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Arcadia's Spike Limiter go-live date is scheduled for Monday, August 18th, 2025. Please review and adjust your workflows if & as needed ahead of time to minimize disruptions to your implementation.

Overview

To ensure fair access and high performance for all users, our Signal and Switch APIs now includes a dynamic spike limiter. This system protects against sudden, uncharacteristic surges in API traffic that could degrade service for others. The spike limiter works alongside existing rate limiting best practices, including concurrency controls and gradual ramp-up of request rates.

How the Spike Limiter Works

• Dynamic Limits: The system calculates a unique requests-per-minute (RPM) limit for your organization based on your own recent usage patterns. It looks at your 60-minute rolling average traffic and also considers your traffic's variability to distinguish between normal fluctuations and genuine spikes.
• Real-Time Enforcement: When your request rate exceeds this dynamic limit, the API will respond with an HTTP 429 (Too Many Requests) error. The response will include a Retry-After header indicating when you can safely retry.
• Rolling Window: The spike limiter uses a rolling 60-minute window to determine your average and variability, recalculating limits every minute.

What to Do If You Receive HTTP 429

1. Pause and retry: Follow the Retry-After header if present, or introduce a delay before retrying
2. Review Your workflow: Ensure you are following the best practices outlined in our Rate Limiting Suggestions, such as using appropriate concurrency and gradually ramping up your request rates
3. Monitor: If you continue to experience throttling, review your traffic patterns to identify any unexpected spikes or irregularities, and adjust accordingly

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Rate Limit Best Practices

Summary

• Adhere to concurrency and ramp-up best practices
• Monitor your API usage and system performance
• The spike limiter is designed to protect all customers and ensure fair access
• If you have questions about optimizing your workflow, contact support for guidance