optimal-buy-gdax

Scheduled buying of BTC, ETH, and LTC from GDAX optimally! Be your own index/hedge fund, and stop paying those greasy management fees.

What is this?

This is a Python script you can use to automatically buy Bitcoin, Ethereum, and Litecoin using the GDAX API. It buys these 3 currencies, weighted by market cap (as reported by coinmarketcap.com), using a form of dollar cost averaging. according to the following logic:

Check current balances of USD, BTC, ETH, and LTC
If the USD balance is above $100, buy BTC, ETH, and LTC weighted by market cap
If there's enough USD available, place 5 discounted limit orders at the current price minus 0.5% up to 4.5%, each order with 1/5th of the remaining amount to buy for each coin(see "Details on the orders placed", below)
If there isn't enough USD available, place 1 buy order at 0.5% off the current price
If the USD account balance is below $100, withdraw coins to desired addresses

You can also use the same script to schedule deposits from your bank account periodically, such as when you're paid.

Ideally, this script would help to make sure that when we dip—

we buy.

USE AT OWN RISK

Duh. Not my fault if you lose everything.

Unless you place absolute trust in me, some guy from the Internet, I suggest you clone the repo and build your own container to protect yourself from any sort of funny business.

How do I use it?

Get yourself a hardware wallet, such as a Ledger or TREZOR.
Set up a GDAX account, and link your bank account
Create the necessary API credentials for GDAX, with permissions to manage funds, withdraw without 2FA, and trade
Determine the payment_method_id value by using the GDAX API (you can use your browser's developer toolbar, here's a quick video showing how)
Get a machine somewhere (GCE, EC2, Digital Ocean) with Docker and systemd

Copy systemd files over:

 $ sudo cp optimal-buy-gdax-*.{service,timer} /etc/systemd/system

Edit /etc/systemd/system/optimal-buy-gdax-buy.service, /etc/systemd/system/optimal-buy-gdax-buy.timer, /etc/systemd/system/optimal-buy-gdax-deposit.service, and /etc/systemd/system/optimal-buy-gdax-deposit.timer to your liking. Make sure you:
- Change the BTC, ETH, and LTC deposit addresses to deposit the coins into your wallet (use a Ledger or TREZOR)
- Put the correct API keys in
- Check the deposit amount (start with something small, like $150, to make sure it actually works first)
- Check the timer dates (it would be sensible to change the hh:mm so your script doesn't run the same time as everyone else's)

Enable the systemd units:

 $ sudo systemctl enable optimal-buy-gdax-buy.service
 $ sudo systemctl enable optimal-buy-gdax-buy.timer
 $ sudo systemctl enable optimal-buy-gdax-deposit.service
 $ sudo systemctl enable optimal-buy-gdax-deposit.timer

Start the systemd timers: $ sudo systemctl start optimal-buy-gdax-buy.timer $ sudo systemctl start optimal-buy-gdax-deposit.timer
Enjoy!

Configuration

usage: optimal-buy-gdax.py [-h] --mode MODE [--amount AMOUNT] --key KEY
                           --b64secret B64SECRET --passphrase PASSPHRASE
                           [--api-url API_URL]
                           [--payment-method-id PAYMENT_METHOD_ID]
                           [--btc-addr BTC_ADDR] [--eth-addr ETH_ADDR]
                           [--ltc-addr LTC_ADDR]
                           [--starting-discount STARTING_DISCOUNT]
                           [--discount-step DISCOUNT_STEP]
                           [--order-count ORDER_COUNT]

Buy coins!

optional arguments:
  -h, --help            show this help message and exit
  --mode MODE           mode (deposit or buy)
  --amount AMOUNT       amount to deposit
  --key KEY             API key
  --b64secret B64SECRET
                        API secret
  --passphrase PASSPHRASE
                        API passphrase
  --api-url API_URL     API URL (default: https://api.gdax.com)
  --payment-method-id PAYMENT_METHOD_ID
                        Payment method ID for USD deposit
  --btc-addr BTC_ADDR   BTC withdrawal address
  --eth-addr ETH_ADDR   ETH withdrawal address
  --ltc-addr LTC_ADDR   LTC withdrawal address
  --starting-discount STARTING_DISCOUNT
                        starting discount (default: 0.005)
  --discount-step DISCOUNT_STEP
                        discount step between orders (default: 0.01)
  --order-count ORDER_COUNT
                        number of orders (default: 5)

Details on the orders placed

By default, there are 5 orders placed (for each currency) in steps of 1%, starting at a 0.5% discount from the current price. To illustrate, if the current price was $100 (per LTC, let's say), and you had $100 to buy, the orders would look like this:

Order	Size	Price
1	0.2010 LTC	$99.5
2	0.2030 LTC	$98.5
3	0.2051 LTC	$97.5
4	0.2072 LTC	$96.5
5	0.2094 LTC	$95.5

Furthermore, the amount of each currency to buy will be based on the current market cap weighting of each coin. For example, at the time of writing the weights are:

Coin	Market Cap (USD)	Weight
BTC	$195,824,365,435	0.791
ETH	$46,080,472,372	0.186
LTC	$5,592,776,540	0.023

So if your USD account had $1000 to invest, the amount invested in each would become:

Coin	Weight	Amount Invested
BTC	0.791	$791
ETH	0.186	$186
LTC	0.023	$23

Caveats/limitations

Currently it only supports USD
Some values are hardcoded, but if you want to change that feel free to send a PR!
If you try to trade manually or using some other bot at the same time, you're probably going to have a bad time
You might have a few dollars (<$100) sitting in your account at all times, even when all orders have been filled
It makes a best effort with minimal complexity to invest all of your USD, but it may not be possible to fill all orders right away
It may take a few days for the market to drop enough for the buys to fill

Tip jar

If you got some value out of this, please send some kudos my way:

BTC: 3EEAE1oKEMnmHGU5Qxibv9mBQyNnes8j8N
LTC: 3MxmLzTf4sPsFBGYUnX9MMMbTMeaUSox46

pri8771 / optimal-buy-gdax