Europeana rate limits

[sckott]

From tech folks

All requests for HathiTrust applications and APIs are limited by a throttling system. As with all throttling systems, the algorithm is a bit hard to explain. For Data API:Each request debits your account by one. The maximum debt is 50 requests within a 30 second period. A request that exceeds the maximum debt will return a 503 HTTP response. You also receive 0.5 credits per second. You will continue to receive 503 until enough credits accumulate to drop your debt below 50 within 30 seconds.