How to get the largest bitcoin transactions with Blockchair's API

What is Blockchair?

Today, we use blockchain explorers everyday in order to track our transactions or extract some stats about cryptocurrencies. Blockchair is the most advanced search engine for exploring 17 blockchains (and more in the future).

Blockchair keeps your personnal data secret and has a "Crypto-anarchist corner" allowing to use Blockchair through the Tor Browser for example. They aspire to become the DuckDuckGo for the blockchain community and act for the adoption of this technology.

It is for all these reasons that we decided to work with Blockchair.

Blockchair's API ❤️

Blockchair's API represents 40% of our data, mainly for bitcoin, ethereum and ERC 20 tokens.

But today we will focus on bitcoin and we will see how to index the biggest bitcoin transactions.

Api requirements, pricing and rate limit.

As you can see in the official documentation, you can use Blockchair API for free if you don't need a lot of charge (Up to 1440 requests a day for the Free Plan).

If you need more calls, consult Blockchair Plans here.

If you are a student, you can use your GitHub student account to get premium access for Blockchair's API ✌🏼✌🏼.

Have you made your choice? Let's see how to use the API

As a first step, it is important to keep the documentation open in order to understand everything. We're just going to focus on the infinitable endpoints (SQL-like queries) for the transactions part.

This endpoint will allow us to make requests with conditions to find bitcoin transactions.

Our first request

# Transactions endpoint
GET https://api.blockchair.com/{:btc_chain}/transactions?{:query}

Remember the goal, here we want to recover bitcoin transactions with a total output value greater than $1,000,000. For that, we will replace {:btc_chain} by bitcoin and we will construct our query logic like this: q=output_total_usd(1000000..).

Which gives that:

GET https://api.blockchair.com/bitcoin/transactions?q=output_total_usd(1000000..)

If you run this request in Postman for example, you will get this result:

{
    "data": [
        {
            "block_id": 656595,
            "id": 586132324,
            "hash": "5efb8d3b2e67fb7984872bff49103fe59419a068cb0b9fec3c0196d699715a7a",
            "date": "2020-11-12",
            "time": "2020-11-12 14:37:46",
            "size": 3003,
            "weight": 9729,
            "version": 1,
            "lock_time": 656594,
            "is_coinbase": false,
            "has_witness": true,
            "input_count": 3,
            "output_count": 61,
            "input_total": 25000841362,
            "input_total_usd": 3923410,
            "output_total": 25000619406,
            "output_total_usd": 3923370,
            "fee": 221956,
            "fee_usd": 34.8318,
            "fee_per_kb": 73911.4,
            "fee_per_kb_usd": 11.599,
            "fee_per_kwu": 22813.9,
            "fee_per_kwu_usd": 3.5802,
            "cdd_total": 22.899962184847
        },
        ...
    ],
    "context": {
        "code": 200,
        "source": "A+T",
        "limit": 1,
        "offset": 0,
        "rows": 1,
        "pre_rows": 1,
        "total_rows": 2065884,
        "state": 656595,
        "cache": {
            "live": true,
            "duration": 60,
            "since": "2020-11-12 14:54:27",
            "until": "2020-11-12 14:55:27",
            "time": null
        },
        "api": {
            "version": "2.0.68",
            "last_major_update": "2020-07-19 00:00:00",
            "next_major_update": null,
            "documentation": "https://blockchair.com/api/docs",
            "notice": "Beginning July 19th, 2020 we start enforcing request cost formulas, see the changelog for details"
        },
        "time": 2.0017759799957275,
        "render_time": 0.01679706573486328,
        "full_time": 2.018573045730591,
        "request_cost": 1
    }
}

data contains an array of database rows. Each row is in the following format:

Column	Type	Description
block_id	int	The height (id) of the block containing the transaction
id	int	Internal Blockchair transaction id (not related to the blockchain, used for internal purposes)
hash	string [0-9a-f]{64}	Transaction hash
date	string YYYY-MM-DD	The date of the block containing the transaction (UTC)
time	string YYYY-MM-DD HH:ii:ss	Timestamp of the block containing the transaction (UTC)
size	int	Transaction size in bytes
weight †	int	Weight of transaction in weight units
version	int	Transaction version field
lock_time	int	Lock time — can be either a block height, or a unix timestamp
is_coinbase	boolean	Is it a coinbase (generating new coins) transaction? (For such a transaction input_count is equal to 1 and means there's a synthetic coinbase input)
has_witness †	boolean	Is there a witness part in the transaction (using SegWit)?
input_count	int	Number of inputs
output_count	int	Number of outputs
input_total	int	Input value in satoshi
input_total_usd	float	Input value in USD
output_total	int	Output value in satoshi
output_total_usd	float	Total output value in USD
fee	int	Fee in satoshi
fee_usd	float	Fee in USD
fee_per_kb	float	Fee per kilobyte (1000 bytes) of data in satoshi
fee_per_kb_usd	float	Fee for kilobyte of data in USD
fee_per_kwu †	float	Fee for 1000 weight units of data in satoshi
fee_per_kwu_usd †	float	Fee for 1000 weight units of data in USD
cdd_total	float	The number of destroyed coindays

More info about data fields here

Now, we want to adjust our request in order to have transactions, with output total value greater than $1,000,000, and total output wich is equal to 1 and let it be ordered on the time field in the ASC order.

GET https://api.blockchair.com/bitcoin/transactions?q=output_total_usd(1000000..),output_count(1)&limit=1&s=time(asc)

I'll let you try 😉

To conclude

We only reviewed a tiny fraction of what Blockchair's API is able to do, I will let you make your proposed opinion. Be curious, and consult the official documentation for more information.

Disclaimer: This article is for informational purposes only and you should not construe any such information as investment or other advise. ClankApp services do not engage in any trading activities. We urge everyone to do their own research and draw their own conclusions.