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Stable API

On this page

  • What is the Stable API, and Should You Use It?
  • Backward Compatibility Guarantee
  • Declare the API Version
  • Checking Client API Versions
  • Create a Strict Client
  • Migrate To Stable API Commands
  • How To Use Commands and Features Outside of the Stable API
  • API V1 Commands
  • Parameters
  • Behavior

The MongoDB Stable API (previously labeled the Versioned API) lets you upgrade your MongoDB server at will, and ensure that behavior changes between MongoDB versions do not break your application.

MongoDB 5.0 introduces the Stable API for applications communicating with MongoDB server products. The Stable API allows you to specify which version of the MongoDB API your application runs against.

The Stable API provides long-term API stability for applications and supports more frequent releases and automatic server upgrades. This allows your applications to take advantage of rapidly released features without risking backwards-breaking changes.

The default behavior for your driver connection will continue to function as expected, even if you do not explicitly specify an apiVersion.

The Stable API encompasses the subset of MongoDB commands that applications use to read and write data, create collections and indexes, and perform other common tasks.


Starting in February 2022, the "Versioned API" terminology was changed to "Stable API". All concepts and features remain the same with this naming change.

Your application will not experience significant behavior changes resulting from server upgrades. This guarantee holds as long as the new server supports your specified API version.

To guarantee backward compatibility, your application must:

  • Declare an API version

  • Only use commands and features supported in your specified API version

  • Deploy with a supported version of an official driver

Use the Select your language drop-down menu in the upper-right to set the language of the examples on this page.

To use the Stable API, upgrade to the latest driver and create your application's MongoClient:

"1" is currently the only API version available.

By default, clients are non-strict. A non-strict client allows you to run any command, regardless of whether or not it belongs to the Stable API.

Use the serverStatus command to check for your application's configured API version. For each application connected to your MongoDB instance, an appname appears in the apiVersions document.

See metrics.apiVersions for more information.

db.runCommand( { serverStatus: 1 } ).metrics.apiVersions

A strict client rejects all commands outside of the Stable API. Attempts to use commands outside of the Stable API will receive the APIVersionError response.

Use the sample code to create a strict client:

To migrate your application to use the Stable API, you must:

  1. Run your application's test suite with the new MongoClient options.

  2. Determine which commands and features you're using that are outside of the Stable API.

  3. Migrate to alternative commands and features in the Stable API.

Once your application uses only commands and features defined in the Stable API, you can redeploy it with the new MongoClient options and be confident that future server upgrades won't negatively impact your application.

This example shows how to migrate an application that implements the count command to an alternative method of counting documents. Since the count command does not belong to the Stable API, this application cannot use the Stable API until the count command is removed from the code.

Use the sample code to create a sales collection in mongosh:

{ "_id" : 1, "item" : "abc", "price" : 10, "quantity" : 2, "date" : ISODate("2021-01-01T08:00:00Z") },
{ "_id" : 2, "item" : "jkl", "price" : 20, "quantity" : 1, "date" : ISODate("2021-02-03T09:00:00Z") },
{ "_id" : 3, "item" : "xyz", "price" : 5, "quantity" : 5, "date" : ISODate("2021-02-03T09:05:00Z") },
{ "_id" : 4, "item" : "abc", "price" : 10, "quantity" : 10, "date" : ISODate("2021-02-15T08:00:00Z") },
{ "_id" : 5, "item" : "xyz", "price" : 5, "quantity" : 10, "date" : ISODate("2021-02-15T09:05:00Z") },
{ "_id" : 6, "item" : "xyz", "price" : 5, "quantity" : 5, "date" : ISODate("2021-02-15T12:05:10Z") },
{ "_id" : 7, "item" : "xyz", "price" : 5, "quantity" : 10, "date" : ISODate("2021-02-15T14:12:12Z") },
{ "_id" : 8, "item" : "abc", "price" : 10, "quantity" : 5, "date" : ISODate("2021-03-16T20:20:13Z") }

For example, issuing db.sales.count() results in this error:

"ok" : 0,
"errmsg" : "Provided apiStrict:true, but the command count is not in API Version 1",
"code" : 323,
"codeName" : "APIStrictError"

However, the aggregate command is in the Stable API and can be used to obtain a count. Use the sample code to obtain a count from the sales collection in mongosh:

$group: {
_id: null,
count: { $count: { } }

This results in a document where the count field contains the number of documents in the collection:

{ "_id" : null, "count" : 8 }

To use commands and features outside of the Stable API, you can connect to your deployment with a non-strict client. By default, clients are non-strict.

Use the sample code to create a non-strict client:

Using this non-strict client allows you to run commands outside of the Stable API. For example, this non-strict client now allows you to use the count command once again.


Commands and features outside of the Stable API do not have the same backward compatibility guarantees as versioned alternatives.

API V1 protects you from API-breaking changes for the following commands:

[1](1, 2, 3, 4) API V1 may not support all available options for these commands. Refer to the specific command documentation for limitations specific to API V1.
[2] MongoDB does not guarantee that the output of the explain command will conform to the same format in future API versions.

You can specify the following optional parameters for Stable API in your application's MongoDB driver connection code. Check the MongoDB driver documentation for the driver you use in your application for more information:


API Version. "1" is currently the only supported API Version.

See APIVersionError.


If true, your application can only use commands defined for your specified apiVersion.

If not specified, defaults to false.

See APIStrictError.


If true, your application errors if it invokes a command or behavior that is deprecated in the specified apiVersion.

If not specified, defaults to false.

See APIDeprecationError.

Starting in MongoDB 5.0, API V1 database commands raise an error if passed a parameter not explicitly accepted by the command.

In MongoDB 4.4 and earlier, unrecognized parameters are silently ignored.

This table shows error responses for problematic Stable API requests.

Server Response

Specifies { apiDeprecationErrors: true } with API version V and uses a behavior deprecated in V.

Specifies { apiStrict: true } with API version V, but uses a behavior not in version V.

Specifies an apiVersion that the server does not support.

Specifies { apiStrict: true } or { apiDeprecationErrors: true } but omits apiVersion.

←  Server SessionsMigrate to a Later API Version →