Free online tool

Community Structure Explorer

Find groups of closely connected nodes in a network. Adjust the grouping settings and download each node's group.

Works on your deviceNo account neededGraph JSON / SVG / PNG / CSVOpen workspace ↓

Are detected network communities objectively correct groups?

Community detection proposes a partition based on graph structure. Louvain searches for high modularity, and its result depends on resolution, initialization and connections. Compare seeds or resolutions, inspect the colored groups and export membership data together with the reported modularity.

Make the connections.

On your device

Diagram title

Import graph JSON

Use directed: true or false, a nodes array with unique IDs, and edges with source and target IDs.

{
  "directed": false,
  "nodes": [
    {
      "id": "A",
      "label": "Village",
      "tags": [
        "home"
      ],
      "notes": "Starting point",
      "x": 140,
      "y": 200
    },
    {
      "id": "B",
      "label": "Forest",
      "tags": [
        "outdoors"
      ],
      "x": 380,
      "y": 90
    },
    {
      "id": "C",
      "label": "Bridge",
      "x": 380,
      "y": 310
    },
    {
      "id": "D",
      "label": "Castle",
      "x": 660,
      "y": 200
    },
    {
      "id": "E",
      "label": "Harbour",
      "x": 900,
      "y": 310
    }
  ],
  "edges": [
    {
      "id": "ab",
      "source": "A",
      "target": "B",
      "weight": 2
    },
    {
      "id": "ac",
      "source": "A",
      "target": "C",
      "weight": 6
    },
    {
      "id": "bc",
      "source": "B",
      "target": "C",
      "weight": 1
    },
    {
      "id": "bd",
      "source": "B",
      "target": "D",
      "weight": 7
    },
    {
      "id": "cd",
      "source": "C",
      "target": "D",
      "weight": 2
    },
    {
      "id": "de",
      "source": "D",
      "target": "E",
      "weight": 3
    }
  ]
}

Layout algorithmFlow directionNode spacing

Directed connectionsShow edge weights5 nodes · 6 connections

Edit nodes & connections ↓

Drag a node to move it. Drag blank space to pan.

Keyboard: focus a node and use arrow keys to move it; hold Shift for larger steps. Labels and notes are available in the editor below.

Find network communities

ResolutionRandom seedUse edge weights

Nodes & notes

Search nodes, notes or tagsChoose node (5 matches)

Deleting a node also deletes its connections. Undo restores both. Keep at least one node.

Connections

Three simple steps

How to use Community Structure Explorer

Open a graph project or edit nodes and connections in the workspace.
Explore the graph and choose the relevant analysis or layout controls.
Export the diagram, data tables or an editable project.

Common questions

Good to know

Understand the result.
Keep the original.

Is this tool free, and are my files uploaded?

This tool is free with no account required. The work happens in your browser. Your input and files are not sent to a processing server.

What are the limits and details?

Louvain is a heuristic, and its communities are not ground-truth categories. Weights represent nonnegative connection strengths. Isolated nodes are retained, and modularity is undefined for an edgeless graph. Use the same seed and graph order for repeatable results.

Limits: 500 nodes, 2,000 edges and 500,000 project characters. Expensive operations run in a cancellable 30-second browser worker.

Are detected network communities objectively correct groups?

Make the connections.

Find network communities

Nodes & notes

Connections

How to use Community Structure Explorer

Good to know

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