> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://mailchimp.com/developer/marketing/api/campaigns/upsert-content/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://mailchimp.com/_mcp/server.

# Set campaign content

PUT https://api.mailchimp.com/3.0/campaigns/{campaign_id}/content
Content-Type: application/json

Set the content for a campaign.

Reference: https://mailchimp.com/developer/marketing/api/campaigns/upsert-content

## Authentication

- `Authorization` header (bearer token, required) — Authorization using a Mailchimp API key (a.k.a. Bearer token)
- `Authorization` header (bearer token, required) — Authorization using OAuth

## Request

### Path parameters

- `campaign_id` (string, required) — The unique id for the campaign.

### Body (application/json)

This endpoint expects a CampaignContent.

- `_links` (list of CampaignContentLinksItems, optional) — A list of link types and descriptions for the API schema documents.
- `archive_html` (string, optional) — The Archive HTML for the campaign.
- `html` (string, optional) — The raw HTML for the campaign.
- `plain_text` (string, optional) — The plain-text portion of the campaign. If left unspecified, we'll generate this automatically.
- `variate_contents` (list of CampaignContentVariateContentsItems, optional) — Content options for multivariate campaigns.

## Response

### 200

- `_links` (list of CampaignContentLinksItems, optional) — A list of link types and descriptions for the API schema documents.
- `archive_html` (string, optional) — The Archive HTML for the campaign.
- `html` (string, optional) — The raw HTML for the campaign.
- `plain_text` (string, optional) — The plain-text portion of the campaign. If left unspecified, we'll generate this automatically.
- `variate_contents` (list of CampaignContentVariateContentsItems, optional) — Content options for multivariate campaigns.

## Types

### CampaignContentLinksItems

This object represents a link from the resource where it is found to another resource or action that may be performed.

- `href` (string, optional) — This property contains a fully-qualified URL that can be called to retrieve the linked resource or perform the linked action.
- `method` (enum, optional) — The HTTP method that should be used when accessing the URL defined in 'href'.
  - Allowed values: `GET`, `POST`, `PUT`, `PATCH`, `DELETE`, `OPTIONS`, `HEAD`
- `rel` (string, optional) — As with an HTML 'rel' attribute, this describes the type of link.
- `schema` (string, optional) — For HTTP methods that can receive bodies (POST and PUT), this is a URL representing the schema that the body should conform to.
- `targetSchema` (string, optional) — For GETs, this is a URL representing the schema that the response should conform to.

### CampaignContentVariateContentsItems

- `content_label` (string, optional) — Label used to identify the content option.
- `html` (string, optional) — The raw HTML for the campaign.
- `plain_text` (string, optional) — The plain-text portion of the campaign. If left unspecified, we'll generate this automatically.

## Examples

**Request**

```json
{}
```

**Response**

```json
{
  "_links": [
    {
      "href": "string",
      "method": "GET",
      "rel": "string",
      "schema": "string",
      "targetSchema": "string"
    }
  ],
  "archive_html": "<!DOCTYPE html><html xmlns=http://www.w3.org/1999/xhtml><head><meta http-equiv=Content-Type content=\"text/html; charset=UTF-8\"><title>My Subject</title><style type=text/css>body{background-color:#d0e4fe}</style><body leftmargin=0 marginwidth=0 topmargin=0 marginheight=0 offset=0>",
  "html": "string",
  "plain_text": "string",
  "variate_contents": [
    {
      "content_label": "Green header",
      "html": "<!DOCTYPE html><html xmlns=http://www.w3.org/1999/xhtml><head><meta http-equiv=Content-Type content=\"text/html; charset=UTF-8\"><title>*|MC:SUBJECT|*</title><style type=text/css>body{background-color:#d0e4fe}</style><body leftmargin=0 marginwidth=0 topmargin=0 marginheight=0 offset=0>",
      "plain_text": "string"
    }
  ]
}
```

**SDK Code**

```python
import requests

url = "https://api.mailchimp.com/3.0/campaigns/campaign_id/content"

payload = {}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.put(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.mailchimp.com/3.0/campaigns/campaign_id/content';
const options = {
  method: 'PUT',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.mailchimp.com/3.0/campaigns/campaign_id/content"

	payload := strings.NewReader("{}")

	req, _ := http.NewRequest("PUT", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.mailchimp.com/3.0/campaigns/campaign_id/content")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Put.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{}"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.put("https://api.mailchimp.com/3.0/campaigns/campaign_id/content")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{}")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('PUT', 'https://api.mailchimp.com/3.0/campaigns/campaign_id/content', [
  'body' => '{}',
  'headers' => [
    'Authorization' => 'Bearer <token>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://api.mailchimp.com/3.0/campaigns/campaign_id/content");
var request = new RestRequest(Method.PUT);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.mailchimp.com/3.0/campaigns/campaign_id/content")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "PUT"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```

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