Azure App Configuration throttled HTTP 429 even though hourly request count is far below limit

TL;DR

An App Configuration store shows throttling (HTTP 429) while the hourly request total (about 2k) is far below the 30k limit. The expectation was that throttling only happens at the hourly cap.

Steps

1. Throttling is not only hourly: you can get 429s from exceeding the daily limit on the Free tier, the hourly limit on Standard, momentary throttling from a large burst of requests, excessive bandwidth, or hitting the storage quota. A burst of requests in a short window triggers throttling even with a low hourly total. The official guidance is that momentary throttling can usually be ignored, App Configuration clients (Azure SDK, configuration provider libraries, pipeline tasks) have built-in retry logic and will ride through it unnoticed.
2. Mined from a verified thread: https://vectle.com/threads/thr_eIkA2qRPb2uDDUMuzgJlIA (original: https://github.com/Azure/AppConfiguration/issues/736)

When to use

You are seeing this: An App Configuration store shows throttling (HTTP 429) while the hourly request total (about 2k) is far below the 30k limit. Use this skill when you run into "Azure App Configuration throttled HTTP 429 even though hourly request count is far below limit".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Sources

• https://github.com/Azure/AppConfiguration/issues/736

In the thread, the asker reported: An App Configuration store shows throttling (HTTP 429) while the hourly request total (about 2k) is far below the 30k limit. The expectation was that throttling only happens at the hourly cap. The verified answer that resolved it: Throttling is not only hourly: you can get 429s from exceeding the daily limit on the Free tier, the hourly limit on Standard, momentary throttling from a large burst of requests, excessive bandwidth, or hitting the storage quota. A burst of requests in a short window triggers throttling even with a low hourly total. The official guidance is that momentary throttling can usually be ignored, App Configuration clients (Azure SDK, configuration provider libraries, pipeline tasks) have built-in retry logic and will ride through it unnoticed.

Source: https://github.com/Azure/AppConfiguration/issues/736 Thread: https://vectle.com/threads/thr_eIkA2qRPb2uDDUMuzgJlIA