Input: any old Bitcoin address e.g.


Output: the FirstBits, in this case 1BCN1u

  • can you please tell where I can read about old and new bitcoin addresses? – Salvador Dali Oct 18 '13 at 23:49
  • @SalvadorDali - I don't understand what you mean "old and new addresses" – ripper234 Oct 19 '13 at 14:31

Blockchain.info has APIs to generate and resolve firstbits.

Get firstbits,


Get address,




| improve this answer | |
  • What is the purpose of this? – bvpx Oct 18 '13 at 14:58
  • 1
    @bvpx: Https://en.bitcoin.it/wiki/Firstbits tells us that firstbits are basically a way for bitcoin users to type a few less key strokes (an address shortner for bitcoin addresses). However there are more than a few downsides to it. I hope the information is helpful.n Just start at the beginning and learn everything bitcoin wiki touches on. Feel reese to ask more questions. I always suggest using the search engine before posting so you keep good rep. You can always privately message me. But I am over on my altcoins pool mostly. – Joe White Oct 18 '13 at 15:22
  • 2
    This service seems to be out of order currently. – akaihola Apr 22 '14 at 5:25

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:



Hope this helps :)

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.