nrml
PerformancePro problem

Fix the Multi-Tenant Rate Limiter

Preserve fractional refill credits while isolating client quotas.

The scenario

Preserve fractional refill credits while isolating client quotas.

A failure to reason about

A client making evenly spaced requests loses fractional refill credits, while another client’s activity unexpectedly affects its quota.

Illustrative context for the topic. The exercise’s full requirements arrive in the workspace.

Questions to bring to your review

  • Which caller makes the reported behavior visible?
  • What focused regression would distinguish the current behavior from the requirement?
  • What existing behavior must remain intact after the change?

Skills you will practice

  • Rate limiting
  • Time arithmetic
  • Isolation

Read the existing code, reproduce the reported behavior, review proposed changes, and verify your final implementation. You can use AI assistance while staying responsible for the result.

Prepare with a worked example

See how nrml evaluates an attempt, including the limits of automated evidence.