Features

Sharing & export

Plain JSON, a self-contained link, or an image.

Feature	Details
Autosave	Written to local storage shortly after you stop editing; the toolbar shows Saved or Saving…
Export JSON	Downloads the canonical format — diffable, scriptable, version-controllable
Import JSON	Validated on load; unusable parts are dropped rather than breaking the canvas
Share link	Compresses the whole diagram into the URL — no server involved
Export PNG	Renders the canvas at 2× on a white background

The file format

One object with a name, a list of nodes and a list of edges. Anything Nautilus does not recognise is dropped on import, so hand-written and script-generated files are safe to load.

{
  "name": "Payments platform",
  "nodes": [
    {
      "id": "api",
      "type": "nautilusNode",
      "position": { "x": 120, "y": 40 },
      "data": {
        "label": "Payments API",
        "icon": "api_server",
        "color": "green",
        "description": "Authorises and captures charges",
        "sim": {
          "capacity": 4000,
          "replicas": 6,
          "latencyMs": 25,
          "errorRate": 0.001
        }
      }
    }
  ],
  "edges": [
    {
      "id": "e1",
      "source": "api",
      "target": "db",
      "type": "deletableEdge",
      "label": "cache miss",
      "data": { "sim": { "share": 0.15, "fanout": 1 } }
    }
  ],
  "sim": {
    "requestsPerSecond": 10000,
    "timeoutMs": 500,
    "payloadKb": 8,
    "targetUtilization": 0.7,
    "burstFactor": 2
  }
}

Node fields

Field	Meaning
id	Unique within the file. Duplicates are dropped on import.
type	`nautilusNode`
position	Canvas coordinates, { x, y }.
data.label	Name shown on the node.
data.icon	Key from the icon reference.
data.color	default \| blue \| green \| red \| yellow \| purple \| orange
data.description	Free text shown on the node and read by the AI assistant.
data.sim	Load model — see below. Optional.

Simulation fields

Field	Where	Default
sim.capacity	node — requests/second one replica serves	unbounded
sim.replicas	node — identical instances	1
sim.latencyMs	node — service time before queueing	20
sim.errorRate	node — baseline failure rate, 0–1	0
sim.down	node — failure injection; the node serves nothing	absent
sim.costPerHour	node — price of one replica per hour	0
sim.hitRate	node — share answered here, not forwarded, 0–1	0
sim.queue	node — buffers past capacity instead of dropping	auto by icon
sim.share	edge — fraction of requests taking this edge, 0–1	1
sim.fanout	edge — calls made per request	1
sim.async	edge — fire-and-forget; latency past it leaves the request path	auto into queues

These survive export, import, share links and autosave, so a diagram carries its capacity model with it. Missing fields fall back to the defaults above rather than to zero.

The top-level sim object holds the playground parameters — offered load, timeout budget, payload size, target utilisation and burst factor — so a shared link reproduces the exact scenario instead of resetting to the defaults.

Edge fields

Field	Meaning
id	Unique within the file.
source / target	Node ids. Edges pointing at a missing node are dropped on import.
type	`deletableEdge`
label	Optional text rendered on the connection.
animated	Optional boolean, purely visual.
data.sim	Routing model — share and fanout.

Share links are unlisted, not private

The diagram is encoded in the URL itself. Anyone holding the link — or reading a referrer header or a proxy log — has the diagram. Don't share internal architecture this way; export a file instead.