user124345: We're looking into making website for trading Bitcoin.
Users get individual bitcoin addresses to deposit BTC.
How do we avoid paying transaction fees for every of these deposit transactions that we'll have to 'repeat' to send money to our 'system' wallet address?
We've played with bitcoind json-rpc. Could blockchain.com API help in aggregating this deposition payments without fees?
Thank you

user5406: Every output of a transaction needs to be explicitly spent as an input eventually, but there is no need to stage deposits separately and resend them to yourself again. Maybe I'm missing something, but you could and should give out addresses of your service's wallet to your users and thus get deposits directly into your wallet. If you give each user a new address for every deposit, you can tell via the funded address which user to credit, and the funds will immediately be available to process withdrawals.
If your wallet grows too large, you'll want to consolidate some funds either back into the hot wallet or move some into cold wallet with stricter security policies.
You may find my blog post on UTXO management for enterprise wallets interesting.

124345: <p>We're looking into making website for trading Bitcoin.</p>
<p>Users get <em>individual bitcoin addresses</em> to deposit BTC.</p>
<p>How do we avoid paying transaction fees for every of these deposit transactions that we'll have to 'repeat' to send money to our 'system' wallet address?</p>
<p>We've played with <strong>bitcoind</strong> json-rpc. Could <strong>blockchain.com API</strong> help in aggregating this deposition payments without fees?</p>
<p>Thank you</p>
 5406: <p>Every output of a transaction needs to be explicitly spent as an input eventually, but there is no need to stage deposits separately and resend them to yourself again. Maybe I'm missing something, but you could and should give out addresses of your service's wallet to your users and thus get deposits directly into your wallet. If you give each user a new address for every deposit, you can tell via the funded address which user to credit, and the funds will immediately be available to process withdrawals.</p>
<p>If your wallet grows too large, you'll want to consolidate some funds either back into the hot wallet or move some into cold wallet with stricter security policies.</p>
<p>You may find my blog post on <a href="https://blog.bitgo.com/utxo-management-for-enterprise-wallets-5357dad08dd1" rel="nofollow noreferrer">UTXO management for enterprise wallets</a> interesting.</p>
