if there is rate limitation

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Yes, Mixpanel does have rate limitations that can cause some events to be processed while others are dropped. This inconsistent event processing can happen for several reasons:

Mixpanel enforces rate limits to ensure system integrity and prevent any single project from monopolizing resources:

- Ingestion API: Limited to 2GB of uncompressed JSON per minute or approximately 30,000 events per second, measured on a rolling 1-minute basis Rate Limits

When you exceed these limits, Mixpanel returns a 429 status code ("Too Many Requests"), and those events won't be processed until you're back under the limit.

To deal with rate limits effectively, Mixpanel recommends:

1. Send data with concurrent clients (10-20 clients sending 2K events per batch works best) 2. When you receive 429 errors, implement an exponential backoff strategy with jitter 3. Use gzip compression to reduce network usage 4. Don't retry validation errors (400 status code) as they will consistently fail and count toward your rate limit 5. For 502 or 503 errors, use the same backoff strategy as with 429s

Import Events

Another reason some events might not be processed is Mixpanel's hot shard protection. If a single distinct_id sends more than 200,000 events per day, Mixpanel will transform those events to protect system performance:

- The event name will be changed to $hotshard_events - The distinct_id will be changed to an empty string - Original values are preserved in properties

Hot Shard Limits

- Event validation failures: Events that fail validation (e.g., exceeding size limits) will be rejected - Historical data limitations: The /track endpoint only accepts events from the last 5 days Track Events - Size limits: Each event must be smaller than 1MB of uncompressed JSON and have fewer than 255 properties

If you're experiencing inconsistent event processing, I recommend implementing proper error handling with backoff strategies and monitoring your API responses for 429 status codes.

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