Input: any old Bitcoin address e.g.
1BCNEPySL4gzzjg8NNyNsQYJWYmZwpgaPF
Output: the FirstBits, in this case 1BCN1u
Input: any old Bitcoin address e.g.
1BCNEPySL4gzzjg8NNyNsQYJWYmZwpgaPF
Output: the FirstBits, in this case 1BCN1u
Blockchain.info has APIs to generate and resolve firstbits.
Get firstbits,
http://blockchain.info/q/getfirstbits/1BCNEPySL4gzzjg8NNyNsQYJWYmZwpgaPF
Get address,
http://blockchain.info/q/resolvefirstbits/1paypal
Having seen that yes blockchain.info no longer offers this service I was able to find only one other Block explorer that do offer the FirstBit lookup on addresses:
https://www.walletexplorer.com
https://www.walletexplorer.com/address/1BCN1ugdKdWd9pQ8Am9hMhtHZfmbXzxE8a?from_firstbits=1BCN1u
Hope this helps :)