To use API calls on blockr.io all you have to do is point your API calls to tbtc.blockr.io domain.

• For example, API call for mainnet is:
  http://btc.blockr.io/api/v1/address/info/18JsTGxcqTg4uoXMCftgCQa6dG3kywtQme

• and API call for testnet would be:
   http://tbtc.blockr.io/api/v1/address/info/mpRZxxp5FtmQipEWJPa1NY9FmPsva3exUd

(tbtc.blockr.io instead of btc.blockr.io)


http://blockr.info/images/testnet/BTCtestnet-banner.jpg