent_traces()

    # Run LLM-as-judge evaluations
    eval_results = []
    for trace in traces:
        score = await llm_judge.evaluate(trace)
        eval_results.append({
            "context.span_id": trace.span_id,
            "name": "Quality",
            "score": score,
        })

    # Upload evaluations
    evals_df = pd.DataFrame(eval_results)
    client.spans.update_evaluations(
        space_id="your-space-id",
        project_name="my-llm-app",
        dataframe=evals_df,
    )

Annotate Spans

Write human annotations to a batch of spans by ID. Annotations are upserted by annotation config name for each span; submitting the same name for the same span overwrites the previous value. Up to 1000 spans may be annotated per request. Spans are looked up within the specified time window (defaulting to the last 31 days). If any span ID in the batch is not found within the window, the entire request is rejected with a 404 error.

from datetime import datetime
from arize.spans.types import AnnotateRecordInput
from arize.annotation_queues.types import AnnotationInput

client.spans.annotate(
    project="your-project-name-or-id",
    space="your-space-name-or-id",  # required when project is a name
    annotations=[
        AnnotateRecordInput(
            record_id="your-span-id",
            values=[
                AnnotationInput(name="accuracy", label="correct", score=1.0),
                AnnotationInput(name="notes", text="Verified by reviewer"),
            ],
        ),
    ],
    start_time=datetime(2026, 4, 1),  # optional, defaults to 31 days ago
    end_time=datetime(2026, 5, 1),    # optional, defaults to now
)

Update Annotations

Add human feedback and annotations to spans.

import pandas as pd

annotations_df = pd.DataFrame([
    {
        "context.span_id": "span-1",
        "annotation.Quality.label": "correct",
        "annotation.Quality.score": 1.0,
        "annotation.Quality.text": "Verified by human reviewer",
    },
])

response = client.spans.update_annotations(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=annotations_df,
)

print("Updated annotations successfully")

Update Metadata

Attach or patch custom metadata on existing spans for filtering and analysis. The method uses JSON Merge Patch semantics and supports three input approaches.

Method 1: Direct Field Columns

Set individual metadata fields using attributes.metadata.<field> column names. This is the simplest approach.

import pandas as pd

metadata_df = pd.DataFrame([
    {
        "context.span_id": "span-1",
        "attributes.metadata.customer_id": "cust-456",
        "attributes.metadata.experiment_version": "v2",
        "attributes.metadata.region": "us-west",
    },
    {
        "context.span_id": "span-2",
        "attributes.metadata.customer_id": "cust-789",
        "attributes.metadata.region": "eu-central",
    },
])

response = client.spans.update_metadata(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=metadata_df,
)

print(f"Updated: {response['spans_updated']}, Failed: {response['spans_failed']}")

Method 2: Patch Document Column

Provide a JSON patch document per span for more control. The patch is applied after any field columns. The default column name is "patch_document".

metadata_df = pd.DataFrame([
    {
        "context.span_id": "span-1",
        "patch_document": {"tag": "important", "priority": "high"},
    },
    {
        "context.span_id": "span-2",
        "patch_document": {"tag": "standard"},
    },
])

response = client.spans.update_metadata(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=metadata_df,
)

Use a custom column name with the patch_document_column_name parameter:

response = client.spans.update_metadata(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=metadata_df,
    patch_document_column_name="my_patch_col",
)

Method 3: Combined Approach

Use both field columns and a patch document. The patch document is applied last and overrides any conflicting field column values.

metadata_df = pd.DataFrame([
    {
        "context.span_id": "span-1",
        "attributes.metadata.tag": "important",
        "patch_document": {"priority": "high"},  # Applied after field columns
    },
])

response = client.spans.update_metadata(
    space_id="your-space-id",
    project_name="my-llm-app",
    dataframe=metadata_df,
)

Type Handling

Python type	Stored as
`str`	string
`int` / `float`	number
`bool`	string (`"True"` / `"False"`)
`None`	JSON `null` (field is set to null, not removed)
`dict` / `list`	JSON string

Setting a field to None stores JSON null — it does not remove the field. This differs from standard JSON Merge Patch behavior.

Response Structure

update_metadata returns a dictionary with the following keys:

Key	Description
`spans_processed`	Total spans in the input DataFrame
`spans_updated`	Spans successfully updated
`spans_failed`	Spans that failed to update
`errors`	List of `{"span_id": ..., "error_message": ...}` for each failure

response = client.spans.update_metadata(...)

print(f"Processed: {response['spans_processed']}")
print(f"Updated:   {response['spans_updated']}")
print(f"Failed:    {response['spans_failed']}")

for err in response.get("errors", []):
    print(f"  span {err['span_id']}: {err['error_message']}")

Delete Spans

Permanently delete spans by their IDs. This operation is irreversible. Only spans within the 2-year lookback window are considered; older spans are not affected. Span IDs not found within the lookback window are returned in not_deleted_span_ids. Returns a DeleteSpansResponse with:

completed — True if no retry is needed.
deleted_span_ids — IDs confirmed deleted.
not_deleted_span_ids — IDs not deleted (either not found in the lookback window, or not reached when completed is False).

When completed is False, retry the original full request to complete the deletion.

result = client.spans.delete(
    project="your-project-name-or-id",
    span_ids=["span-id-1", "span-id-2"],
    space="your-space-name-or-id",  # required when project is a name
)

if result.completed:
    print(f"Deleted {len(result.deleted_span_ids)} spans")
else:
    print("Deletion incomplete — retry the original request to finish")

Export Spans

Export spans for offline analysis, custom processing, or archival.

from datetime import datetime

start_time = datetime.strptime("2024-01-01", "%Y-%m-%d")
end_time = datetime.strptime("2026-01-01", "%Y-%m-%d")

# Export to DataFrame
df = client.spans.export_to_df(
    space_id="your-space-id",
    project_name="my-llm-app",
    start_time=start_time,
    end_time=end_time,
)

print(f"Exported {len(df)} spans")

Export to Parquet

client.spans.export_to_parquet(
    space_id="your-space-id",
    project_name="my-llm-app",
    start_time=start_time,
    end_time=end_time,
    path="./spans_export.parquet",
)

Export capabilities:

Time-range filtering
DataFrame or Parquet output
Efficient Arrow Flight transport for large exports
Progress bars for long-running exports

API reference

API clients

Key Capabilities

List Spans

Filter Spans

Log Spans

Log Spans Only

Update Evaluations

Batch Evaluation Pattern

Annotate Spans

Update Annotations

Update Metadata

Method 1: Direct Field Columns

Method 2: Patch Document Column

Method 3: Combined Approach

Type Handling

Response Structure

Delete Spans

Export Spans

Export to Parquet

​Key Capabilities

​List Spans

​Filter Spans

​Log Spans

​Log Spans Only

​Update Evaluations

​Batch Evaluation Pattern

​Annotate Spans

​Update Annotations

​Update Metadata

​Method 1: Direct Field Columns

​Method 2: Patch Document Column

​Method 3: Combined Approach

​Type Handling

​Response Structure

​Delete Spans

​Export Spans

​Export to Parquet

Key Capabilities

List Spans

Filter Spans

Log Spans

Log Spans Only

Update Evaluations

Batch Evaluation Pattern

Annotate Spans

Update Annotations

Update Metadata

Method 1: Direct Field Columns

Method 2: Patch Document Column

Method 3: Combined Approach

Type Handling

Response Structure

Delete Spans

Export Spans

Export to Parquet