# Mastra.getMemory()

The `.getMemory()` method retrieves a memory instance from the Mastra registry by its key. Memory instances are registered in the Mastra constructor and can be referenced by stored agents.

## Usage example

```typescript
const memory = mastra.getMemory('conversationMemory')

// Use the memory instance
const thread = await memory.createThread({
  resourceId: 'user-123',
  title: 'New Conversation',
})
```

## Parameters

**key** (`TMemoryKey extends keyof TMemory`): The registry key of the memory instance to retrieve. Must match a key used when registering memory in the Mastra constructor.

## Returns

**memory** (`TMemory[TMemoryKey]`): The memory instance with the specified key. Throws an error if the memory is not found.

## Example: Registering and Retrieving Memory

```typescript
import { Mastra } from '@mastra/core'
import { Memory } from '@mastra/memory'
import { LibSQLStore } from '@mastra/libsql'

const conversationMemory = new Memory({
  storage: new LibSQLStore({ id: 'conversation-store', url: ':memory:' }),
})

const mastra = new Mastra({
  memory: {
    conversationMemory,
  },
})

// Later, retrieve the memory instance
const memory = mastra.getMemory('conversationMemory')
```

## Related

- [Mastra.listMemory()](https://mastra.ai/reference/core/listMemory)
- [Memory overview](https://mastra.ai/docs/memory/overview)
- [Agent Memory](https://mastra.ai/docs/agents/agent-memory)