The /generate_vega_chart endpoint analyzes your question and data to produce an optimized visualization specification. It intelligently selects the appropriate chart type, colors, and layout based on your data characteristics and question intent.

Key Features

Automatic chart selection: Chooses the best visualization type based on your data
Embedded data: Results are included in the specification for immediate rendering

Example

Response will be a Vega spec you could render with the Vega library. For example:

{
  "question": "Show me total payments by customer state",
  "sql": "SELECT customer_state, SUM(payment_value) AS total_payment_value FROM orders GROUP BY customer_state ORDER BY total_payment_value DESC",
  "threadId": "75ab23c8-9124-4560-a125-fbe7e321dcba"
}

Response:

{
    "id": "a9597146-03ee-4de7-bcd6-57d71bffe86a",
    "vegaSpec": {
        "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
        "config": {
            "mark": {
                "tooltip": true
            },
            "font": "Roboto, Arial, Noto Sans, sans-serif",
            "padding": {
                "top": 30,
                "bottom": 20,
                "left": 0,
                "right": 0
            },
            "title": {
                "color": "#262626",
                "fontSize": 14
            },
            "axis": {
                "labelPadding": 0,
                "labelOffset": 0,
                "labelFontSize": 10,
                "gridColor": "#d9d9d9",
                "titleColor": "#434343",
                "labelColor": "#65676c",
                "labelFont": " Roboto, Arial, Noto Sans, sans-serif"
            },
            "axisX": {
                "labelAngle": -45
            },
            "line": {
                "color": "#1570EF"
            },
            "bar": {
                "color": "#1570EF"
            },
            "legend": {
                "symbolLimit": 15,
                "columns": 1,
                "labelFontSize": 10,
                "labelColor": "#65676c",
                "titleColor": "#434343",
                "titleFontSize": 14
            },
            "range": {
                "category": [
                    "#7763CF",
                    "#444CE7",
                    "#1570EF",
                    "#0086C9",
                    "#3E4784",
                    "#E31B54",
                    "#EC4A0A",
                    "#EF8D0C",
                    "#EBC405",
                    "#5381AD"
                ],
                "ordinal": [
                    "#7763CF",
                    "#444CE7",
                    "#1570EF",
                    "#0086C9",
                    "#3E4784",
                    "#E31B54",
                    "#EC4A0A",
                    "#EF8D0C",
                    "#EBC405",
                    "#5381AD"
                ],
                "diverging": [
                    "#7763CF",
                    "#444CE7",
                    "#1570EF",
                    "#0086C9",
                    "#3E4784",
                    "#E31B54",
                    "#EC4A0A",
                    "#EF8D0C",
                    "#EBC405",
                    "#5381AD"
                ],
                "symbol": [
                    "#7763CF",
                    "#444CE7",
                    "#1570EF",
                    "#0086C9",
                    "#3E4784",
                    "#E31B54",
                    "#EC4A0A",
                    "#EF8D0C",
                    "#EBC405",
                    "#5381AD"
                ],
                "heatmap": [
                    "#7763CF",
                    "#444CE7",
                    "#1570EF",
                    "#0086C9",
                    "#3E4784",
                    "#E31B54",
                    "#EC4A0A",
                    "#EF8D0C",
                    "#EBC405",
                    "#5381AD"
                ],
                "ramp": [
                    "#7763CF",
                    "#444CE7",
                    "#1570EF",
                    "#0086C9",
                    "#3E4784",
                    "#E31B54",
                    "#EC4A0A",
                    "#EF8D0C",
                    "#EBC405",
                    "#5381AD"
                ]
            },
            "point": {
                "size": 60,
                "color": "#1570EF"
            }
        },
        "title": "Total Payments by Customer State",
        "data": {
            "values": [
                {
                    "customer_state": "PR",
                    "total_payment_value": 811156.379999998
                },
                {
                    "customer_state": "BA",
                    "total_payment_value": 616645.8200000012
                },
                {
                    "customer_state": "RJ",
                    "total_payment_value": 2144379.68999999
                },
                {
                    "customer_state": "SE",
                    "total_payment_value": 75246.25
                },
                {
                    "customer_state": "TO",
                    "total_payment_value": 61485.32999999993
                },
                {
                    "customer_state": "AP",
                    "total_payment_value": 16262.8
                },
                {
                    "customer_state": "SC",
                    "total_payment_value": 623086.43
                },
                {
                    "customer_state": "PA",
                    "total_payment_value": 218295.85
                },
                {
                    "customer_state": "MT",
                    "total_payment_value": 187029.28999999986
                },
                {
                    "customer_state": "AL",
                    "total_payment_value": 96962.06000000003
                },
                {
                    "customer_state": "RN",
                    "total_payment_value": 102718.13
                },
                {
                    "customer_state": "AC",
                    "total_payment_value": 19680.62
                },
                {
                    "customer_state": "GO",
                    "total_payment_value": 350092.3100000009
                },
                {
                    "customer_state": "ES",
                    "total_payment_value": 325967.55000000045
                },
                {
                    "customer_state": "AM",
                    "total_payment_value": 27966.93
                },
                {
                    "customer_state": "MS",
                    "total_payment_value": 137534.84000000003
                },
                {
                    "customer_state": "RR",
                    "total_payment_value": 10064.62
                },
                {
                    "customer_state": "PI",
                    "total_payment_value": 108523.97000000003
                },
                {
                    "customer_state": "SP",
                    "total_payment_value": 5998226.959999885
                },
                {
                    "customer_state": "MG",
                    "total_payment_value": 1872257.2600000093
                },
                {
                    "customer_state": "DF",
                    "total_payment_value": 355141.0799999998
                },
                {
                    "customer_state": "MA",
                    "total_payment_value": 152523.02000000002
                },
                {
                    "customer_state": "RS",
                    "total_payment_value": 890898.5399999967
                },
                {
                    "customer_state": "CE",
                    "total_payment_value": 279464.0300000001
                },
                {
                    "customer_state": "PE",
                    "total_payment_value": 324850.4399999999
                },
                {
                    "customer_state": "PB",
                    "total_payment_value": 141545.7199999999
                },
                {
                    "customer_state": "RO",
                    "total_payment_value": 60866.2
                }
            ]
        },
        "mark": {
            "type": "bar"
        },
        "width": "container",
        "height": "container",
        "autosize": {
            "type": "fit",
            "contains": "padding"
        },
        "encoding": {
            "x": {
                "field": "customer_state",
                "type": "nominal",
                "title": "Customer State"
            },
            "y": {
                "field": "total_payment_value",
                "type": "quantitative",
                "title": "Total Payment Value"
            },
            "color": {
                "field": "customer_state",
                "type": "nominal",
                "title": "Customer State",
                "scale": {
                    "range": [
                        "#7763CF",
                        "#444CE7",
                        "#1570EF",
                        "#0086C9",
                        "#3E4784",
                        "#E31B54",
                        "#EC4A0A",
                        "#EF8D0C",
                        "#EBC405",
                        "#5381AD"
                    ]
                }
            },
            "opacity": {
                "condition": {
                    "param": "hover",
                    "value": 1
                },
                "value": 0.3
            }
        },
        "params": [
            {
                "name": "hover",
                "select": {
                    "type": "point",
                    "on": "mouseover",
                    "clear": "mouseout",
                    "fields": [
                        "customer_state"
                    ]
                }
            }
        ]
    },
    "threadId": "bfbef4db-5bb4-4133-a65f-9dd813569727"
}

Try copying this spec into the Vega Editor and you'll see a chart like this:

Error Handling

If chart generation fails, you'll receive an error response:

{
  "id": "c4f82c31-a40d-4b8e-9e5f-c1d8a742db55",
  "code": "INVALID_SQL",
  "error": "Unable to generate chart: SQL query does not return valid data for visualization"
}

Supported Chart Types

Check Wren AI / Generate Chart for reference.

200Successfully generated Vega specification

400Bad request or specification generation error