MongoDB hosting integration

Use this integration to model, configure, and orchestrate a MongoDB resource in an Aspire solution.

Getting started

Add the integration

From your AppHost directory, add the Aspire.Hosting.MongoDB integration with the Aspire CLI:

aspire add Aspire.Hosting.MongoDB

Usage example

Then, in the AppHost, add a MongoDB server with a single-member replica set for local transactions and change streams. Add a database and reference it using the normal resource APIs:

Experimental: Replica set, keyfile, and TLS configuration APIs are marked ASPIREMONGODB001 and may change. C# AppHosts must explicitly opt in by suppressing this diagnostic where these APIs are used.

C#

#pragma warning disable ASPIREMONGODB001
var mongodb = builder.AddMongoDB("mongodb").WithReplicaSet();
#pragma warning restore ASPIREMONGODB001
var db = mongodb.AddDatabase("mydb");

var myService = builder.AddProject<Projects.MyService>("myservice")
                       .WithReference(db)
                       .WaitFor(db);

TypeScript

const mongodb = await builder.addMongoDB("mongodb").withReplicaSet();
const db = await mongodb.addDatabase("mydb");

const myService = await builder.addNodeApp("myService", "../my-service", "server.js")
    .withReference(db)
    .waitFor(db);

Omit WithReplicaSet() / withReplicaSet() when a standalone server is sufficient.

Interactive REPL

Call WithRepl() to opt into a REPL command on the MongoDB server resource in the dashboard:

builder.AddMongoDB("mongo").WithRepl();

await builder.addMongoDB("mongo").withRepl();

REPL access is disabled by default and is available only in run mode. Enable it only for trusted dashboard users: the shell uses the resource's configured credentials and is not read-only. Sharing the dashboard through a tunnel, Codespaces, or VS Code remote development also exposes this capability to users who can execute resource commands.

Use exit before closing the terminal tab to end the session cleanly. Closing the tab alone can leave mongosh running inside the container. Stopping the container also ends any remaining REPL processes.

Select the command while the container is running to open the bundled mongosh client in the terminal dock; no local MongoDB client installation is required.

The shell authenticates against admin using the configured credentials, passed through the environment rather than command-line arguments. It connects directly to the server inside its container, including replica set members. When TLS is enabled, it uses the configured certificate trust bundle and validates the server certificate for localhost. Custom certificates must cover localhost, and their issuing CA must be trusted through Aspire's certificate configuration. The command is not included in published applications.

Single-member replica set

WithReplicaSet() configures and initializes a single-member replica set on the same MongoDBServerResource; it is no longer just a low-level mongod option. No separate replica set resource is needed. AddDatabase, WithReference, and WaitFor continue to work with the server or its databases. Initialization runs during the resource lifecycle, not in health checks. Readiness waits for initialization and primary election, so consumers can use transactions and change streams after WaitFor.

The optional set name defaults to the server's Aspire resource name. To choose a different name:

C#

#pragma warning disable ASPIREMONGODB001
var mongodb = builder.AddMongoDB("mongodb").WithReplicaSet("app-rs");
#pragma warning restore ASPIREMONGODB001

TypeScript

const mongodb = await builder.addMongoDB("mongodb").withReplicaSet({ name: "app-rs" });

Repeating the same configuration is a no-op; a conflicting name throws. Omitting the name on a later call preserves the previously configured name.

Consumer connection strings use the server's normal endpoint with directConnection=true and the driver's default primary read preference. This path does not use topology discovery, split-horizon addresses, or fixed host ports. It preserves normal automatic TLS behavior but does not require a developer certificate or insecure TLS flags.

Keyfiles and persistence

MongoDB requires a keyfile when authentication and replication are enabled, even with one member. WithReplicaSet() generates a secret keyfile if none is configured. To supply your own keyfile content, pass a secret parameter to WithKeyFile before calling WithReplicaSet:

C#

var keyfile = builder.AddParameter("mongo-keyfile", secret: true);
#pragma warning disable ASPIREMONGODB001
var mongodb = builder.AddMongoDB("mongodb")
    .WithKeyFile(keyfile.Resource)
    .WithReplicaSet();
#pragma warning restore ASPIREMONGODB001

TypeScript

const keyfile = await builder.addParameter("mongo-keyfile", { secret: true });
const mongodb = await builder.addMongoDB("mongodb")
    .withKeyFile(keyfile)
    .withReplicaSet();

The parameter supplies the file's contents, not a host file path. Contents must satisfy MongoDB's keyfile requirements. The file is mounted inside the container at /etc/rs.key by default with restricted permissions. It authenticates replica set members and does not replace the username and password used by applications. Supplying a different keyfile after WithReplicaSet() conflicts with the generated keyfile and throws; repeating the same explicit keyfile parameter and container path is a no-op.

Use WithDataVolume() or WithDataBindMount() to persist data. MongoDB only applies initial credentials to an empty data directory, so keep the configured credentials and replica set identity unchanged when reusing data. With the default set name, renaming the Aspire resource also changes the set identity. Existing compatible single-member data is reused without forced reconfiguration; mismatched set names, member addresses, or multi-member data are rejected. Preserve the original configuration or deliberately start with an empty development volume rather than expecting automatic migration.

Advanced multi-member experiments

AddMongoDBReplicaSet(...).WithMember(...) is a separate experimental path for local multi-member replication experiments, not a production-ready deployment model. Use it when exploring replication or elections across multiple containers, not merely to enable transactions or change streams. Production topology and deployment projection require separate support.

Create plain MongoDB servers and let WithMember configure their shared replication settings. Do not call WithReplicaSet on these servers: a single-member set configured that way cannot be adopted by the advanced API, and WithMember rejects it even if the set names match.

C#

var mongo1 = builder.AddMongoDB("mongo-1");
var mongo2 = builder.AddMongoDB("mongo-2");
var mongo3 = builder.AddMongoDB("mongo-3");

#pragma warning disable ASPIREMONGODB001
var replicaSet = builder.AddMongoDBReplicaSet("rs0")
                        .WithMember(mongo1)
                        .WithMember(mongo2)
                        .WithMember(mongo3);

var myService = builder.AddProject<Projects.MyService>("myservice")
                       .WithReference(replicaSet)
                       .WaitFor(replicaSet);
#pragma warning restore ASPIREMONGODB001

TypeScript

const mongo1 = await builder.addMongoDB("mongo-1");
const mongo2 = await builder.addMongoDB("mongo-2");
const mongo3 = await builder.addMongoDB("mongo-3");

const replicaSet = await builder.addMongoDBReplicaSet("rs0")
    .withMember(mongo1)
    .withMember(mongo2)
    .withMember(mongo3);

const myService = await builder.addNodeApp("myService", "../my-service", "server.js")
    .withReference(replicaSet)
    .waitFor(replicaSet);

Reference and wait for the advanced replica set resource, rather than an individual member. A replica set holds at most 50 members, the first seven of which vote in elections; the rest join as non-voting members that still carry a full copy of the data.

Members share credentials and a keyfile owned by the advanced replica set. Pass a username or password to AddMongoDBReplicaSet, not to individual members; conflicting credentials or member-specific keyfiles are rejected. Existing volumes retain their original credentials, so use matching credential parameters or intentionally start with empty development volumes. This does not migrate an existing single-member set into the advanced topology.

Publish limitation

Both replica set paths are supported only for local runs. WithReplicaSet and AddMongoDBReplicaSet reject publish mode as unsupported, rather than being silently excluded or becoming no-ops. WithKeyFile and the TLS configuration methods also reject publish mode. Applications using these configurations cannot be published or deployed yet; production deployment projection is separate work.

TLS

A MongoDB server serves TLS whenever an HTTPS/TLS certificate is available for it, which by default is the ASP.NET Core developer certificate. WithoutHttpsCertificate() opts out and WithTlsMode() chooses how strict the server is about TLS on incoming connections. The connection string reports this through a tls=true flag that is resolved when the connection string is read, so consumers pick it up automatically.

The developer certificate is issued for localhost, so a consumer running on the host validates it without any further configuration. A consumer running in a container is a different matter: it reaches the server by its resource name on the container network, which is not a name the certificate carries, so its TLS handshake fails host name validation. Until certificates covering container network names are available, a containerized consumer of a TLS-enabled MongoDB server has to be configured to relax host name validation.

WithoutHttpsCertificate() can opt out of TLS for either a standalone server or the simple WithReplicaSet() path. The single-member path does not require TLS and does not automatically enable WithTlsAllowInvalidCertificates(). When TLS is available, consumers still need to trust the certificate and connect using a hostname it covers.

Only the advanced AddMongoDBReplicaSet(...).WithMember(...) path requires TLS for split-horizon addressing: host-reachable addresses are selected using the incoming connection's SNI, and a member without TLS fails initialization. Its current member configuration relaxes peer certificate validation, and containerized clients need certificates covering container network names or development-only hostname-validation relaxation. These limitations are another reason to keep this path for local experiments.

Connection Properties

When you reference a MongoDB resource using WithReference, the following connection properties are made available to the consuming project:

MongoDB server

The MongoDB server resource exposes the following connection properties:

With WithReplicaSet(), this remains a server resource with a single Host and Port; its URI adds directConnection=true and keeps the default primary read preference. TLS adds tls=true when enabled.

MongoDB database

The MongoDB database resource combines the server properties above and adds the following connection property:

Advanced MongoDB replica set

The resource returned by AddMongoDBReplicaSet exposes the following connection properties. Unlike the server configured with WithReplicaSet, it has no single Host and Port, because clients discover the members through the seed list carried in the Uri:

Aspire exposes each property as an environment variable named [RESOURCE]_[PROPERTY]. For instance, the Uri property of a resource called db1 becomes DB1_URI.

Additional documentation

• https://aspire.dev/integrations/gallery/
• https://aspire.dev/integrations/databases/mongodb/mongodb-host/

Feedback & contributing

https://github.com/microsoft/aspire