I found "rate limit" and "burst limit" at Design section of API Designer,
What is the difference of them?
Rate limit can be set at second, minute, hour, day an week time interval. On the other hand, burst limit can be set only second and minute time interval.
Does it mean same to set 1/1sec rate limit and to set 1/1sec burst limit?
Different Plans can have differing rate limits, both between operations and for the overall limit. This is useful for providing differing levels of service to customers. For example, a "Demo Plan" might enforce a rate limit of ten calls per minute, while a "Full Plan" might permit up to 1000 calls per second.
You can apply burst limits to your Plans, to prevent usage spikes that might damage infrastructure. Multiple burst limits can be set per Plan, at second and minute time intervals.
That said, these two parameters have a different meaning and could be used together. E.g.: I want to permit a total of 1000 calls per hour (rate limit) and a maximum spike of 50 calls per second (burst limit).
Rate limit enforce how many calls (total) are possible for a given time frame. After that the calls are not possible anymore. This is to create staged plans with different limits and charges (like e.g. entry or free, medium, enterprise).
Burst limits are used to manage, e.g., system load by capping the maximum calls for a moment (hence seconds or minutes), to prevent usage spikes. They can be used to make sure the allowed number of API calls (the rate limit) is evenly spread across the set time frame (day, week, month). They can also be used to protect the backend system from overloading.
So you could set a rate limit of 1000 API calls for a week and the burst limit to 100 calls a minute. If there were 10 "heavy" minutes, the entire rate would have been consumed. An user could also use 100+ calls per day to reach the 1000 calls a week.
