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.