# health

query · in the family [Open doors](/reference/open-doors/)

## What it does

Is the service alive — the plainest possible check. Reads nothing of yours.

A liveness read — no contract version required (reads may omit, SPEC_ENVELOPE).

## Who may call it

No key needed for this call.

## Returns

[String](/types/#scalars) `String!` — Text.

## Example request

```graphql
query ExampleHealth {
  health
}
```

## Example response

```json
{
  "data": {
    "health": "ok"
  },
  "extensions": {
    "at": {
      "callId": "01EXAMPLE-CALL-ID",
      "version": {
        "requested": null,
        "serviced": {
          "name": "genesis",
          "number": 0
        }
      }
    }
  }
}
```

## Errors this call can answer

- `RATE_LIMIT/THROTTLED` — Too many requests in a short time. ([RATE_LIMIT](/errors/RATE_LIMIT/))