v6.20.0

6.20.0 (2025-09-17)

The MongoDB Node.js team is pleased to announce version 6.20.0 of the mongodb package!

Release Notes

Collection and Db objects now provide references to their Db and MongoClient

import { MongoClient } from 'mongodb';

const client = new MongoClient(process.env.MONGODB_URI);
const db = client.db('test');
assert(db.client === client); // returns the MongoClient associated with the Db object
const collection = db.collection('test');
assert(collection.db === db); // returns the Db associated with the Collection object

Hint is supported with unacknowledged writes for delete, update and findAndModify commands on servers that support hint

The driver no longer throws errors when hint is provided to unacknowledged writes for delete, update and findAndModify commands in the following circumstances:

• No error is thrown for update commands.
• No errors are thrown for delete and findAndModify commands on servers >=4.4.

ServerCapabilities and ReadPreference.minWireVersion are deprecated

Neither the ServerCapabilities class nor the ReadPreference.minWireVersion property were ever intended for public use and, internally, are effectively dead code with the driver's minimum supported server version being 4.2.

Driver info and metadata MongoClient options have been deprecated.

These will be made internal in a future major release:

• driverInfo
• additionalDriverInfo
• metadata
• extendedMetadata

CommandOperationOptions.retryWrites is deprecated

CommandOperationOptions.retryWrites is deprecated. This per‑command option has no effect; the Node.js driver only honors retryWrites when configured at the client level (MongoClient options) or via the connection string. Do not use this option on individual commands. There is no runtime behavior change because it was already ignored, but it will be removed in an upcoming major release and may cause type or build errors in code that references it. To control retryable writes, set retryWrites in MongoClient options or include retryWrites=true|false in the connection string.

ChangeStream .tryNext() now updates resumeToken to prevent duplicates after resume

When .tryNext() returns a change document, the driver now caches its resumeToken, aligning its behavior with .next() and the 'change' event. If .tryNext() returns null (no new changes), nothing is cached, which is unchanged from previous behavior.

Previously, .tryNext() did not update the resumeToken, so a resumable error could cause a resume from an older token and re-deliver already processed changes. With this release, resumes continue from the latest token observed via .tryNext(), preventing duplicates.

const changeStream = collection.watch([]);
while (true) {
  const change = await changeStream.tryNext(); // prior versions could return duplicates
  await scheduler.wait(1000);  // delay since tryNext() does not wait for changes
}

Applications that poll change streams with .tryNext() in non-blocking loops benefit directly. There are no API changes; if you previously tracked and passed resumeAfter or startAfter manually, you can now rely on the driver’s built-in token caching.

Huge thanks to @rkistner for bringing this bug to our attention and for sharing code to reproduce it. Huge thanks as well to @Omnicpie for investigating and implementing a fix.

Change Streams now resume on MongoServerSelectionError

When the driver encounters a MongoServerSelectionError while processing a Change Stream (e.g., due to a transient network issue or during an election), it now treats the error as resumable and attempts to resume using the latest cached resume token.

This applies to both iterator and event-emitter usage:

// Iterator form
const changeStream = collection.watch([]);
for await (const change of changeStream) {
  // process change
}

// Event-emitter form
const changeStream = collection.watch([]);
changeStream.on('change', (change) => {
  // process change
});

There are no API changes. If you previously caught MongoServerSelectionError and implemented manual resume logic, you can now rely on the driver’s built-in resume mechanism, which uses the cached resume token from the change event’s _id to continue without losing events.

Huge thanks to @grossbart for bringing this bug to our attention, investigating it and for sharing code to reproduce it!

MongoClient.appendMetadata() ignores duplicate metadata

MongoClient.appendMetadata() will no longer append metadata if it duplicates the metadata already appended to the MongoClient.

Features

• NODE-7125: add db and client properties to collection and database objects (#4640) (3469f86)
• NODE-7134: allow hint with unacknowledged writes for delete, update and findAndModify commands (#4647) (82d6ce6)
• NODE-7139: remove pre-4.2 logic and deprecate dead code (#4657) (14303bc)
• NODE-7140: deprecate driver info options (#4654) (b813c85)
• NODE-7157: deprecate retryWrites in CommandOperationOptions (#4661) (620972d)

Bug Fixes

• NODE-4763: cache resumeToken in ChangeStream.tryNext() (#4636) (8331a93)
• NODE-6858: treat MongoServerSelectionError as a resumable error for Change Streams (#4653) (c6d64e7)
• NODE-7138: prevent duplicate metadata from being appended to handshake metadata (#4651) (05c230c)

Documentation

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• API
• Changelog

We invite you to try the mongodb library immediately, and report any issues to the NODE project.

v6.19.0

6.19.0 (2025-08-26)

The MongoDB Node.js team is pleased to announce version 6.19.0 of the mongodb package!

Release Notes

Experimental Support for Queryable Encryption Text Field Prefix, Suffix and Substring Queries

Important

Substring, prefix and suffix search are in preview and should be used for experimental workloads only. These features are unstable and their security is not guaranteed until released as Generally Available (GA). The GA version of these features may not be backwards compatible with the preview version.

When using Queryable Encryption with both automatic encryption and explicit encryption, text fields can now be queried using prefix, suffix and substring queries. This feature requires mongodb-client-encryption@>=6.5.0.

Allow a secureContext for Auto Encryption and Client Encryption TLS options

This can be provided in the tlsOptions option both both objects.

import * as tls from 'tls';
import { ClientEncryption, MongoClient } from 'mongodb';

const caFile = await fs.readFile(process.env.CSFLE_TLS_CA_FILE);
const certFile = await fs.readFile(process.env.CSFLE_TLS_CLIENT_CERT_FILE);
const secureContextOptions = {
  ca: caFile,
  key: certFile,
  cert: certFile
};
const options = {
  keyVaultNamespace: 'db.coll',
  kmsProviders: {
    aws: {}
    }
  },
  tlsOptions: {
    aws: {
      secureContext: tls.createSecureContext(secureContextOptions),
    }
  }
};

const client = this.configuration.newClient({}, { autoEncryption: { ...options, schemaMap } });
const clientEncryption = new ClientEncryption(client, options);

collection.findOne() and collection.find() will no longer potentially leave open cursors on the server

The findOne command will now always set the limit option to 1 and singleBatch to true. The limit, noCursorResponse and batchSize options have also been deprecated, and the command will guarantee no more cursors can be orphaned and no killCursors command will be potentially executed.

find will now set limit to batchSize + 1 when both options were equal, to avoid leaving cursors open.

Clients no longer send a ping on connect

When authentication is enabled, the MongoClient will no longer send a ping command when connecting since it is unnecessary. Instead it will check a connection out of the pool to force the initial handshake, and check it back in.

Features

• NODE-4179: allow secureContext in KMS TLS options (#4578) (0ea6eaa)
• NODE-6472: findOne and find no longer keep open cursors (#4580) (be7f808)
• NODE-7020: remove ping on connect (#4607) (3d296b7)
• NODE-7059, NODE-7008: add support for text queries for QE string fields (#4597) (e4492f3)

Documentation

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• Changelog

We invite you to try the mongodb library immediately, and report any issues to the NODE project.

v6.18.0

6.18.0 (2025-07-22)

The MongoDB Node.js team is pleased to announce version 6.18.0 of the mongodb package!

Release Notes

New appendMetadata API allows clients to add handshake metadata post construction

Driver information such as name, version, and platform are allowed:

import { MongoClient } from 'mongodb';

const client = new MongoClient(process.env.MONGODB_URI);
client.appendMetadata({ name: 'my library', version: '1.0', platform: 'NodeJS' });

Cursors lazily instantiate sessions

In previous versions, sessions were eagerly allocated whenever a cursor was created, regardless of whether or not a cursor was actually iterated (and the session was actually needed). Some driver APIs (FindCursor.count(), AggregationCursor.explain() and FindCursor.explain()) don't actually iterate the cursor they are executed on. This can lead to client sessions being created and never being cleaned up.

With this update, sessions are not allocated until the cursor is iterated.

Idle connections are now pruned during periods of no activity even when minPoolSize=0

A MongoClient configured with a maxIdleTimeMS and minPoolSize of 0 is advantageous for workloads that have sustained periods of little or no activity because it allows the connection pool to close connections that are unused during these periods of inactivity. However, due to a bug in the ConnectionPool implementation, idle / perished connections were not cleaned up unless minPoolSize was non-zero.

With the changes in this PR, the ConnectionPool now always cleans up idle connections, regardless of minPoolSize.

ChangeStream event interfaces include a wallTime property

This property is available on all types with the exception of reshard collection and refine collection shard key events. Thanks to @qhello for bringing this bug to our attention!

CommandSucceededEvent and CommandFailedEvent events now have a databaseName property

CommandSucceededEvent and CommandFailedEvent now include the name of the database against which the command was executed.

Deprecations

Transaction state getters are deprecated

These were for internal use only and include:

Transaction#options
Transaction#recoveryToken
Transaction#isPinned
Transaction#isStarting
Transaction#isActive
Transaction#isCommitted

ClientMetadata, ClientMetadataOptions, and CancellationToken have been deprecated

These types will be removed in an upcoming major version of the driver.

CommandOptions.noResponse is deprecated

Caution

noResponse is not intended for use outside of MongoClient.close(). Do not use this option.

The Node driver has historically supported an option, noResponse, that is used internally when a MongoClient is closed. This option was accidentally public. This option will be removed in an upcoming major release.

Features

• NODE-5055: Add databaseName property to command monitoring events (#4586) (3faf0c9)
• NODE-7009: add client metadata on demand (#4574) (b9636ee)
• NODE-7053: deprecate noResponse option (#4589) (1115319)
• NODE-6865: deprecate transaction getters (#4567) (da46aea)
• NODE-6991: deprecate unintentionally public client metadata types (#4566) (ca6554b)

Bug Fixes

• NODE-4845: allocate sessions lazily in cursors (#4575) (5761703)
• NODE-6589: background task does not prune idle connections when minPoolSize=0 (#4569) (7cbb641)
• NODE-6955: add missing wallTime property TS change stream event interfaces (#4541) (f153c6f)

Documentation

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We invite you to try the mongodb library immediately, and report any issues to the NODE project.

v6.17.0

6.17.0 (2025-06-03)

The MongoDB Node.js team is pleased to announce version 6.17.0 of the mongodb package!

Release Notes

Support for MongoDB 4.0 is removed

Warning

When the driver connects to a MongoDB server of version 4.0 or less, it will now throw an error.

OIDC machine workflows now retry on token expired errors during initial authentication

This resolves issues of a cached OIDC token in the driver causing initial authentication to fail when the token had expired. The affected environments were "azure", "gcp", and "k8s".

keepAliveInitialDelay may now be configured at the MongoClient level

When not present will default to 120 seconds. The option value must be specified in milliseconds.

import { MongoClient } from 'mongodb';

const client = new MongoClient(process.env.MONGODB_URI, { keepAliveInitialDelay: 100000 });

updateOne and replaceOne now support a sort option

The updateOne and replaceOne operations in each of the ways they can be performed support a sort option starting in MongoDB 8.0. The driver now supports the sort option the same way it does for find or findOneAndModify-style commands:

const sort = { fieldName: -1 };

collection.updateOne({}, {}, { sort });
collection.replaceOne({}, {}, { sort }); 

collection.bulkWrite([ 
  { updateOne: { filter: {}, update: {}, sort } },
  { replaceOne: { filter: {}, replacement: {}, sort } },
]);

client.bulkWrite([
  { name: 'updateOne', namespace: 'db.test', filter: {}, update: {}, sort },
  { name: 'replaceOne', namespace: 'db.test', filter: {}, replacement: {}, sort }
]);

MongoClient close shuts outstanding in-use connections

The MongoClient.close() method now shuts connections that are in-use allowing the event loop to close if the only remaining resource was the MongoClient.

Support Added for Configuring the DEK cache expiration time.

Default value is 60000. Requires using mongodb-client-encryption >= 6.4.0

For ClientEncryption:

import { MongoClient, ClientEncryption } from 'mongodb';
const client = new MongoClient(process.env.MONGODB_URI);
const clientEncryption = new ClientEncryption(client, { keyExpirationMS: 100000, kmsProviders: ... });

For auto encryption:

import { MongoClient, ClientEncryption } from 'mongodb';
const client = new MongoClient(process.env.MONGODB_URI, {
  autoEncryption: {
    keyExpirationMS: 100000,
    kmsProviders: ...
  }
});

Update operations will now throw if ignoreUndefined is true and all operations are undefined.

When using any of the following operations they will now throw if all atomic operations in the update are undefined and the ignoreUndefined option is true. This is to avoid accidental replacement of the entire document with an empty document. Examples of this scenario:

import { MongoClient } from 'mongodb';

const client = new MongoClient(process.env.MONGODB_URI);

client.bulkWrite(
  [
    {
      name: 'updateMany',
      namespace: 'foo.bar',
      filter: { age: { $lte: 5 } },
      update: { $set: undefined, $unset: undefined }
    }
  ],
  { ignoreUndefined: true }
);

const collection = client.db('test').collection('test');

collection.bulkWrite(
  [
    {
      updateMany: {
        filter: { age: { $lte: 5 } },
        update: { $set: undefined, $unset: undefined }
      }
    }
  ],
  { ignoreUndefined: true }
);

collection.findOneAndUpdate(
  { a: 1 },
  { $set: undefined, $unset: undefined },
  { ignoreUndefined: true }
);

collection.updateOne({ a: 1 }, { $set: undefined, $unset: undefined }, { ignoreUndefined: true });

collection.updateMany({ a: 1 }, { $set: undefined, $unset: undefined }, { ignoreUndefined: true });

Socket errors are always treated as network errors

Network errors perform an important role in the driver, impacting topology monitoring processes and retryablity. A bug in the driver's socket implementation meant that in scenarios where server disconnects occurred while no operation was in progress on the socket resulted in errors that were not considered network errors.

Socket errors are now unconditionally treated as network errors.

Features

• NODE-6245: add keepAliveInitialDelay config (#4510) (d6c0eb3)
• NODE-6290: add sort support to updateOne and replaceOne (#4515) (28857b7)
• NODE-6882: eagerly close checked out connections when client is closed (#4499) (64fdb3e)
• NODE-6884: remove support for 4.0 (#4534) (6fe6ccc)
• NODE-6952: support configuring DEK cache expiration (#4538) (c529f07)
• NODE-6963: use BSON 6.10.4 (#4549) (aee490a)

Bug Fixes

• NODE-6638: throw if all atomic updates are undefined (#4519) (9625b2d)
• NODE-6864: socket errors are not always converted to MongoNetworkErrors (#4473) (2d86095)
• NODE-6962: OIDC machine workflows use OIDCCallbacks internally (#4546) (bd6030f)

Documentation

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• Changelog

We invite you to try the mongodb library immediately, and report any issues to the NODE project.

v6.16.0

6.16.0 (2025-04-21)

The MongoDB Node.js team is pleased to announce version 6.16.0 of the mongodb package!

Release Notes

distinct commands now support an index hint

The Collection.distinct() method now supports an optional hint, which can be used to tell the server which index to use for the command:

// providing an index description
await collection.distinct('my-key', { 
  hint: { 'my-key': 1 }
});

// providing an index name
await collection.distinct('my-key', { 
  hint: 'my-key'
});

This requires server 7.1+.

Driver support for servers <=4.0 deprecated

Warning

Node driver support for server 4.0 will be removed in an upcoming minor release. Reference: MongoDB Software Lifecycle Schedules.

Fix processing of multiple messages within one network data chunk

During elections, or other scenarios where the server is pushing multiple topology updates to the driver in a short period of time, a bug in the driver's socket code led to backlog of topology updates that would remain in the buffer until another heartbeat arrived from the server. This could lead to delays in the driver recovering from an election and/or an increase in MongoServerSelectionErrors.

Now, all messages in the current buffer are returned to the driver leading to faster processing times.

Huge thank you to @andreim-brd for sharing a self-contained reproduction that proved to be instrumental in the identification of the underlying issue!

FindCursor.rewind() throws documents?.clear() is not a function errors in certain scenarios

In certain scenarios where limit and batchSize are both set on a FindCursor, an internal driver optimization intended to prevent unnecessary requests to the server when the driver knows the cursor is exhausted would prevent the cursor from being rewound. This issue has been resolved.

Features

• NODE-6494: add support for hint on distinct commands (#4487) (40d0e87)
• NODE-6515: deprecate driver support for server 4.0 (#4517) (4c1a8a7)

Bug Fixes

• NODE-6630: read all messages in buffer when chunk arrives (#4512) (8c86e30)
• NODE-6878: documents.clear() throws a TypeError after cursor is rewound (#4488) (a1fffeb)

Documentation

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We invite you to try the mongodb library immediately, and report any issues to the NODE project.

v6.15.0

6.15.0 (2025-03-18)

The MongoDB Node.js team is pleased to announce version 6.15.0 of the mongodb package!

Release Notes

Support for custom AWS credential providers

The driver now supports a user supplied custom AWS credentials provider for both authentication and for KMS requests when using client side encryption. The signature for the custom provider must be of () => Promise<AWSCredentials> which matches that of the official AWS SDK provider API. Provider chains from the actual AWS SDK can also be provided, allowing users to customize any of those options.

Example for authentication with a provider chain from the AWS SDK:

import { fromNodeProviderChain } from '@aws-sdk/credential-providers';

const client = new MongoClient(process.env.MONGODB_URI, {
  authMechanismProperties: {
    AWS_CREDENTIAL_PROVIDER: fromNodeProviderChain()
  }
});

Example for using a custom provider for KMS requests only:

import { fromNodeProviderChain } from '@aws-sdk/credential-providers';

const client = new MongoClient(process.env.MONGODB_URI, {
  autoEncryption: {
    keyVaultNamespace: 'keyvault.datakeys',
    kmsProviders: { aws: {} },
    credentialProviders: {
      aws: fromNodeProviderChain()
    }
  }
}

Custom providers do not need to come from the AWS SDK, they just need to be an async function that returns credentials:

const client = new MongoClient(process.env.MONGODB_URI, {
  authMechanismProperties: {
    AWS_CREDENTIAL_PROVIDER: async () => {
      return {
        accessKeyId: process.env.ACCESS_KEY_ID,
        secretAccessKey: process.env.SECRET_ACCESS_KEY
      }
    }
  }
});

Fix misc unhandled rejections under special conditions

We identified an issue with our test suite that suppressed catching unhandled rejections and surfacing them to us so we can ensure the driver handles any possible rejections. Luckily only 3 cases were identified and each was under a flagged or specialized code path that may not have been in use:

• If the MongoClient was configured to use OIDC and an AbortSignal was aborted on cursor at the same time the client was reauthenticating, if the reauth process was rejected it would have been unhandled.
• If timeoutMS was used and the timeout expired before an operation reached the server selection step the operation would throw the expected timeout error but a promise representing the timeout would also raise an unhandled rejection.
• If a change stream was closed while processing a change event it was possible for the "change stream is closed" error to be emitted as an error event and reject an internal promise representing fetching the "next" change.

Features

• NODE-6141: allow custom aws sdk config (#4373) (3d047ed)

Bug Fixes

• NODE-6845: ensure internal rejections are handled (#4448) (06e941a)

Documentation

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We invite you to try the mongodb library immediately, and report any issues to the NODE project.

v6.14.2

6.14.2 (2025-03-04)

The MongoDB Node.js team is pleased to announce version 6.14.2 of the mongodb package!

Release Notes

KMS Requests can cause unhandled rejection

When using explicit encryption or automatic encryption, the driver makes requests to a Key Management System when to fetch key encryption keys. The driver supports connecting to a KMS provider through a Socks5 proxy. However, the socket used for the socks5 proxy was created in all circumstances, regardless of proxy configuration. This leads to unhandled rejection errors when closing the socket the driver attempts to clean up the unused socket.

With the changes in this release, the socket is only created if a proxy is configured and the any promises created for the proxy are properly handled.

Bug Fixes

• NODE-6803: kms proxy socket creates unhandled rejection (#4444) (ed69cf9)

Documentation

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We invite you to try the mongodb library immediately, and report any issues to the NODE project.

v6.14.1

6.14.1 (2025-03-03)

The MongoDB Node.js team is pleased to announce version 6.14.1 of the mongodb package!

Release Notes

Fixed occasional OIDC reauthentication failure

Error code 391 is intended to make the driver internally reauthenticate the connection to the server, however, occasionally this was being raised to the user. This was due to a bug in setting the cached access token on newly created connections.

Bug Fixes

• NODE-6801: set token on connection from cache (#4438) (cb13746)

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v6.14.0

6.14.0 (2025-02-28)

The MongoDB Node.js team is pleased to announce version 6.14.0 of the mongodb package!

Release Notes

Add support for $lookup on encrypted collections

Starting in the upcoming MongoDB server 8.1, the aggregation stage $lookup can now be used with clients configured for automatic encryption after upgrading to mongodb-client-encryption@>=6.3.0! 🔒 🎉

Use isUint8Array defined in the driver rather than util/types

Some users of bundlers for next.js and our very own mongosh noticed a new import from "util/types" that would need to be supported in environments that don't have that module. We already have an internal implementation of isUint8Array so we do not need to add an import for "util/types".

Revert @aws-sdk/credential-providers compatiblity change

In v6.13.1 we inadvertantly raised the version compatibility of @aws-sdk/credential-providers, that change has been reverted.

Features

• NODE-6676: add support for nsType in change stream create events (#4431) (7800067)
• NODE-6773: add support for $lookup with automatic encryption (#4427) (965b21a)

Bug Fixes

• NODE-6765: FindOneAndUpdateOptions supports aggregation expressions (#4423) (421ddeb)
• NODE-6792: use isUint8Array from driver's utils instead of util/types (#4436) (dfe1fba)
• NODE-6794: revert @aws-sdk/credential-providers peer compatibility change (#4437) (488c407)

Documentation

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v6.13.1

6.13.1 (2025-02-20)

The MongoDB Node.js team is pleased to announce version 6.13.1 of the mongodb package!

Release Notes

Remove extraneous Promise<Document> in Collection.replaceOne return type

The return type signature of the replaceOne method no longer includes the general Promise<Document> type. Thanks to @arturmuller, the replaceOne type signature is now more accurate! 🎉

Fix writeConcern omitted when timeoutMS is provided

When timeoutMS and a write concern were provided, the writeConcern was incorrectly omitted from the final command executed by the driver.

Thanks @stepanho for contributing the fix!

Update BSON version requirement to 6.10.3

This pulls in fixes made in bson versions 6.10.3 and 6.10.2 into the driver.

BSON 6.10.2 fixed an issue in calculateObjectSize ignoring the size contributed by BigInt values to a BSON document. This impacted batch splitting logic in bulkWrite operations: if the actual BSON was over the size returned by calculateObjectSize the server would return an error.

Warning

BSON 6.10.3 addresses a potential data corruption risk with the use of useBigInt64 flag introduced in BSON 6.4.0, where negative Long values would be deserialized into BigInt as unsigned integers when the useBigInt64 flag was enabled. (Thanks to @rkistner for reporting this issue!)

Bug Fixes

• NODE-6407: use conversationId returned from server in saslContinue (#4368) (fbefa6b)
• NODE-6613: Update error messages when primaries go stale (#4397) (6528c8d)
• NODE-6690: Remove extraneous Document in replaceOne return type (#4383) (6c81d4e)
• NODE-6763: pass WriteConcernOptions instead on WriteConcernSettings (#4421) (26f15d7)
• NODE-6777: update BSON to 6.10.3 (#4428) (db5b9e0)

Documentation

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