Non deterministic and inconsistent rate limit of 10 orders/sec

explorer

I trade large quantities and have been using API for couple of years now to place 40+ orders at any given point in time. Since last 4-6 months, I have started observing rate limit errors for order placement API. I implemented client side throttling 2 years ago where max 9 orders are placed per second with gap of 1 second between bursts. The implementation never resulted in "Maximum allowed order requests per second exceeded" errors in year 2025.

Interestingly, around May 2026 I started receiving many failures everyday due to too many order requests error. Observing that, I changed the throttling config to place 8 orders/second and then 6 orders/second. Changing from 8 to 6 orders per window reduced error rate but it was never zero.

Here is how the throttler works:
1. Accept all orders
2. Place 6 orders in burst
3. Wait 1 second
4. Place next 6 orders

Then I did few more experiments to understand rate limiter but with no complete success. The only way I was able to submit multiple order bursts was by increasing the window size to 1800ms and dropping orders per window to merely 7, down from 10. Following is one such log where 7 orders are placed every 1250ms. As you can see, first burst(1-7) was placed by 24.194 and the next burst (8-14) was placed after 1.2s at 25.439. This should have resulted in all successes. However, requests 13 and 14 failed. There is no explanation why requests 13, 14 failed despite being submitted after 1 second than the previous burst.

Timestamps in hh:mm:ss.SSS format.

7 orders per window, 1250ms window size

14:35:24.187 sending request number 1
14:35:24.191 sending request number 2
14:35:24.191 sending request number 3
14:35:24.192 sending request number 4
14:35:24.193 sending request number 5
14:35:24.193 sending request number 6
14:35:24.194 sending request number 7

14:35:24.341 request number 1 placed successfully
14:35:24.342 request number 2 placed successfully
14:35:24.351 request number 7 placed successfully
14:35:24.353 request number 4 placed successfully
14:35:24.387 request number 5 placed successfully
14:35:24.389 request number 3 placed successfully
14:35:24.395 request number 6 placed successfully

14:35:25.439 sending request number 8 (2nd burst after 1st burst was accepted and placed successfully)
14:35:25.440 sending request number 9
14:35:25.442 sending request number 10
14:35:25.443 sending request number 11
14:35:25.444 sending request number 12
14:35:25.444 sending request number 13
14:35:25.445 sending request number 14

14:35:25.466 request number 13 failed due to too many requests error
14:35:25.467 request number 14 failed due to too many requests error
14:35:25.467 request number 9 placed successfully
14:35:25.468 request number 10 placed successfully
14:35:25.469 request number 8 placed successfully
14:35:25.470 request number 12 placed successfully
14:35:25.470 request number 11 failed due to too many requests error

14:35:26.690 sending request number 15 (third burst)
14:35:26.718 request number 15 placed successfully

My observations suggest that rate limiter is not using known rate limiter algo viz. sliding window, sliding window log/counter, leaky/token bucket.

It would be very helpful if Kite team clarifies:
1. What algorithm is used for API/orders rate limiting?
2. What is the configuration for the algorithm?
3. The reason I am seeing inconsistent API responses?
4. What changed in 2026 vs 2025 that has suddenly caused order rejection considering no client changes.

Thank you for reading!