WebSocket Trigger

input.websocket Input v0.1.0

Accepts a persistent WebSocket connection; each inbound message starts the workflow, and data sent to its feedback input is pushed back to connected clients.

The WebSocket Trigger step on the Studio canvas
The WebSocket Trigger step as it appears on the Studio canvas — input pins on the left, output ports on the right.

Finding it in the library

Search the builder's node library for WebSocket Trigger (it lives under Input). A single click opens the in-editor docs panel shown here — description, ports, and every property, without leaving the canvas. Double-click (or drag) to add it to the workflow.

WebSocket Trigger in the node library, with the in-editor docs panel open
The library entry and the in-editor docs panel for WebSocket Trigger — the same reference this page is generated from.

Wired up in the builder

WebSocket Trigger in a real, runnable flow — captured live from the Studio editor, exactly as it looks on your canvas. This is the same workflow used for the example input & output below.

WebSocket Trigger wired into a runnable workflow in the Studio builder
WebSocket Trigger wired into a runnable flow — input on the left, output on the right.

How it’s configured

The node’s settings as the builder shows them — every field laid out with real values. In the Studio these are edited on the node: click the chevron on the divider under its ports to open them.

The WebSocket Trigger node's settings in the Studio builder
The settings for WebSocket Trigger, showing the values from the flow above.

Ports

This is a trigger — it starts runs and takes no input wire.

Ports are the node’s contract with its neighbours. In the editor a port label renders bold when wired and italic when optional; ports accept attachment carriers rather than data wires.

DirectionPortLabelWhat flows through it
OutputoutputMessage

How data flows through it

As a trigger, WebSocket Trigger starts runs — it takes no input wire. What it emits is the request wrapper: the event’s body becomes the payload, and the wrapper carries the event metadata around it (for an HTTP-style trigger that’s headers.*, request.method, request.path and query). Downstream nodes consume the content — the wrapper is unwrapped at each node boundary, and expression roots like {{ headers.x }} still resolve against the wrapper when you need the metadata. See Runs & run data for the envelope model.

Expressions in the config

String-typed properties accept {{ }} expressions evaluated against the incoming item at run time — e.g. {{ $json.customer.email }}. On this node that’s path, subprotocol, authUser, authPassword, authHeaderName, authHeaderValue, authToken, ipAllowlist. JSON- and code-typed fields never interpolate — they are passed through literally.

Build it with AI

Every node in this reference is reachable through Flowdrome’s AI Copilot and the MCP tools — say what you want, and the graph surgery happens server-side. Node types resolve fuzzily, so the catalog label (WebSocket Trigger) works as well as the exact type id (input.websocket).

In the Copilot panel (or any connected AI):

create a workflow that starts with websocket trigger and logs the result

As a step in a create_chain_workflow call:

{"type":"WebSocket Trigger","config":{}}
Raw MCP call — add this node to a workflow with add_node
curl -s -X POST http://localhost:4800/mcp -H "content-type: application/json" -d '{ "jsonrpc": "2.0", "id": "1", "method": "tools/call", "params": { "name": "add_node", "arguments": { "workflowId": "<id>", "type": "WebSocket Trigger" } } }'

Example input & output

Captured from a real test run of the workflow above — this is what the Runs view shows after pressing Test workflow.

Input — what the node received

The WebSocket Trigger node's input envelope in the run data viewer
The input envelope in the Runs view — Flowdrome always shows the whole envelope, with the payload inside body.

Output — what the node produced

The WebSocket Trigger node's output envelope in the run data viewer
The output envelope after the step ran.

Property reference

Every setting, with its type and default — the same fields shown configured above.

PropertyTypeDefaultDescription
Path
path
string "/ws" URL path the WebSocket server listens on.
Subprotocol
subprotocol
string Optional WebSocket subprotocol to negotiate.
Heartbeat (seconds)
heartbeatSeconds
int 30 Ping interval that keeps idle connections alive.
Max connections
maxConnections
int Optional cap on concurrent connections.
Max message (bytes)
maxPayloadBytes
int 1048576 Largest inbound WebSocket message this trigger accepts — an oversized message closes the socket (code 1009). 0 = unlimited (a 128 MB safety wall still applies).
Authentication
authType
select "none" Require credentials on incoming requests: Basic (user/password), Header (exact header match), Bearer (Authorization: Bearer <token>). Checked before rate limits — rejected requests never reach the workflow.
basicbearerheadernone
Credential
credentialId
credential "" Use a stored credential for this connection — its fields are filled in at run start. Pick "None" to enter the connection details manually.
accepts credential templates: http-basichttp-headerhttp-bearer
Shown when String(authType ?? "none") !== "none"
User
authUser
string Expected Basic-auth user name.
Shown when String(authType ?? "none") === t
Password
authPassword
string Expected Basic-auth password.
Shown when String(authType ?? "none") === t
Header name
authHeaderName
string Name of the header that must carry the shared value, e.g. x-api-key (case-insensitive).
Shown when String(authType ?? "none") === t
Header value
authHeaderValue
string Exact value the header must carry.
Shown when String(authType ?? "none") === t
Token
authToken
string Expected bearer token — requests must send Authorization: Bearer <token>.
Shown when String(authType ?? "none") === t
IP allowlist
ipAllowlist
string "" Comma-separated client IPs or CIDR ranges allowed to call this trigger. Empty = allow all. Rejections are 403 before anything else runs.
Rate limit (req/s)
rateLimitRps
double 0 Per-client-IP sustained request rate for this trigger. 0 = no rate limit (the default). For internet-exposed apps, prefer rate limiting at a fronting reverse proxy (docs/ingress-guards-design.md).
Rate limit burst
rateLimitBurst
int 0 How many requests a client may send back-to-back before the per-second rate applies. 0 = automatic (2× the rate).
Shown when (showIf === undefined || showIf(c)) && Number(rateLimitRps ?? 0) > 0

Related nodes

The rest of the Input group — the same folder you’d scan in the editor’s library.

This page is generated from the node registry by gen-node-docs.mjs on every site build — ports, properties, defaults and visibility rules cannot drift from the code. The screenshots and example data are captured from a live Flowdrome by npm run shots:nodes and npm run gen:examples.