API rate limited without 429
Verdict
When an API limits your requests without returning HTTP 429, this behavior is intentional and not a client-side error.
If requests continue to be accepted while their effects degrade, delay, or disappear, increasing client-side pressure will not restore normal behavior.
At this point, rate limiting is occurring at the execution level, not the request level.
Why This Happens
Many systems protect themselves by limiting impact, not access.
Common mechanisms include:
- Silent throttling, where requests are accepted but deprioritized
- Behavior-based limits triggered by usage patterns
- Queue protection, where downstream processing is constrained
- Adaptive capacity management under load
These controls are internal and opaque. They are not reliably signaled through status codes.
Where You Can Stop
Once this pattern is observed consistently, you can reasonably stop:
- Increasing request frequency to “push through”
- Adding retries for accepted requests
- Assuming absence of 429 implies absence of limits
- Treating reduced impact as a client logic defect
Further pressure typically reinforces throttling rather than bypassing it.
What This Page Is Not
This page does not:
- Reveal rate limit thresholds
- Provide evasion techniques
- Recommend pacing or backoff strategies
Its purpose is to clarify when lack of explicit rejection does not imply lack of limiting.
Not all limits are announced.