Kibana / Custom Visualization via Vega - Heatmap

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "title": "Heatmap: Avg duration per method and status_code",
  "data": {
    "url": {
      "%context%": true,
      "%timefield%": "@timestamp",
      "index": "logs-*",
      "body": {
        "size": 0,
        "aggs": {
          "combo": {
            "composite": {
              "size": 2000,
              "sources": [
                { "method": { "terms": { "field": "method" } } },
                { "status": { "terms": { "field": "status_code" } } }
              ]
            },
            "aggs": {
              "avg_duration": { "avg": { "field": "duration_ms" } },
              "p95": { "percentiles": { "field": "duration_ms", "percents": [95] } }
            }
          }
        }
      }
    },
    "format": { "property": "aggregations.combo.buckets" }
  },

  "transform": [
    { "calculate": "datum.key.method", "as": "method" },
    { "calculate": "toNumber(datum.key.status)", "as": "status" },
    { "calculate": "datum.avg_duration.value", "as": "duration" },
    { "calculate": "datum['p95']['values']['95.0']", "as": "p95" },
    { "filter": "isValid(datum.duration)" }
  ],

  "mark": {
    "type": "rect",
    "stroke": "#ffffff",
    "strokeWidth": 0.8
  },

  "encoding": {
    "x": {
      "field": "method",
      "type": "nominal",
      "title": "Method",
      "sort": ["GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"]
    },

    "y": {
      "field": "status",
      "type": "ordinal",
      "title": "Status code",
      "sort": "ascending"
    },

    "color": {
      "field": "duration",
      "type": "quantitative",
      "title": "Avg duration (ms)",
      "scale": {
        "type": "sqrt",
        "scheme": "redyellowgreen",
        "reverse": true
      }
    },

    "tooltip": [
      { "field": "method", "title": "Method" },
      { "field": "status", "title": "Status code" },
      { "field": "duration", "title": "Avg", "format": ".2f" },
      { "field": "p95", "title": "p95 (ms)", "format": ".2f" }
    ]
  }
}