You can use a Cloud Tasks queue to regulate the rate of
[Workflows](https://docs.cloud.google.com/workflows/docs/overview.md.txt) executions.

For Workflows, there is a [maximum number](https://docs.cloud.google.com/workflows/quotas.md.txt) of
active workflow executions that can happen concurrently. After the limit is
reached, new executions fail with an HTTP `429 Too many requests` status code.
By enabling a Cloud Tasks queue to execute child workflows at a
rate that you define, you can avoid Workflows quota-related issues and
achieve a better execution rate.

For instructions on how to do this, see the [full tutorial in the
Workflows documentation](https://docs.cloud.google.com/workflows/docs/tutorials/buffer-workflows-executions).