> ## Documentation Index
> Fetch the complete documentation index at: https://docs.condense.io/llms.txt
> Use this file to discover all available pages before exploring further.

# MongoDB (Input, Store)

**Connector Type:** Input Connector

**Description**

Polls data from MongoDB into Condense for analytics, modeling, and dashboarding.

**Brief Description**

The **MongoDB Change Data Capture (CDC) Stream Input Connector** enables Condense to ingest real-time change events from MongoDB databases into Kafka-native topics for downstream processing, analytics, and transformations. It captures **insert, update, and delete** operations from MongoDB collections and streams them into Condense topics with minimal latency.

This connector is designed for applications requiring continuous synchronization between operational databases and event-driven platforms, such as analytics pipelines, real-time monitoring, or microservices that react to database changes.

**Links to Relevant Documents**

* [https://www.mongodb.com/docs/manual/changeStreams/](https://www.mongodb.com/docs/manual/changeStreams/)
* [https://www.mongodb.com/docs/kafka-connector/current/](https://www.mongodb.com/docs/kafka-connector/current/)

**Connector Overview**

| **Feature**         | **Value**                                                 |
| :------------------ | :-------------------------------------------------------- |
| Connector Type      | Input                                                     |
| Stream Type         | Database Change Data Capture (CDC)                        |
| Supported MongoDB   | Replica Sets / Sharded Clusters (Atlas or self-managed)   |
| Operations Captured | Insert, Update, Delete                                    |
| Supported Kafka     | Apache Kafka 3.8.0+ via Condense platform                 |
| Authentication      | Username/Password, TLS certificates                       |
| Output              | Publishes change events to Condense topics in JSON format |

**Core Functionality**

* **Real-time Change Data Capture** – Streams inserts, updates, and deletes as events.
* **Full Document Mode** – Supports capturing the complete changed document in addition to deltas.
* **Batch Polling** – Groups events into configurable batch sizes for efficient ingestion.
* **Flexible Mapping** – Allows namespace mapping (database.collection → topic).
* **Scalable** – Horizontally scalable using Condense Kafka-native architecture.
* **Fault-Tolerant** – Supports resume tokens to recover from interruptions without data loss.

**How MongoDB CDC Input Works in Condense**

1. **Connection Established** – Connector connects to MongoDB using the provided URI.
2. **Change Stream Subscription** – Subscribes to a collection's Change Stream.
3. **Event Capture** – Detects insert, update, and delete operations.
4. **Batch Aggregation** – Buffers events up to Poll Max Batch Size before pushing.
5. **Publishing to Condense** – Events are converted to JSON and published into the configured Condense Kafka topic.

**Configuration**

| **Category** | **Field Name**      | **Description**                                                           | **Required** |
| :----------- | :------------------ | :------------------------------------------------------------------------ | :----------: |
| General      | Title               | A unique name for the connector instance within Condense                  |      Yes     |
| Connection   | Connection URI      | MongoDB connection string with authentication and database details        |      Yes     |
| Database     | Database Name       | The MongoDB database to monitor                                           |      Yes     |
| Database     | Collection Name     | The MongoDB collection from which changes will be captured                |      Yes     |
| CDC          | Full Document Mode  | Determines whether the full updated document is included in change events |      Yes     |
| CDC          | Poll Max Batch Size | Maximum number of documents processed per polling cycle                   |      Yes     |
| Condense     | Output Topic        | Condense Kafka topic where MongoDB change events will be published        |      Yes     |

**Field-by-Field Explanation**

**1. Title**

* **Description:** A unique name for the connector instance within Condense.
* **Example:** `MongoDB_CDC_Input_Orders`

***

**2. Connection URI**

* **Description:** MongoDB connection string with authentication and database details.
* **How to Obtain:**
  * For MongoDB Atlas → Copy from **Cluster → Connect → Connect your application**.
  * For self-hosted MongoDB → Format:

```text theme={null}
mongodb://username:password@host:port/database
```

* **Example:**

```text theme={null}
mongodb://cdcuser:cdcpass@cluster0.mongodb.net:27017/myapp
```

***

**3. Database Name**

* **Description:** The MongoDB database to monitor.
* **Example:** `salesdb`

***

**4. Collection Name**

* **Description:** The MongoDB collection from which changes will be captured.
* **Example:** `orders`

***

**5. Full Document Mode**

* **Description:** Determines whether the full updated document is included in change events.
* **Options:**
  * `off` → Only delta/change fields are included.
  * `updateLookup` → Full document returned on updates.
* **Example:** `updateLookup`

***

**6. Poll Max Batch Size**

* **Description:** Maximum number of documents processed per polling cycle.
* **Default:** `1000`
* **Example:** `500`

***

**7. Output Topic**

* **Description:** Condense Kafka topic where MongoDB change events will be published.
* **How to Obtain:** Select an existing topic from the Condense Topics Dashboard.
* **Example:** `mongodb_order_changes`

**Sample Configuration Example**

```json theme={null}
{
  "title": "MongoDB_CDC_Input_Orders",
  "connectionUri": "mongodb://cdcuser:cdcpass@cluster0.mongodb.net:27017/salesdb",
  "databaseName": "salesdb",
  "collectionName": "orders",
  "fullDocumentMode": "updateLookup",
  "pollMaxBatchSize": 500,
  "outputTopic": "mongodb_order_changes"
}
```

**Troubleshooting and Common Issues**

**Connector not starting**

* Check MongoDB URI format and credentials.
* Ensure the database and collection exist.
* Verify that Change Streams are enabled (requires replica set/sharded cluster).

**No messages in topic**

* Confirm that test data is being inserted into the monitored collection.
* Check if poll batch size is too restrictive.

**Schema wrapper in messages**

* Enable raw JSON mode in configuration.

**Connection timeout**

* Verify MongoDB Atlas IP whitelist settings.
* Ensure network connectivity between Condense and MongoDB cluster.

**Advanced Topics**

**1. Performance Tuning**

* Adjust Poll Max Batch Size and polling intervals for optimal throughput.

**2. Resume Tokens**

* Enables recovery from interruptions without reprocessing old data.

**3. Filtering**

* Use MongoDB aggregation pipelines to filter out unnecessary events before they are published.

**4. Security**

* Always use TLS-encrypted URIs and restrict database users to least-privilege roles.

**Best Practices**

1. Use TLS-encrypted MongoDB connections.
2. Configure dedicated users with least-privilege permissions.
3. Monitor connector lag and throughput.
4. Tune Poll Max Batch Size based on expected change volume.
5. Use separate Condense topics for different collections or business domains.