This page documents the write methods of the Zotero Web API. See the Basics page for basic information on accessing the API, including possible HTTP status codes not listed here.

An API key with write access to a given library is necessary to use write methods.

By default, objects returned from the API in format=json mode include a data property containing “editable JSON” — that is, all the object fields that can be modified and sent back to the server:

{
  "key": "ABCD2345",
  "version": 1,
  "library": { ... },
  "links": { ... },
  "meta": { ... },
  "data": {
    "key": "ABCD2345",
    "version": 1,
    "itemType": "webpage",
    "title": "Zotero Quick Start Guide",
    "creators": [
        {
            "creatorType": "author",
            "name": "Center for History and New Media"
        }
    ],
    "abstractNote": "",
    "websiteTitle": "Zotero",
    "websiteType": "",
    "date": "",
    "shortTitle": "",
    "url": "https://www.zotero.org/support/quick_start_guide",
    "accessDate": "2014-06-12T21:28:55Z",
    "language": "",
    "rights": "",
    "extra": "",
    "dateAdded": "2014-06-12T21:28:55Z",
    "dateModified": "2014-06-12T21:28:55Z",
    "tags": [],
    "collections": [],
    "relations": {}
  }
}

There are two ways to make changes to the provided JSON:

For programmatic access to the API, the recommended approach is to extract the editable JSON from the data property, make changes as necesssary, and upload just the editable JSON back to the API. For new items, an empty template of the editable JSON can be retrieved from the API.

This approach reduces upload bandwidth by sending only the data that is actually processed by the server. (For an even more efficient upload, the HTTP PATCH method, discussed below, can be used to send only the fields that have changed.) The examples in this documentation assume programmatic access.

For more casual access, the API supports standard REST behavior, allowing the entire downloaded JSON to be reuploaded. This allows edits to be performed without writing a single line of code:

$ URL="https://api.zotero.org/users/1234567/items"
$ API_KEY="P9NiFoyLeZu2bZNvvuQPDWsd"
$ curl -H "Zotero-API-Key: $API_KEY" $URL > items.json
$ vi items.json  # edit the item data
$ curl -H "Zotero-API-Key: $API_KEY" -d @items.json -v $URL

In this example, a JSON array of items is being saved to a text file, modified in a text editor, and then POSTed back to the same URL.

This approach allows a complicated task such as batch editing to be performed using only cURL and a text editor. Any objects modified in the text file will be updated on the server, while unmodified objects will be left unchanged.

A similar process can be used with PUT for individual objects:

$ URL="https://api.zotero.org/users/1234567/items/ABCD2345"
$ API_KEY="P9NiFoyLeZu2bZNvvuQPDWsd"
$ curl -H "Zotero-API-Key: $API_KEY" $URL > item.json
$ vi items.json  # edit the item data
$ curl -H "Zotero-API-Key: $API_KEY" -X PUT -d @item.json -v $URL

Note that when uploading full JSON, only the data property is processed. All other properties (library, links, meta, etc.) are ignored.

When creating a new item, first get empty JSON for the item type with an item template request (or use a cached version of the template). Then modify it and resubmit it to the server in an array:

POST <userOrGroupPrefix>/items
Content-Type: application/json
Zotero-Write-Token: <write token> or If-Unmodified-Since-Version: <last library version>

[
  {
    "itemType" : "book",
    "title" : "My Book",
    "creators" : [
      {
        "creatorType":"author",
        "firstName" : "Sam",
        "lastName" : "McAuthor"
      },
      {
        "creatorType":"editor",
        "name" : "John T. Singlefield"
      }
    ],
    "tags" : [
      { "tag" : "awesome" },
      { "tag" : "rad", "type" : 1 }
    ],
    "collections" : [
      "BCDE3456", "CDEF4567"
    ],
    "relations" : {
      "owl:sameAs" : "http://zotero.org/groups/1/items/JKLM6543",
      "dc:relation" : "http://zotero.org/groups/1/items/PQRS6789",
      "dc:replaces" : "http://zotero.org/users/1/items/BCDE5432"
    }
  }
]

All properties other than itemType, tags, collections, and relations are optional.

200 OK response:

{
  "success": {
    "0": "<itemKey>"
  },
  "unchanged": {},
  "failed": {},
  }
}

See Creating Multiple Objects for more information on the response format.

See Creating Multiple Objects.

To update an existing item, first retrieve the current version of the item:

GET <userOrGroupPrefix>/items/<itemKey>

The editable data, similar to the item data shown above in Creating an Item, will be found in the data property in the response.

The API supports two ways of modifying item data: by uploading full item data (PUT) or by sending just the data that changed (PATCH).

With PUT, you submit the item's complete editable JSON to the server, typically by modifying the downloaded editable JSON — that is, the contents of the data property — directly and resubmitting it:

PUT <userOrGroupPrefix>/items/<itemKey>
Content-Type: application/json

{
  "key": "ABCD2345",
  "version": 1,
  "itemType" : "book",
  "title" : "My Amazing Book",
  "creators" : [
    {
      "creatorType":"author",
      "firstName" : "Sam",
      "lastName" : "McAuthor"
    },
    {
      "creatorType":"editor",
      "name" : "Jenny L. Singlefield"
    }
  ],
  "tags" : [
    { "tag" : "awesome" },
    { "tag" : "rad", "type" : 1 }
  ],
  "collections" : [
    "BCDE3456", "CDEF4567"
  ],
  "relations" : {
    "owl:sameAs" : "http://zotero.org/groups/1/items/JKLM6543",
    "dc:relation" : "http://zotero.org/groups/1/items/PQRS6789",
    "dc:replaces" : "http://zotero.org/users/1/items/BCDE5432"
  }
}

All properties other than itemType, tags, collections, and relations are optional. Any existing fields not specified will be removed from the item. If creators, tags, collections, or relations are empty, any associated creators/tags/collections/relations will be removed from the item.

With PATCH, you can submit just the properties that have actually changed, for a potentially much more efficient operation. Properties not included in the uploaded JSON are left untouched on the server. To clear a property, pass an empty string or an empty array as appropriate.

PATCH <userOrGroupPrefix>/items/<itemKey>
If-Unmodified-Since-Version: <last item version>

{
  "date" : "2013"
  "collections" : [
    "BCDE3456", "CDEF4567"
  ]
}

This would add a date field to the item and add it in the two specified collections if not already present. Array properties are interpreted as complete lists, so omitting a collection key would cause the item to be removed from that collection.

The PATCH behavior is also available when modifying multiple items via POST.

Notes and attachments can be made child items by assigning the parent item's key to the parentItem property. If parent and child items are created in the same POST request, the child items must appear after the parent item in the array of items, with a locally created item key.

The item's current version number is included in the version JSON property, as well as in the Last-Modified-Version header of single-item requests. PUT and PATCH requests must include the item's current version number in either the version property or the If-Unmodified-Since-Version header. (version is included in responses from the API, so clients that simply modify the editable data do not need to bother with a version header.) If the item has been changed on the server since the item was retrieved, the write request will be rejected with a 412 Precondition Failed error, and the most recent version of the item will have to be retrieved from the server before changes can be made. See Version Numbers for more on library and object versioning.

See Updating Multiple Objects.

DELETE <userOrGroupPrefix>/items/<itemKey>
If-Unmodified-Since-Version: <last item version>

Up to 50 items can be deleted in a single request.

DELETE <userOrGroupPrefix>/items?itemKey=<key>,<key>,<key>
If-Unmodified-Since-Version: <last library version>

204 No Content
Last-Modified-Version: <library version>

POST <userOrGroupPrefix>/collections
Content-Type: application/json
Zotero-Write-Token: <write token> or If-Unmodified-Since-Version: <last library version>

[
  {
    "name" : "My Collection",
    "parentCollection" : "QRST9876"
  }
]

GET <userOrGroupPrefix>/collections/<collectionKey>

Editable JSON will be found in the data property.

PUT <userOrGroupPrefix>/collections/<collectionKey>
Content-Type: application/json

{
  "key" : "DM2F65CA",
  "version" : 156,
  "name" : "My Collection",
  "parentCollection" : false
}

Items can be added to or removed from collections via the collections property in the item JSON.

DELETE <userOrGroupPrefix>/collections/<collectionKey>
If-Unmodified-Since-Version: <last collection version>

Up to 50 collections can be deleted in a single request.

DELETE <userOrGroupPrefix>/collections?collectionKey=<collectionKey>,<collectionKey>,<collectionKey>
If-Unmodified-Since-Version: <last library version>

204 No Content
Last-Modified-Version: <library version>

POST <userOrGroupPrefix>/searches
Content-Type: application/json
Zotero-Write-Token: <write token> or If-Unmodified-Since-Version: <last library version>

[
  {
    "name": "My Search",
    "conditions": [
      {
        "condition": "title",
        "operator": "contains",
        "value": "foo"
      },
      {
        "condition": "date",
        "operator": "isInTheLast",
        "value": "7 days"
      }
    ]
  }
]

Up to 50 searches can be deleted in a single request.

DELETE <userOrGroupPrefix>/searches?searchKey=<searchKey>,<searchKey>,<searchKey>
If-Unmodified-Since-Version: <last library version>

204 No Content
Last-Modified-Version: <library version>

Up to 50 tags can be deleted in a single request.

DELETE <userOrGroupPrefix>/tags?tag=<URL-encoded tag 1> || <URL-encoded tag 2> || <URL-encoded tag 3>
If-Unmodified-Since-Version: <last library version>

204 No Content
Last-Modified-Version: <library version>

Up to 50 collections, saved searches, or items can be created in a single request by including multiple objects in an array:

POST <userOrGroupPrefix>/collections
Content-Type: application/json
Zotero-Write-Token: <write token> or If-Unmodified-Since-Version: <last library version>

[
  {
    "name" : "My Collection",
    "parentCollection": "QRST9876"
  },
  {
    "name": "My Other Collection"
  }
]

For syncing objects with predetermined keys, an object key can also be provided with new objects.

200 response:

Content-Type: application/json
Last-Modified-Version: <library version>

{
  "successful": {
    "0": "<saved object>",
    "2": "<saved object>"
  },
  "unchanged": {
    "4": "<objectKey>"
  }
  "failed": {
    "1": {
      "key": "<objectKey>",
      "code": <HTTP response code>,
      "message": "<error message>"
    },
    "3": {
      "key": "<objectKey>",
      "code": <HTTP response code>,
      "message": "<error message>"
    },
  }
}

The keys of the successful, unchanged, and failed objects are the numeric indexes of the Zotero objects in the uploaded array. The Last-Modified-Version is the version that has been assigned to any Zotero objects in the successful object — that is, objects that were modified in this request.

Up to 50 collections, saved searches, or items can be updated in a single request.

Follow the instructions in Creating Multiple Objects, but include a key and version property in each object. If modifying editable JSON returned from the API, these properties will already exist and shouldn't be modified. As an alternative to individual version properties, the last-known library version can be passed via the If-Unmodified-Since-Version HTTP Header.

Items can also include dateAdded and dateModified properties containing timestamps in ISO 8601 format (e.g., “2014-06-10T13:52:43Z”). If dateAdded is included with an existing item, it must match the existing dateAdded value or else the API will return a 400 error. If a new dateModified time is not included with an update to existing item, the item's dateModified value will be set to the current time. Editable JSON returned from the API includes dateAdded and dateModified in the correct format, so clients that are content with server-set modification times can simply ignore these properties.

POST <userOrGroupPrefix>/collections
Content-Type: application/json

[
  {
    "key": "BD85JEM4",
    "version": 414,
    "name": "My Collection",
    "parentCollection": false
  },
  {
    "key": "MNC5SAPD",
    "version": 416
    "name": "My Subcollection",
    "parentCollection": "BD85JEM4"
  }
]

The response is the same as that in Creating Multiple Objects.

Note that POST follows PATCH semantics, meaning that any properties not specified will be left untouched on the server. To erase an existing property, include it with an empty string or false as the value.

While the server will automatically generate valid keys for uploaded objects, in some situations, such as when syncing or creating a parent and child item in the same request, it may be desirable or necessary to create object keys locally.

Local object keys should conform to the pattern /[23456789ABCDEFGHIJKLMNPQRSTUVWXYZ]{8}/.

Zotero-Write-Token: 19a4f01ad623aa7214f82347e3711f56

Zotero-Write-Token is an optional HTTP header, containing a client-generated random 32-character identifier string, that can be included with unversioned write requests to prevent them from being processed more than once (e.g., if a user clicks a form submit button twice). The Zotero server caches write tokens for successful requests for 12 hours, and subsequent requests from the same API key using the same write token will be rejected with a 412 Precondition Failed status code. If a request fails, the write token will not be stored.

If using versioned write requests (i.e., those that include an If-Unmodified-Since-Version HTTP header or individual object version properties), Zotero-Write-Token is redundant and should be omitted.

See the Syncing page for an example workflow that puts together read and write methods for complete and efficient syncing of Zotero data via the API.