Client Credentials vs Auth Code for Server-Side Reporting App

Building a C# service to pull conversation aggregates every night. The app runs on an Azure Function, no user interaction. The docs say “For server-to-server communication, use the client credentials flow.” So I’m using PlatformClientFactory.Create() with the API key and secret. It works fine for small queries. But when I try to hit /api/v2/analytics/conversations/details/query with a large date range, I get a 429 Too Many Requests error. The response header says X-RateLimit-Reset: 1234567890. I thought client credentials had higher limits than auth code. Is that wrong? I’ve seen other posts suggesting auth code with a service account, but that seems overkill for a headless job. The .NET SDK doesn’t expose a way to switch grant types easily without re-initializing the client.

Here is the code I’m using:

cvar client = PlatformClientFactory.Create();
client.SetOAuthClientCredentials("key", "secret");
var result = await client.AnalyticsApi.GetAnalyticsConversationsDetailsQuery(...);

The error happens immediately on the second page. Am I stuck with client credentials? If I switch to auth code, how do I handle token refresh in a stateless Azure Function? The docs are vague on the rate limit differences between the two flows. I just need a reliable way to get data without hitting the wall every time the query grows.

Webhooks don’t care about your auth flow, but they do care about timing. If your Azure Function is hammering the analytics endpoint before the webhook payload settles, you’re gonna get throttled. Add a Retry-After header check in your C# code. It’s not elegant, but it stops the 429s.