<p>You'd have to get creative here.</p>

<p>Step 1) Get unspent outputs. <a href="https://bullpay.com/docs#GetUnspentOutputs" rel="nofollow noreferrer">https://bullpay.com/docs#GetUnspentOutputs</a>
You can build your unspent outputs from multiple wallets. As long as you have the private keys, it can be done. 
Step 2) Build your signed transaction. <a href="https://medium.com/coinmonks/how-to-create-a-raw-bitcoin-transaction-step-by-step-239b888e87f2" rel="nofollow noreferrer">https://medium.com/coinmonks/how-to-create-a-raw-bitcoin-transaction-step-by-step-239b888e87f2</a>
Step 3) Send your signed transaction. <a href="https://bullpay.com/docs#SendTransaction" rel="nofollow noreferrer">https://bullpay.com/docs#SendTransaction</a> or use a node.</p>

<p>The part you'll want to repeat is in step 2. Building out the inputs each using their own private keys. The tricky part here is waiting long enough to have multiple outputs to warrant going through all this. </p>

CC BY-SA 4.0
2018-12-16T19:47:42.613Z
2018-12-16T19:47:42.613Z
cleanmarker
<p>I am new in bitcoin. I am developing a PHP website to let users build their wallet on my website. I want to give every user a wallet. I do not want to give users private keys. I keep private keys, so all their bitcoins owns mine. If everyone wants to spend his/her bitcoins, he/she needs to send a withdrawal request and I will handle it. I want to be able to send user's bitcoin at once with one transaction and one fee. So if I give every user a new address, bitcoins will be a changeed (a little amount in every address). So spending them needs lots of fee. What should I do? I am using blockcypher's API. Is there any other API can help? What senario should I do to achieve all above targets? thanks.</p>

CC BY-SA 3.0
2018-03-11T16:43:40.307Z
Bitcoin shows that a bank is not needed. And you want to be the bank.... Right? Well you have to pay the fees if you store the coins on multiple addresses. You can't do anything else.
hardfork
CC BY-SA 3.0
2018-03-11T17:05:27.960Z
@Alpha : For example in blockchain.info there is a wallet and lots of addresses associated with the wallet. If you pay to one or two of the addresses, bitcoin will be gathered in one place and you can spend them in one transaction. My question is How does blockchain.info do that??
Meysam Valueian
CC BY-SA 3.0
2018-03-13T07:26:58.720Z
Yes, that's possible. You can add multiple UTXO. Almost every wallet supports this, but I can't explain you how it works exactly.
hardfork
<wallet><transaction-fees><blockcypher>
Bitcoin wallet website
Meysam Valueian
# Bitcoin wallet website

(Asked by: username_0 on 2018-03-11)

I am new in bitcoin. I am developing a PHP website to let users build their wallet on my website. I want to give every user a wallet. I do not want to give users private keys. I keep private keys, so all their bitcoins owns mine. If everyone wants to spend his/her bitcoins, he/she needs to send a withdrawal request and I will handle it. I want to be able to send user's bitcoin at once with one transaction and one fee. So if I give every user a new address, bitcoins will be a changeed (a little amount in every address). So spending them needs lots of fee. What should I do? I am using blockcypher's API. Is there any other API can help? What senario should I do to achieve all above targets? thanks.

**Tags:** wallet, transaction-fees, blockcypher

> **Comments:**
> **username_1**: Bitcoin shows that a bank is not needed. And you want to be the bank.... Right? Well you have to pay the fees if you store the coins on multiple addresses. You can't do anything else.  
> **username_0**: @Alpha : For example in blockchain.info there is a wallet and lots of addresses associated with the wallet. If you pay to one or two of the addresses, bitcoin will be gathered in one place and you can spend them in one transaction. My question is How does blockchain.info do that??  
> **username_1**: Yes, that's possible. You can add multiple UTXO. Almost every wallet supports this, but I can't explain you how it works exactly.  

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## 1 answers

### Answer by username_2 on 2018-12-16. Score: 1

You'd have to get creative here.

Step 1) Get unspent outputs. <https://bullpay.com/docs#GetUnspentOutputs>
You can build your unspent outputs from multiple wallets. As long as you have the private keys, it can be done.
Step 2) Build your signed transaction. <https://medium.com/coinmonks/how-to-create-a-raw-bitcoin-transaction-step-by-step-239b888e87f2>
Step 3) Send your signed transaction. <https://bullpay.com/docs#SendTransaction> or use a node.

The part you'll want to repeat is in step 2. Building out the inputs each using their own private keys. The tricky part here is waiting long enough to have multiple outputs to warrant going through all this.


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