Chart.js example

chart.json

{
  "type": "line",
  "data": {
    "labels": [ "", "", "", "", "", "", "", "" ],
    "datasets": [
      {
        "label": "comments",
        "borderColor": "blue",
        "yAxisID": "A",
        "data": [ 0, 1, 1, 1, 2, 3, 4, 4 ],
        "fill": false,
        "borderWidth": 1
      },
      {
        "label": "retweets",
        "borderColor": "green",
        "backgroundColor": "#ff8c00",
        "pointBorderColor": "#ff8c00",
        "yAxisID": "B",
        "data": [ 80, 261, 357, 475, 501, 514, 527, 535 ],
        "pointRadius": [ 0, 0, 5, 0, 0, 0, 0, 0 ],
        "fill": false,
        "borderWidth": 1
      }
    ]
  },
  "options": {
    "legend": {
      "position": "right",
      "labels": {
        "boxWidth": 5,
        "fontSize": 8,
        "padding": 5
      }
    },
    "layout": {
      "padding": {
        "bottom": -20
      }
    },
    "elements": {
      "point": {
        "radius": 0
      }
    },
    "scales": {
      "xAxes": [
        {
          "gridLines": {
            "color": "transparent"
          }
        }
      ],
      "yAxes": [
        {
          "id": "A",
          "position": "left",
          "gridLines": {
            "color": "transparent",
            "tickMarkLength": 5
          },
          "ticks": {
            "min": 0,
            "max": 6,
            "maxTicksLimit": 1,
            "precision": 0,
            "fontSize": 8,
            "fontColor": "blue",
          }
        },
        {
          "id": "B",
          "position": "right",
          "gridLines": {
            "color": "transparent",
            "tickMarkLength": 5
          },
          "ticks": {
            "min": 0,
            "max": 535,
            "maxTicksLimit": 1,
            "fontSize": 8,
            "fontColor": "green",
          }
        }
      ]
    },
    "annotation": {
      "annotations": [
        {
          "type": "box",
          "yScaleID": "A",
          "yMin": 0,
          "yMax": 3,
          "backgroundColor": "#E0E0FF66",
          "borderColor": "transparent"
        }
      ]
    }
  }
}