I have a question about mirroring trades as suggested in the blog entry. I guess mirroring is all done in numbers (profit/loss percentage) but not in real transactions since we won't have any secret keys to make trades for our followers, just like a sort of fantasy trading. Of course it can be done if we create accounts for our users and we manage them but then managing other people's money is always risky and hacks can be disastrous. So, should we go with fantasy trading only? The trader will make live transactions but followers will only reflect numbers on the DB, not real trades, right?

You can give your users the ability to enter their private key, like https://stellarterm.com/#account does. It stays on client side and it is not accessible to them. Once the transaction is signed on the client side it travels encrypted. You do not have to create users accounts, users with existing private keys should be able to use them to "login" to your website, at least that is how I am implementing it. My issue is that once a user wants to mimic another trader but he is not online once the trade happens, how his private key is going to be fetched so that he can sign a similar transaction at the same time ?

strasse86 "once a user wants to mimic another trader but he is not online once the trade happens, how his private key is going to be fetched so that he can sign a similar transaction at the same time ?" That's exactly the point of the question. We don't have the keys to mirror the operations as they happen so it's useless unless we do some fantasy trading or create accounts for them, again risking their money. I'll start playing with fantasy trading and then implement something else as we advance.

Sounds like you'd need to take a federation approach https://www.stellar.org/developers/guides/anchor/index.html

Or just have a rebalance button when a user logs back in to the app

Actually, just use multisig and have the user add your base account as a signer: https://www.stellar.org/developers/guides/concepts/multi-sig.html

Ok here is the first draft, this is all fake data just to see how everything fits in place. I have a fixation with dark themes but will offer also a light option just in case. Feedback highly appreciated.

mikeyrf That sounds like an interesting option. Right now deciding if the user will add us or we issue a new account with both signers at once, the latter being easier on new users and will allow to track it better since no other transactions will be submitted without both signatures.

Yea I’ll likely be implementing the latter

I'm assuming that trade mirroring has to be automated, i.e. without user intervention? Then multisig would have to be 2/1. Not sure how helpful that would be. Also (down the line) there will probably be compliance issues with taking custody of the account key. Just look at all the KYC processes Satoshipay is doing- and they're not even custodial.

Is there a way to atomically get the balance and the last transaction? If not seems like there would always be a race condition when trying to see the balance associated with a transaction.

SBC - Social trading questions

Torkus

Now, if you trade your XYZ for BTC with a profit of 10% then BTC tanks and loses -15% then you sell all and buy ETH and it gains 25% then your current ROI is 20% of which -5% are in stone (10% and -15% closed positions) and ETH subject to change recalculated by crons until you close it back to XLM or make another trade. In other words, the open positions are the ones that fluctuate. Open positions are considered all assets you hold greater than zero. We should consider XLM as the quote asset or currency, so the fluctuations in XLM don't affect your ROI but all other assets do.

mikeyrf

Torkus I’d use USD as the reference point, like StellarTerm does

mikeyrf

Torkus No, your ROI would be 75% in that case.

Torkus

mikeyrf Exactly so ROI for a time period is equal to the sum of profit/loss in all trades (they must be recorded one by one) and the sum of all open positions (profit at current price of all assets held).

ROI = ∑P + ∑O

mikeyrf

You’re likely better off not storing data about each transaction in your db (there will be many) and simply doing the more general cron job each day of portfolio value.

Yes the rankings will be skewed when a user deposits funds, but that’s incentive to have more people associating accounts with your platform anyway. Probably better dealing with that than dealing with significant # of tx records

Torkus

It will get even messier if the trader buys 100 XYZ then dumps 50 at one price, then 30, then 20 at different prices, or if mixing more buys and sells in different amounts and prices so we'll have to calc weighted averages.

mikeyrf

Why? I’m missing your point. 24 h cron job to record portfolio value each day would cover that easily

Torkus

Ok take these txs as an example then we can compare results:

Starting balance 100 XLM
Buy 20 XYZ at 1.00
Buy 40 XYZ at 1.20
Deposit 200 XLM
Sell 50 XYZ at 1.10
Sell 10 XYZ at 0.90
Withdraw 150 XLM
Buy 100 XYZ at 0.75
Price of XYZ at closing 1.05 (cron job)

ROI? (Profit/loss by tx and total ROI)

mikeyrf

I get it. That’s not my point. I’m saying people care more about how much they’re worth than how much profit they’ve made solely on trading.

So if someone pays my account 100 XLM for services rendered in the real world, I’m happy counting that toward their % portfolio increase on the platform over time.

Yes I understand this is not exactly what is being asked for in the challenge details for social trading, but i don’t see it as an unreasonable deviation

Torkus

I know that's premature optimization, we should have something viable working first and from there iterate making it better adding more features as needed. Ok, let's keep on coding now.

mikeyrf

True true

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