# API workflow nodes

> Exchange data with external systems over OSC and HTTP. Listen for OSC messages, serve REST endpoints, and send or poll HTTP requests.

Use these nodes to exchange data with external systems. Listener and server nodes open network ports, so configure authentication and exposure deliberately. Choose a node OSC Listener : listen for open sound control (osc) messages on a udp port REST Server : expose selected workflow values and triggers as http endpoints HTTP Request : send one http request when another node triggers it HTTP Query : fetch and refresh data from an http endpoint OSC Listener Listen for Open Sound Control (OSC) messages on a UDP port. What you see in the editor The card header reads OSC Server , even though this node is listed and referred to elsewhere as OSC Listener . Set Port : accepted values are 1024–65535; a lower value shows a Too small: expected number to be >=1024 error and the node won't start. Then use Add Path to add each OSC path the workflow should accept. Each path's editor popover reminds you of the supported syntax: :param for a single named segment, * to match one segment, and ** to match many. For a path such as /scene/:name , the node creates an event for that path and makes each :name -style segment available as its own output. Only :param segments produce an output: * and ** wildcards match but don't expose a value. Connections Kind Label What it provides Output events One per configured path Fires when an incoming OSC address matches that path. Outputs One per :param in the path The latest value received for that named segment. Output Arg 1 The first OSC argument from the matched message, regardless of how many arguments it carried. Example Add /scene/:name , send /scene/main from a test client, and use the resulting event and name value downstream. REST Server Expose selected workflow values and triggers as HTTP endpoints. What you see in the editor Set Port : accepted values are 1024–65535. Rate Limit is a preset dropdown ( 10 reqs / min , 100 reqs / min , 1000 reqs / min , or Off ), not a custom number. Add one or more Bearer Tokens to require that token on every endpoint (GET and POST alike; there's no per-endpoint auth control). Configure both before exposing the server to another system. Use Add Endpoint to enter a Path and choose GET or POST . A GET endpoint returns its connected value. A POST endpoint updates its output and fires an event. Connections Kind Label What it provides Input One per GET endpoint The value returned by that endpoint. Output One per POST endpoint The latest request body. Output event One per POST endpoint Fires when a request reaches that endpoint. Example Create an authenticated GET /status endpoint for a non-sensitive workflow value and test it from the intended network. See Expose a small authenticated REST endpoint from a workflow for a full walkthrough, including bearer-token rotation and restart behavior. HTTP Request Send one HTTP request when another node triggers it. What you see in the editor Enter URL . Choose Method from GET , POST , PUT , PATCH , DELETE , HEAD , or OPTIONS , and Content Type from JSON , JSON (UTF-8) , Form URL Encoded , Octet Stream , or Text : both are dropdowns, not free text. Set Timeout (ms) from 0 to 300000 (default 30000). Under Authentication , choose None , Bearer Token , or Basic Auth . Select stored Secrets for tokens and passwords rather than typing credentials into the workflow. Use this node for one-shot requests. Use HTTP Query for automatic polling. Connections Kind Label What it provides Input event Trigger Sends a request using the values configured on the card. Input event Request Object Sends a request with event-provided overrides. Inputs URL , Method , Headers , Body Override or supply request values. Output events onSuccess , onError Continue according to the result. Outputs Body , Full Response , Error , Status Code Inspect the latest response. Example Connect a Button to Trigger , make a harmless read request, and display Status Code while testing. See Call an HTTP endpoint from a workflow for a full walkthrough, including timeout and error-handling behavior. HTTP Query Fetch and refresh data from an HTTP endpoint. What you see in the editor Enter URL . Choose Method from GET , POST , PUT , PATCH , DELETE , or HEAD (no OPTIONS here, unlike HTTP Request ), Content Type from the same five options as HTTP Request, Timeout (ms) from 1000–300000 (default 30000), and Authentication . Choose a Retry Strategy : Exponential Backoff (capped by Max Backoff (ms) , 1000–600000, default 60000) or Fixed Interval ( Retry Interval (ms) , 500–60000, default 5000). Toggle Infinite Retries , or set Max Retries (0–100, default 3). Only failed requests with a 5xx status or a timeout are retried; a 4xx response is not. Refetch Interval is a switch that's on by default : with it on the node polls automatically every Interval (ms) (1000–3,600,000, default 10000) even if you never touch this section. Turn it off for a query that should only run once or on demand. Set Cache Mode : Never Cache , Cache Until Retry Fails (default), or Cache Until Success , and optionally enable Expire Cache After Timeout with an Expire After (ms) value (1000–86,400,000). The status panel shows the current state, status code, error, and a preview of the last response. Use Refetch to fetch now. Retry becomes available after an error. Connections Kind Label What it provides Input Enabled Stops all fetching when false. Input event Invalidate Starts an immediate fetch. Inputs URL , Headers , Params , Body Supply request values. Output events onSuccess , onError , onSettled Respond when a request completes. Outputs Status , Data , Error , isLoading , isError , isSuccess , Status Code Use the latest query state and response. Example Poll a read-only status endpoint and connect isSuccess and Data to the workflow’s display logic.