> ## Documentation Index
> Fetch the complete documentation index at: https://docs.moss.dev/llms.txt
> Use this file to discover all available pages before exploring further.
# Sub-10ms Knowledge Retrieval
> Load an index into memory and run semantic queries in-process.
Moss loads an index into memory and runs embedding and search in-process, so a query is a
local call with no network round trip per operation. The pattern is the same in every SDK:
load the index once, then query it.
```ts theme={null}
await client.loadIndex(indexName)
const results = await client.query(indexName, 'How do I return a damaged product?', { topK: 3 })
```
Queries run against the in-memory index and embed the query text with a local model.
## The query pipeline
* Load the index once, then query it in-process.
* Optional background sync to the cloud.
* Query pipeline: text -> embed -> retrieve -> rerank (optional).
## Prerequisites
* Node.js 18+ or Python 3.10+
* Moss credentials: `MOSS_PROJECT_ID`, `MOSS_PROJECT_KEY`
* An index to query (create `faqs` via the [Quickstart](/docs/start/quickstart) if you don't have one yet)
## Steps
```bash theme={null}
export MOSS_PROJECT_ID=your_project_id
export MOSS_PROJECT_KEY=your_project_key
export MOSS_INDEX_NAME=faqs # or your index
```
Ensure the index exists (see [Quickstart](/docs/start/quickstart) to create `faqs`).
Run one of the snippets below.
## Run the sample (JavaScript or Python)
```ts JavaScript theme={null}
import { MossClient } from '@moss-dev/moss'
const client = new MossClient(
process.env.MOSS_PROJECT_ID!,
process.env.MOSS_PROJECT_KEY!
)
const indexName = process.env.MOSS_INDEX_NAME || 'faqs' // ensure this exists (see Quickstart)
async function main() {
await client.loadIndex(indexName)
const results = await client.query(indexName, 'How do I return a damaged product?', { topK: 3 })
console.log(`Found ${results.docs.length} docs in ${results.timeTakenInMs}ms`)
results.docs.forEach((doc, i) => {
console.log(`${i + 1}. [${doc.id}] ${doc.text} (score: ${doc.score.toFixed(3)})`)
})
}
main().catch(console.error)
```
```python Python theme={null}
import os
import asyncio
from moss import MossClient, QueryOptions
project_id = os.getenv("MOSS_PROJECT_ID")
project_key = os.getenv("MOSS_PROJECT_KEY")
index_name = os.getenv("MOSS_INDEX_NAME", "faqs") # ensure this exists (see Quickstart)
async def main():
client = MossClient(project_id, project_key)
await client.load_index(index_name)
results = await client.query(index_name, "How do I return a damaged product?", QueryOptions(top_k=3))
print(f"Found {len(results.docs)} docs")
for i, doc in enumerate(results.docs, 1):
print(f"{i}. [{doc.id}] {doc.text} (score: {doc.score:.3f})")
asyncio.run(main())
```
The sample loads your index into memory and returns the top matches. An index must be loaded
with `loadIndex` / `load_index` (or opened as a session) before you can query it.
