The findAndModify command modifies and returns a single document. By default, the returned document does not include the modifications made on the update. To return the document with the modifications made on the update, use the new option.

The command has the following syntax:

  findAndModify: <collection-name>,
  query: <document>,
  sort: <document>,
  remove: <boolean>,
  update: <document>,
  new: <boolean>,
  fields: <document>,
  upsert: <boolean>,
  bypassDocumentValidation: <boolean>,
  writeConcern: <document>,
  collation: <document>,
  arrayFilters: <array>

The findAndModify command takes the following fields:

Field Type Description
query document

Optional. The selection criteria for the modification. The query field employs the same query selectors as used in the db.collection.find() method. Although the query may match multiple documents, findAndModify will only select one document to modify.

If unspecified, defaults to an empty document.

Starting in MongoDB 3.6.14+ (and 3.4.23+), the operation errors if the query argument is not a document.

sort document

Optional. Determines which document the operation modifies if the query selects multiple documents. findAndModify modifies the first document in the sort order specified by this argument.

Starting in MongoDB 3.6.14+ (and 3.4.23+), the operation errors if the sort argument is not a document.

remove boolean Must specify either the remove or the update field. Removes the document specified in the query field. Set this to true to remove the selected document . The default is false.
update document Must specify either the remove or the update field. Performs an update of the selected document. The update field employs the same update operators or field: value specifications to modify the selected document.
new boolean Optional. When true, returns the modified document rather than the original. The findAndModify method ignores the new option for remove operations. The default is false.
fields document

Optional. A subset of fields to return. The fields document specifies an inclusion of a field with 1, as in: fields: { <field1>: 1, <field2>: 1, ... }. See projection.

Starting in MongoDB 3.6.14+ (and 3.4.23+), the operation errors if the fields argument is not a document.

upsert boolean

Optional. Used in conjuction with the update field.

When true, findAndModify() either:

  • Creates a new document if no documents match the query. For more details see upsert behavior.
  • Updates a single document that matches the query.

To avoid multiple upserts, ensure that the query fields are uniquely indexed.

Defaults to false.

bypassDocumentValidation boolean

Optional. Enables findAndModify to bypass document validation during the operation. This lets you update documents that do not meet the validation requirements.

New in version 3.2.

writeConcern document

Optional. A document expressing the write concern. Omit to use the default write concern.

New in version 3.2.

maxTimeMS integer Optional. Specifies a time limit in milliseconds for processing the operation.
findAndModify string The collection against which to run the command.
collation document


Specifies the collation to use for the operation.

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

The collation option has the following syntax:

collation: {
   locale: <string>,
   caseLevel: <boolean>,
   caseFirst: <string>,
   strength: <int>,
   numericOrdering: <boolean>,
   alternate: <string>,
   maxVariable: <string>,
   backwards: <boolean>

When specifying collation, the locale field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document.

If the collation is unspecified but the collection has a default collation (see db.createCollection()), the operation uses the collation specified for the collection.

If no collation is specified for the collection or for the operations, MongoDB uses the simple binary comparison used in prior versions for string comparisons.

You cannot specify multiple collations for an operation. For example, you cannot specify different collations per field, or if performing a find with a sort, you cannot use one collation for the find and another for the sort.

New in version 3.4.

arrayFilters array

Optional. An array of filter documents that determines which array elements to modify for an update operation on an array field.

In the update document, use the $[<identifier>] filtered positional operator to define an identifier, which you then reference in the array filter documents. You cannot have an array filter document for an identifier if the identifier is not included in the update document.


The <identifier> must begin with a lowercase letter and contain only alphanumeric characters.

You can include the same identifier multiple times in the update document; however, for each distinct identifier ($[identifier]) in the update document, you must specify exactly one corresponding array filter document. That is, you cannot specify multiple array filter documents for the same identifier. For example, if the update statement includes the identifier x (possibly multiple times), you cannot specify the following for arrayFilters that includes 2 separate filter documents for x:

  { "x.a": { $gt: 85 } },
  { "x.b": { $gt: 80 } }

However, you can specify compound conditions on the same identifier in a single filter document, such as in the following examples:

  { $or: [{"x.a": {$gt: 85}}, {"x.b": {$gt: 80}}] }

  { $and: [{"x.a": {$gt: 85}}, {"x.b": {$gt: 80}}] }

  { "x.a": { $gt: 85 }, "x.b": { $gt: 80 } }

For examples, see Specify arrayFilters for an Array Update Operations.

New in version 3.6.


The findAndModify command returns a document with the following fields:

Field Type Description
value document Contains the command’s returned value. See value for details.
lastErrorObject document Contains information about updated documents. See lastErrorObject for details.
ok number Contains the command’s execution status. 1 on success, or 0 if an error occurred.


The lastErrorObject embedded document contains the following fields:

Field Type Description
updatedExisting boolean Contains true if an update operation modified an existing document.
upserted document Contains the ObjectId of the inserted document if an update operation with upsert: true resulted in a new document.


For remove operations, value contains the removed document if the query matches a document. If the query does not match a document to remove, value contains null.

For update operations, the value embedded document contains the following:

  • If the new parameter is not set or is false:
    • the pre-modification document if the query matches a document;
    • otherwise, null.
  • If new is true:
    • the modified document if the query returns a match;
    • the inserted document if upsert: true and no document matches the query;
    • otherwise, null.

Changed in version 3.0: In previous versions, if for the update, sort is specified, and upsert: true, and the new option is not set or new: false, findAndModify returns an empty document {} in the value field instead of null.


Upsert and Unique Index

When the findAndModify command includes the upsert: true option and the query field(s) is not uniquely indexed, the command could insert a document multiple times in certain circumstances.

Consider an example where no document with the name Andy exists and multiple clients issue the following command:

     findAndModify: "people",
     query: { name: "Andy" },
     sort: { rating: 1 },
     update: { $inc: { score: 1 } },
     upsert: true

If all the commands finish the query phase before any command starts the modify phase, and there is no unique index on the name field, the commands may each perform an upsert, creating multiple duplicate documents.

To prevent the creation of multiple duplicate documents, create a unique index on the name field. With the unique index in place, then the multiple findAndModify commands will exhibit one of the following behaviors:

  • Exactly one findAndModify successfully inserts a new document.
  • Zero or more findAndModify commands update the newly inserted document.
  • Zero or more findAndModify commands fail when they attempt to insert a duplicate. If the command fails due to a unique index constraint violation, you can retry the command. Absent a delete of the document, the retry should not fail.

Sharded Collections