Rate Limiting for APIs | Dataford Interview Questions

Explain how you would implement rate limiting in an API.

Implement a function that processes requests in chronological order and decides whether each request is allowed. Use a per-client sliding window: a request is allowed when fewer than limit previously accepted requests from that client occurred within the preceding window seconds.

Return one Boolean per request. The input contains (client_id, timestamp) pairs, timestamps are nondecreasing integers, and only accepted requests count toward the limit.

Constraints

0 <= requests.length <= 10^5
Each request is a pair of a client identifier and an integer timestamp
Timestamps are nondecreasing
1 <= limit <= 10^9
1 <= window <= 10^9
Only accepted requests count toward a client's limit

Function Signature

def rate_limit(requests, limit, window):

Your question is Rate Limiting for APIs. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Explain how you would implement rate limiting in an API.

Return one Boolean per request. The input contains (client_id, timestamp) pairs, timestamps are nondecreasing integers, and only accepted requests count toward the limit.

Constraints

0 <= requests.length <= 10^5
Each request is a pair of a client identifier and an integer timestamp
Timestamps are nondecreasing
1 <= limit <= 10^9
1 <= window <= 10^9
Only accepted requests count toward a client's limit

Function Signature

def rate_limit(requests, limit, window):

Your question is Rate Limiting for APIs. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.