Write File

storage.write-file Storage v0.1.0

Writes workflow data to a file — pretty JSON, raw text, or decoded base64 bytes — with optional append and parent-directory creation. A list on the wire is N records, and the File path decides where they land: a literal path is ONE file (the batch as a single document, or one joined append), while a path holding {{ }} that varies per record writes one file per record. Two records resolving to the SAME file is refused with IO_WRITE_PATH_COLLISION before a single byte is written — overwriting would keep only the last and destroy the rest — so make the path unique (e.g. add {{ $itemIndex }}) or turn on Append to land them in that one file, in order. Every record is planned before the first write, and an empty list writes nothing.

The Write File step on the Studio canvas — The **Write File** 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 Write File (it lives under Storage). 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.

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

Wired up in the builder

Write File 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.

Write File wired into a runnable workflow in the Studio builder — **Write File** 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 Write File node's settings in the Studio builder — The settings for **Write File**, 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.

Direction	Port	Label	What flows through it
Input	`input`	Input
Output	`output`	Payload

How data flows through it

Write File 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

String-typed properties accept {{ }} expressions evaluated against the incoming item at run time — e.g. {{ $json.customer.email }}. On this node that’s path. 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 (Write File) works as well as the exact type id (storage.write-file).

In the Copilot panel (or any connected AI):

add a write file node after the trigger

As a step in a create_chain_workflow call:

{"type":"Write File","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": "Write File" } } }'

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 Write File 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 Write File 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.

Property	Type	Default	Description
File path `path`	`string`	`—`	Absolute path of the file to write. A {{ }} template resolves against THIS record, so a list on the input writes ONE FILE PER RECORD (e.g. C:/out/{{ $json.id }}.json); a literal path writes the whole batch as one file. If two records resolve to the SAME path the node fails with IO_WRITE_PATH_COLLISION before writing anything — make the path unique (add {{ $itemIndex }}), or turn on Append to add them all to that one file.
Content `contentMode`	`select`	`"json"`	JSON pretty-prints the value; Text writes a string as-is (errors on non-strings); Base64 decodes a base64 string to raw bytes. For a batch landing in ONE file, JSON writes the array of the records' values and Text/Base64 write them joined. `base64jsontext`
Input field `inputField`	`field`	`""`	Dot-path to the value to write, read from THIS record. Leave blank to write the record itself.
Append `append`	`boolean`	`false`	Append to the file instead of overwriting it. Records that resolve to the same path are appended together, in order, in one call.
Create directories `createDirs`	`boolean`	`true`	Create missing parent directories automatically.
Encoding `encoding`	`select`	`"utf8"`	Text encoding used when writing. `base64utf8`

Related nodes

The rest of the Storage 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.