# Via HTTP

Query an instance with cURL or any HTTP client, and the request size limits that apply per endpoint.

Instances serve the [HTTP API](/docs/reference/rest-api.md), so anything that speaks HTTP can query them.

That includes cURL, Postman, a serverless function, and a language without an SDK.

To get the URL, open the instance in [SurrealDB Studio](https://app.surrealdb.com), select **Connect**, then select **HTTP cURL**.

![The Connect menu in SurrealDB Studio with HTTP cURL selected, showing a generated cURL command containing the instance endpoint and its namespace and database headers.](~/assets/img/image/cloud/open-in-http.png)

> [!NOTE]
> The generated command is cURL, but the URL and headers work in any HTTP client. Paste them into Postman or your own code unchanged.

## Send a query

Post SurrealQL to `/sql`. Name the namespace and database in headers, and authenticate with a bearer token:

```bash title="Run a query over HTTP"
curl -X POST "https://<endpoint>/sql" \
  -H "Surreal-NS: main" \
  -H "Surreal-DB: main" \
  -H "Authorization: Bearer <token>" \
  -H "Accept: application/json" \
  -d "SELECT * FROM person LIMIT 10;"
```

The response is a JSON array with one result object per statement in the request.

## Request size limits

Instances run the SurrealDB defaults for request size, and those defaults differ per endpoint.

| Endpoint | Limit |
| --- | --- |
| `/sql` | 1 MiB |
| `/rpc` | 4 MiB |
| `/import` | 4 GiB |
| WebSocket message | 128 MiB |

A request over the cap is rejected with `413 Payload Too Large`. The 1 MiB cap on `/sql` is the one large queries tend to reach first.

If a payload does not fit, you have three options:

- **Use an SDK.** Most, including [Rust](/docs/reference/rust.md) and [JavaScript](/docs/reference/javascript.md), default to the WebSocket engine and its 128 MiB per message.
- **Stay on HTTP but change endpoint.** Send the query through [`POST /rpc`](/docs/reference/rest-api/rpc-protocol.md), which accepts 4 MiB.
- **Load bulk data through import.** [`POST /import`](/docs/reference/rest-api/http-protocol.md#import) accepts up to 4 GiB per request. See [Import and export](/docs/manage/instances/import-and-export.md#size-limits).

The full table is in [request size limits](/docs/reference/rest-api/http-protocol.md#request-size-limits). A self-hosted server sets these caps with environment variables. Instances run the defaults.