Hi @rob-aitken ,
Thanks for using FusionAuth!
If you are seeing a 429 and are using FusionAuth cloud, you are being rate limited by our web application firewall. Our rate limits are not publicly available and may change over time, but are pretty generous. I'd check to make sure you are calling FusionAuth appropriately and/or using exponential backoff when getting a 429.
You can also file a support ticket using the account portal if that's helpful.
More information here: https://fusionauth.io/docs/v1/tech/installation-guide/cloud#captcha-and-rate-limits