Advanced

Retry logic

Algolia’s architecture is heavily redundant, to provide optimal reliability. Every application is hosted on at least three different servers (called clusters). As a developer, however, you don’t need to worry about those details. The API Client handles them for you:

• It leverages our dynamic DSN to perform automatic load balancing between servers.
• Its retry logic switches the targeted server whenever it detects that one of them is down or unreachable. Therefore, a given request will not fail unless all servers are down or unreachable at the same time.

Application-level errors (e.g. invalid query) are still reported without retry.

Error handling

Requests can fail for two main reasons:

1. Network issues: the server could not be reached, or did not answer within the timeout.
2. Application error: the server rejected the request.

In the latter case, the error reported by the API client contains:

• message: an error message indicating the cause of the error
• status: an HTTP status code indicating the type of error

Here’s an example:

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{
  "message":"Invalid Application ID",
  "status":404
}

The error message is purely informational and intended for the developer. You should never rely on its content programmatically, as it may change without notice.