How can I set up nested JSON parameters and arrays in the n8n HTTP Request node?

Below is an explanation along with some examples of how to set up your JSON parameters correctly in the HTTP Request node when you need nested objects and arrays.

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JSON Format for Nested Objects

If you want to send a nested JSON object, you need to ensure that your JSON is valid. For example, if you need to send something like a person’s email information, your JSON should look like this:

JSONCopied
{
  "person": {
    "email": "user@example.com"
  }
}

Make sure you’re not including extra JSON schema definitions (like the “type” or “description” keys) if the API expects the actual values. When you provide the JSON in the HTTP Request node’s parameters, you want to send the data exactly as required by your endpoint.

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Using Arrays (e.g. Array of Emails)

If you need to provide an array of emails, format it with square brackets. Here’s an example:

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{
  "emails": [
    "first@example.com",
    "second@example.com",
    "third@example.com"
  ]
}

This sends the key emails with an array of strings.

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Tips for Using the HTTP Request Node with JSON

1. Select the JSON Option: When working in the HTTP Request node, if you choose the JSON option for query parameters or body, the node will expect a valid JSON format. Avoid additional schema information unless the endpoint explicitly needs it.

2. Use Expressions When Needed: If some of the values need to be computed or come from previous nodes, click the gear icon and use an expression. For example:

   JSONCopied
   {
     "person": {
       "email": "={{$json[\"email\"]}}"
     }
   }

3. Check the Content-Type Header: If you are POSTing JSON data, ensure that your headers include Content-Type: application/json (this is usually handled automatically by the node when you use the JSON option).

4. Avoid Misplaced Placeholders: The error regarding a "wrongly set up placeholder" often means that either the placeholder isn’t correctly wrapped in an expression (using the ={{ ... }} syntax) or the JSON structure is not valid. Double-check that any dynamic parts of your JSON follow the expression syntax exactly.

5. Validation with a Formatter or Code Node: If needed, use a Code node (or other transformation nodes like AI Transform) to build the JSON object and then pass it as a string into your HTTP Request node.

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Example Use Case in Your Workflow

Assume you want to create a Google Calendar event using an HTTP request that expects a nested object with an organizer email and an array of guest emails. Your JSON could look like this:

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{
  "organizer": {
    "email": "organizer@example.com"
  },
  "guests": [
    "guest1@example.com",
    "guest2@example.com"
  ]
}

Place the above JSON into the appropriate field in the HTTP Request node (using the JSON option). If any of the values are dynamic, wrap them with the expression syntax.

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By following these guidelines, your nested objects and arrays should be set up correctly without placeholder errors. Let me know if you need any further clarification on integrating the JSON format into your HTTP Request node.