Hi @Sadat
good question here. A 429 from HubSpot normally just means you’ve hit the documented limits on the API (for example the CRM Search API has both a per-second and per-day quota: API usage guidelines and limits - HubSpot docs
In this case though, you and several others were seeing 429s even when under those limits so this was indeed a HubSpot side issue, and it’s now been resolved (confirmed on their status page).
For future builds it’s worth planning for this kind of hiccup. Even when you’re inside the quota, APIs can throttle or misbehave for short periods.
Best practice is to add exponential backoff and queuing so that transient 429s don’t break your app. HubSpot’s own docs on retry logic are here: API usage guidelines and limits - HubSpot docs
That’s actually one of the reasons we built Stacksync. It acts as a managed sync layer that automatically handles retries, backoff, and resiliency for HubSpot integrations. So if HubSpot throws unexpected 429s, the sync just pauses and resumes safely instead of stalling your systems.
Teams using it avoid having to code and maintain all that middleware themselves.
Hope that clarifies why you saw the errors and how to make your integrations a bit more resilient going forward.