bitcoind json-rpc requests per second I'm starting up a new bitcoin based commerce site and am wondering how many transactions per second the bitcoin JSON-RPC API can accept? A user can have an account balance in bitcoin and I was initially thinking of storing all transactions in a database and then querying that to determine their account balance, but after reading up on blockchain reorgs and whatnot decided against it. 

So is it feasible to just use the bitcoin API directly, or should I implement some sort of caching/load balancing?
Benchmark it and see, although be aware that bitcoind has never been optimized for handling thousands of accounts with hundreds of thousands of transactions. In particular, calls like 'getbalance' get slower the more transactions that are in the wallet.

Happily, there are now other implementations that claim to be better at handling lots of accounts/wallets/transactions.