Author: StJohn Piano
This page is subject to change at any time. It is not signed by its author or by Edgecase Datafeed.
508 words - 207 lines - 6 pages


For buying bitcoin:

For observing current fee rates of transactions:
It displays estimated delays (in blocks and in minutes) for ranges of fee rates (in satoshi / byte).

For searching the Bitcoin blockchain:
Inputs: address, transaction hash (txid), block hash, block number.
Note: On a transaction page e.g.
it's possible to click Advanced Details / API Call, which produces a raw text dump of the transaction, e.g.

To look up the list of unspent outputs in an address, use:
- "tx_hash_big_endian" is the txid.
- "tx_output_n" is the previous output index.

An address page e.g.
shows the current balance, the list of previous transactions (and their txids), the outputs sent by these transactions to the address, the spent/unspent status of these outputs, and the value of each output.

For tracking the status of a transaction (i.e. whether it has been mined or not), you can search for its txid using the search field on
If the transaction has been received by the service but has not yet been mined, it will be displayed with "Confirmations: 0/6".
If the service has not seen the transaction, you will get a search result similar to this:
"No transaction found with the hash
You can refresh the page to re-check a transaction's status.

For decoding a signed transaction:
If the service can successfully decode a transaction, this indicates that the transaction is formatted correctly.

For broadcasting a signed transaction to the Bitcoin network:

For looking up the raw hex form of a transaction:

For extracting text from PDF files:
1) ocr.space
2) www.ocrconvert.com

Duplicate / less convenient services:

It's possible to read through a transaction raw text dump in order to find the index of a particular unspent output. An output in the output list is implicitly 0-indexed (the first one has index = 0).

Example transaction raw text dump:

Procedure for finding the output index of a particular unspent output in the JSON-formatted raw transaction information (for use when making a transaction that spends this output):
1) Copy the transaction data into a text editor. Delete everything apart from the output list. Count all '{'. Result is an integer e.g. 35.
2) Find the unspent output by searching for the source address. Select the text of all outputs that appear after it. Delete this text.
3) Count all '{'. Result is an integer e.g. 13.
4) The result of step (3) gives you the position of the unspent output in the output list e.g. it's the 13th output. Taking the initial index to be 0, the output's index would then be 12.


Author: Ken Shirriff
Important articles:
- Bitcoins the hard way: Using the raw Bitcoin protocol
- Bitcoin mining the hard way: the algorithms, protocols, and bytes