Import this as Grafana dashboard

fastapi_prom_grafana_dashboard.json

{
  "title": "FastAPI Prometheus Metrics Dashboard",
  "timezone": "browser",
  "refresh": "10s",
  "schemaVersion": 30,
  "version": 1,
  "panels": [
    {
      "type": "timeseries",
      "title": "Request Rate (Total)",
      "targets": [
        {
          "expr": "sum(rate(http_requests_total[1m])) by (handler)",
          "legendFormat": "{{handler}}",
          "refId": "A"
        }
      ],
      "datasource": "Prometheus",
      "gridPos": {
        "x": 0,
        "y": 0,
        "w": 12,
        "h": 8
      }
    },
    {
      "type": "timeseries",
      "title": "Latency (95th Percentile)",
      "targets": [
        {
          "expr": "histogram_quantile(0.95, sum(rate(http_request_duration_seconds_bucket[1m])) by (le, handler))",
          "legendFormat": "{{handler}}",
          "refId": "A"
        }
      ],
      "datasource": "Prometheus",
      "gridPos": {
        "x": 12,
        "y": 0,
        "w": 12,
        "h": 8
      }
    },
    {
      "type": "timeseries",
      "title": "Request Size (Bytes/sec)",
      "targets": [
        {
          "expr": "rate(http_request_size_bytes_sum[1m])",
          "legendFormat": "{{handler}}",
          "refId": "A"
        }
      ],
      "datasource": "Prometheus",
      "gridPos": {
        "x": 0,
        "y": 8,
        "w": 12,
        "h": 8
      }
    },
    {
      "type": "timeseries",
      "title": "Response Size (Bytes/sec)",
      "targets": [
        {
          "expr": "rate(http_response_size_bytes_sum[1m])",
          "legendFormat": "{{handler}}",
          "refId": "A"
        }
      ],
      "datasource": "Prometheus",
      "gridPos": {
        "x": 12,
        "y": 8,
        "w": 12,
        "h": 8
      }
    }
  ],
  "annotations": {
    "list": [
      {
        "builtIn": 1,
        "type": "dashboard",
        "name": "Annotations & Alerts",
        "enable": true
      }
    ]
  }
}