Output Parser

processing.output-parser Processing v0.1.0

Turns an LLM's raw text answer into validated structured JSON. Strips a ```json code fence, pulls the first {…} / […] out of surrounding prose, and JSON-parses it; in schema mode it also validates the result against a JSON Schema. Emits { parsed, valid } (plus an error when invalid) — pure, no model call.

The Output Parser step on the Studio canvas
The Output Parser 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 Output Parser (it lives under Processing). 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.

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

Wired up in the builder

Output Parser 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.

Output Parser wired into a runnable workflow in the Studio builder
Output Parser 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 Output Parser node's settings in the Studio builder
The settings for Output Parser, showing the values from the flow above.

Ports

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
InputinputInput
OutputoutputParsed

How data flows through it

Output Parser consumes the content of the incoming envelope — when it is fed directly by a trigger, the trigger’s wrapper is unwrapped at the node boundary so the node sees the actual data, not the metadata shell. Its output becomes the payload for the next node, while the envelope (trace ids, correlation, binary refs) rides along untouched. In the Runs view you always see the whole envelope for both sides of this node.

Expressions in the config

None of this node’s properties are string-typed, so {{ }} expressions don’t apply here — JSON- and code-typed fields are always taken 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 (Output Parser) works as well as the exact type id (processing.output-parser).

In the Copilot panel (or any connected AI):

add a output parser node after the trigger

As a step in a create_chain_workflow call:

{"type":"Output Parser","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": "Output Parser" } } }'

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 Output Parser 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 Output Parser 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
Text field
inputField
field "" Dot-path to the raw answer text. Blank = the whole payload (coerced to a string).
Mode
mode
select "json" json parses the answer to any JSON value; schema also validates the parsed value against a JSON Schema.
jsonschema
Schema
schema
json {"type":"object"} JSON Schema the parsed value must satisfy in schema mode.
Shown when (mode ?? "json") === "schema"
Error on invalid
errorOnInvalid
boolean false When on, throw a coded error if the text cannot be parsed (or fails the schema); when off, output { parsed: null, error } instead.

Related nodes

The rest of the Processing 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.