Some API calls are available with CORS headers if you add a cors=true paramter to the request

Please limit your queries to a maxmimum of 1 every 10 seconds. All bitcoin values are in Satoshi i.e. divide by 100000000 to get the amount in BTC

Realtime

Address Lookups

To filter by x number of confirmations include the confirmations parameter

e.g. /q/addressbalance/1EzwoHtiXB4iFwedPr49iywjZn2nnekhoj?confirmations=6
to only include transactions with 6 or more confirmations. This is extremely important if you are processing valuable transactions.

Transaction Lookups

Normalized Hash Lookups

A Normalized Transaction Hash is a hash of the serialized transaction with it's input scripts blank. This hash cannot be altered through transaction malleability

Tools

Misc

Firstbits