Stuck on a token refresh loop in our Kotlin backend service. We’re building a server-side reporting tool that pulls conversation analytics via GET /api/v2/analytics/conversations/details/query. The docs suggest using the Client Credentials grant for server-to-server apps, so I set up the oauth2/token call with our client_id and client_secret.
The initial token request works fine. I get a 200 OK and a valid access_token. But when that token expires, my refresh logic kicks in. I’m reusing the same client_id and client_secret to request a new token. The API returns a new token, but immediately after, the subsequent analytics API call fails with a 401 Unauthorized. The error payload says "reason": "invalid_token".
I checked the expires_in field (3600 seconds) and my code waits until 3500 seconds before retrying the token fetch. Here’s the token request logic:
val response = client.post("https://api.mypurecloud.com/oauth2/token") {
contentType(ContentType.Application.FormUrlEncoded)
setBody(
formData {
append("grant_type", "client_credentials")
append("client_id", config.clientId)
append("client_secret", config.clientSecret)
}
)
}
Is the Client Credentials grant actually meant for long-lived reporting apps? Or should I be using Authorization Code with PKCE even for a backend service? The token keeps dying faster than I can refresh it.
The root cause here is likely how you’re handling the expiration timestamp. The expires_in field from the Genesys Cloud OAuth response is in seconds, but if you’re storing the raw token response or parsing it incorrectly, your refresh logic might trigger too early or too late. You also need to ensure you’re not blocking the main thread while waiting for the token, especially in a reporting tool that might be pulling large datasets.
Here is a solid way to handle this in Kotlin using khttp or standard HttpURLConnection. I prefer standard library calls to keep dependencies light.
import java.net.HttpURLConnection
import java.net.URL
import java.nio.charset.StandardCharsets
import java.util.Base64
fun refreshToken(clientId: String, clientSecret: String): String {
val url = URL("https://api.mypurecloud.com/oauth/token")
val connection = url.openConnection() as HttpURLConnection
connection.requestMethod = "POST"
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded")
// Basic Auth header for client credentials
val credentials = Base64.getEncoder().encodeToString("$clientId:$clientSecret".toByteArray(StandardCharsets.UTF_8))
connection.setRequestProperty("Authorization", "Basic $credentials")
val payload = "grant_type=client_credentials&scope=analytics:conversation:view"
connection.doOutput = true
connection.outputStream.write(payload.toByteArray(StandardCharsets.UTF_8))
val responseCode = connection.responseCode
if (responseCode == 200) {
val response = connection.inputStream.bufferedReader().readText()
// Parse JSON to extract access_token. Use Gson or Moshi here.
// Don't forget to store the expires_in value to calculate next refresh time.
return response
} else {
throw Exception("Token refresh failed: $responseCode")
}
}
Make sure you cache the token and subtract a few minutes from the expires_in value before scheduling the next refresh. This prevents race conditions where a request goes out with an expired token right as it expires. If you’re hitting rate limits, add a small retry mechanism with exponential backoff. The scope analytics:conversation:view is mandatory for the endpoint you mentioned. Check your scope configuration in the Genesys Cloud admin portal if you get a 403 after getting the token.