OpenBB-finance/OpenBB · error · ValueError

Failed to convert DataFrame to JSON

Error message

Failed to convert DataFrame to JSON

What it means

Thrown by the OmniWidgetResponseModel model_validator when content is a pandas DataFrame and DataFrame.to_json(orient='records') fails (or its output cannot be re-parsed with json.loads). The validator converts tabular data into a list of records for the widget layer; any serialization failure is re-raised as this ValueError.

Source

Thrown at openbb_platform/extensions/platform_api/openbb_platform_api/response_models.py:252

        if content.__class__.__name__ == "Figure":
            values.parse_as = "chart"
            try:
                content = content.to_json()
            except Exception as e:
                raise ValueError("Failed to convert chart to JSON") from e
            values.content = content
        elif isinstance(content, dict) and "layout" in content and "data" in content:
            values.parse_as = "chart"
        elif isinstance(content, list) and all(
            isinstance(item, dict) for item in content
        ):
            values.parse_as = "table"
        elif isinstance(content, pd.DataFrame):
            values.parse_as = "table"
            try:
                content = json.loads(content.to_json(orient="records"))
            except Exception as e:
                raise ValueError("Failed to convert DataFrame to JSON") from e
            values.content = content
        elif isinstance(content, dict) and all(
            isinstance(v, list) for v in content.values()
        ):
            values.parse_as = "table"
            try:
                df = pd.DataFrame(content)
                content = json.loads(df.to_json(orient="records"))
            except Exception as e:
                raise ValueError(
                    "Failed to convert dictionary of lists to list of records"
                ) from e
            values.content = content
        elif isinstance(content, str) and content.strip():  # pylint: disable=R0916
            try:
                content = json.loads(content)
            except json.JSONDecodeError:
                # Remove trailing commas in objects and arrays

View on GitHub (pinned to 3e071fcc2c)

Solutions

1. Inspect e.__cause__ from the raised ValueError to find the offending column/value.
2. Convert problem columns before constructing the model: df = df.convert_dtypes() or df = df.astype(object).where(df.notna(), None).
3. Pass the records yourself: content=df.to_json(orient='records') as a pre-serialized string, or content=json.loads(df.to_json(orient='records')).
4. Drop or stringify non-serializable object columns (e.g. columns holding nested Data models).

Example fix

# before
resp = OmniWidgetResponseModel(content=df_with_object_cols)

# after
records = json.loads(df.to_json(orient="records"))
resp = OmniWidgetResponseModel(content=records)

records = json.loads(df.to_json(orient="records"))
resp = OmniWidgetResponseModel(content=records)

import pandas as pd
def is_serializable_dataframe(obj) -> bool:
    if not isinstance(obj, pd.DataFrame):
        return False
    try:
        obj.to_json(orient="records")
        return True
    except Exception:
        return False

try:
    resp = OmniWidgetResponseModel(content=df)
except ValueError as e:
    if "DataFrame to JSON" in str(e):
        df = df.convert_dtypes()
        resp = OmniWidgetResponseModel(content=json.loads(df.to_json(orient="records")))
    else:
        raise

When it happens

Trigger: Constructing OmniWidgetResponseModel(content=df) where df contains values pandas to_json cannot encode, or where the DataFrame uses non-string-MAX pathologies (e.g. mixed-type object columns with custom classes, Decimal, or unhashable objects) that break the JSON encoder.

Common situations: Handing a raw provider response DataFrame containing Data/BaseModel objects in cells; DataFrames built from records with numpy scalars in object columns; pandas version differences in to_json handling of NaN and mixed dtypes.

Related errors

• Failed to convert chart to JSON
• Failed to convert dictionary of lists to list of records
• At least one extension type must be selected.
• Incorrect email or password
• Charting is not installed. Please install `openbb-charting`.

AI-assisted analysis of OpenBB-finance/OpenBB@3e071fcc2c (2026-08-14). Data as JSON: /api/errors/67fe8f41394a456d. Report an issue: GitHub.