user2995: I've seen in more than one Blockchain API provider's specs where the transaction inputs and outputs are in the following format:
addresses: ARRAY
The address (or addresses in the case of multi-sig) to which the value was transferred.

I'm confused about the array. When I try these APIs with a transaction where one of the outputs is to a multi sig address, I still see a single multi-sig address in the output.
In which cases would I see multiple addresses in a single output or input?
This the same in these api providers:
https://chain.com/docs#object-bitcoin-transaction
http://dev.blockcypher.com/#transactions
https://toshi.io/docs/#get-transaction

user2995: The answer here is escrow outputs.
When one of the outputs is sent to escrow, the related addresses are listed in those arrays.
Here is an example: https://insight.bitpay.com/api/tx/09dd94f2c85262173da87a745a459007bb1eed6eeb6bfa238a0cd91a16cf7790
A single output will be displayed to have multiple addresses.
Blockcypher's API will show an address starting with 4 instead of multiple adresses. And output script type = pay-to-multi-pubkey-hash
{
      "value": 10860,
      "script": "5121032487c2a32f7c8d57d2a93906a6457afd00697925b0e6e145d89af6d3bca330162102308673d16987eaa010e540901cc6fe3695e758c19f46ce604e174dac315e685a52ae",
      "addresses": [
        "4bkHBecr4EQvVUa8Lsa2kH6rGtvsC9AZ5Y"
      ],
      "script_type": "pay-to-multi-pubkey-hash"
    },


2995: <p>I've seen in more than one Blockchain API provider's specs where the transaction inputs and outputs are in the following format:</p>

<pre><code>addresses: ARRAY
The address (or addresses in the case of multi-sig) to which the value was transferred.
</code></pre>

<p>I'm confused about the array. When I try these APIs with a transaction where one of the outputs is to a multi sig address, I still see a single multi-sig address in the output.</p>

<p>In which cases would I see multiple addresses in a single output or input?</p>

<p>This the same in these api providers:</p>

<p><a href="https://chain.com/docs#object-bitcoin-transaction" rel="nofollow">https://chain.com/docs#object-bitcoin-transaction</a></p>

<p><a href="http://dev.blockcypher.com/#transactions" rel="nofollow">http://dev.blockcypher.com/#transactions</a></p>

<p><a href="https://toshi.io/docs/#get-transaction" rel="nofollow">https://toshi.io/docs/#get-transaction</a></p>
 2995: <p>The answer here is escrow outputs.</p>

<p>When one of the outputs is sent to escrow, the related addresses are listed in those arrays.</p>

<p>Here is an example: <a href="https://insight.bitpay.com/api/tx/09dd94f2c85262173da87a745a459007bb1eed6eeb6bfa238a0cd91a16cf7790" rel="nofollow">https://insight.bitpay.com/api/tx/09dd94f2c85262173da87a745a459007bb1eed6eeb6bfa238a0cd91a16cf7790</a></p>

<p>A single output will be displayed to have multiple addresses.</p>

<p>Blockcypher's API will show an address starting with 4 instead of multiple adresses. And output script type = pay-to-multi-pubkey-hash</p>

<pre><code>{
      "value": 10860,
      "script": "5121032487c2a32f7c8d57d2a93906a6457afd00697925b0e6e145d89af6d3bca330162102308673d16987eaa010e540901cc6fe3695e758c19f46ce604e174dac315e685a52ae",
      "addresses": [
        "4bkHBecr4EQvVUa8Lsa2kH6rGtvsC9AZ5Y"
      ],
      "script_type": "pay-to-multi-pubkey-hash"
    },
</code></pre>
