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

# Error handling and edge cases

> Handling errors when working with the DRN

There are certain errors that are possible when working with the DRN API:

## General error format

When the DRN API cannot process your request, it will return an error in the following format:

```json JSON theme={"theme":"github-dark-dimmed"}
{
  "error": {
    "code": "fixed_code",
    "message": "descriptive error message"
  }
}
```

The `code` is fixed inside a version, but the `message` can be updated to be more clear. Only the `code` value compatibility is guaranteed inside a specific [version](/reference/drn-api-versioning) !

For specific errors related to authentication, versioning, and rate limiting please refer to the specific reference pages.

## Unknown resource path

If a request is made to an unknown resource path (the part after the domain), an HTTP 404 error will be returned:

```json JSON theme={"theme":"github-dark-dimmed"}
// HTTP Status 404
{
  "error": {
    "code": "http.not_found",
    "message": "not found"
}
```

The only valid resource path (the part that goes after fpjs.io) is `drn`:

**`GET https://drn-api.fpjs.io/drn/{visitor_id}`**

## Invalid `visitor_id` parameter.

If the `visitor_id` parameter that was provided is not known to the DRN API, e.g. if it's not generated by our Android SDK or is unknown entirely, an HTTP 404 error will be returned:

```json JSON theme={"theme":"github-dark-dimmed"}
// HTTP Status 404
{
  "error": {
    "code": "http.not_found",
    "message": "visitor_id is not found"
  }
}
```

## Invalid `signals` parameter

A request without at least one `signals` parameter will return an HTTP 400 error:

```json JSON theme={"theme":"github-dark-dimmed"}
// HTTP Status 400
{
  "error": {
    "code": "invalid_signals_parameter",
    "message": "Invalid `signals` query parameter"
}
```

## Empty response

If you requested the signals from a device with activity older than 30 days, you'll get an empty state response:

```json JSON theme={"theme":"github-dark-dimmed"}
"regionalActivity": [
  // will be at 30 days in the past in RFC3369 format, UTC timezone
  "startDate": "2024-09-01T23:12:59Z",
  "endDate": "2024-10-01T23:12:59Z",
  "countries": []
},
"suspectScore": {
  // will be at 30 days in the past in RFC3369 format, UTC timezone
  "startDate": "2024-09-01T23:12:59Z",
  "endDate": "2024-10-01T23:12:59Z",
  "minimum": {
    "value": 0,
    "signals": {}
  },
  "maximum": {
    "value": 0,
    "percentile": 0
    "signals": {}
  }
},
"timestamps": {
  "firstSeenAt": "2024-09-01T00:00:00Z" // format RFC3339, equal to current API version 
  "lastSeenAt": "2024-09-01T00:00:00Z" // format RFC3339, equal to current API version
  }
```