JSON

JSON

Parse, build, pick from and repair JSON.

What it does

Reads, writes and rescues JSON. It offers five operations: parse a string into real data, stringify data back into a string, pick a value out by dot path, deep-merge two objects, and repair malformed JSON while reporting what it had to fix.

When to use it

Use this node to turn JSON-LD scraped off a page into fields the next node can address, to rescue model output that is nearly valid without wrapping a Code node in a try/catch, or to hand a clean object to a downstream parser.

Inputs and settings

Setting	Notes
Operation	What to do with the JSON: Parse, Stringify, Pick by path, Merge or Repair. Defaults to Parse.
JSON	The JSON text or data to work on. Accepts an expression such as {{ $json.raw }}.
Source Field	Field on the incoming item to read when the JSON field above is left empty, for example body.
Path	Dot path read by Pick by path, for example product.offers.price.
Merge With	The object Merge folds into the JSON. Its values win on conflict.
Repair If Needed	For Parse: try to fix nearly-valid JSON before parsing it. Fixes code fences, surrounding prose, comments, single quotes, unquoted keys, trailing commas and cut-off tails. Valid JSON is never touched. Defaults to on.
Pretty Print	For Stringify: indent the output. Defaults to off.
Put Result In Field	Name of the field holding the answer. Defaults to data. For Parse and Merge, leaving the default lets the parsed object become the item itself when it is an object.

Outputs

• Parse turns text into data. A parsed object becomes the outgoing item itself, so its fields are addressable downstream without a wrapper; an array becomes one item per entry; anything else is placed in Put Result In Field. When repair was needed, the steps applied are attached as a _repaired field.
• Stringify returns the JSON text in Put Result In Field, indented when Pretty Print is on.
• Pick by path returns the value at Path, or fails if the path does not exist.
• Merge deep-merges Merge With into the source (plain objects merge key by key; arrays and non-objects replace wholesale).
• Repair returns the repaired text, a repaired flag, the list of steps applied, and a valid flag saying whether the result now parses.

How repair works

Repair applies up to seven passes in order — strip a markdown code fence, trim surrounding prose, remove // and /* */ comments, convert single quotes to double, quote unquoted keys, drop trailing commas, and close a truncated tail. It short-circuits the moment the text parses: valid JSON is returned byte-identical with no passes applied, and each pass is kept only if the text still has a chance of parsing.

Repair never guesses values. A truncated payload is closed — open brackets are shut and a half-written string is ended — but a key whose value never arrived is dropped, not filled with null, because downstream could not tell an invented null from a real one. Non-JSON prose with no bracketed payload stays unparseable rather than being coerced. Strings are respected throughout: a brace, comma or comment marker inside a quoted string is treated as data, not syntax.

Dependencies and credentials

• No credential or node dependency is required. The node runs entirely in the browser.

Example workflow

Place JSON after a node that returns model output, set Operation to Parse and leave Repair If Needed on. A response wrapped in a ```json code fence with a trailing comma parses cleanly, and a _repaired field records which fixes were needed. Follow with Pick by path set to product.offers.price to read a single value out.

Troubleshooting

• With Repair If Needed off, invalid JSON fails and the message suggests turning repair on.
• If Parse still fails after repair, the input is not nearly-valid JSON — repair only undoes the small, fixed set of malformations above and refuses to invent data.
• Pick by path fails when the path does not exist. Check the dot path against the actual structure.
• Merge fails if Merge With is empty. Stringify fails on a circular reference or a value with no JSON form.
• Repair reports rather than throws: check the valid flag to tell rescued JSON from JSON that is still broken.

Related nodes

• Pick Field
• Edit Fields
• Code
• Node types overview