Is there any way to check for this data in blockchain?

I want to search this value: 554e6963444320 and want to return this transaction https://blockchain.info/tx/7e92e90f221ad28daf42b5b8bda4c8e244e37af48527fcd12b2518db5d3315bd

  • 1
    This will require parsing the blockchain and looking for your data string to match transaction(s) which contain that data. Building an index of all op_return transactions could speed this greatly, but to my knowledge it is not yet available as a service or product.
    – Scrybe
    Commented Mar 15, 2015 at 16:58
  • How to identify transactions with op_return? Commented Mar 15, 2015 at 17:17

3 Answers 3


The Chain.com API offers functionality for returning OP_RETURN data by:

  1. Address
  2. TxID
  3. Block height

The JSON return data from the REST API has a text field which is meant to be the decoded hex data sent (ie 6a``hex data) but it's returned in the format \\x``hex data.

In Python you can simply do this:

import __future__
import requests; from binascii import unhexlify
rdata = requests.get("https://api.chain.com/v2/bitcoin/addresses/%s/op-returns?api-key-id=DEMO-4a5e1e4" % "1Bj5UVzWQ84iBCUiy5eQ1NEfWfJ4a3yKG1") # substitute URL here
assert rdata.status_code == 200
jdata = rdata.json()
hexdata = [unhexlify(str(t["text"]).encode("utf-8"))) for t in jdata
  • How would I do a search in the bitcoin core? Commented Mar 16, 2015 at 13:51
  • 1
    api.chain.com doesn't work anymore
    – mixdev
    Commented Jun 15, 2017 at 7:24

This Blockchain explorer: https://blockchair.com/ allows you to search for embedded data in 19 different Blockchains. And on this URL https://bitcoinstrings.com/all I think you can get all embedded texts.


You can do it via https://www.smartbit.com.au/ that already parses all the data including op_returns

  • 2
    It's now offline Commented Apr 12, 2022 at 15:38

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