Simple script to leverage Gemini's API to place orders at a lower fee (0.350% taker fee, 0.100% maker fee currently), mainly for the purpose of automating dollar-cost-averaging (DCA) on using AWS Lambda.

I will not go into the details of getting this function running on AWS and how to set up DCA.

This script assumes AWS Lambda as runtime (but you can run it locally) but also fetches the API Secret stored as SecureString in AWS Systems Manager Parameter Store.

Alternatively you can just change the script and pass in your key and secret in a different way.

The function takes the following inputs from the event:

• account: API Key without the account- prefix, e.g. 123456789 if Gemini generated the API Key account-123456789
• symbol: The symbol for the order you want to place, I have only tested with BTCUSD and ETHUSD
• fiatAmount: The amount of USD (assuming your base currency is USD) you want to spend
• orderType (optional): taker (default) or maker. Note: maker orders might not get filled so you might have to watch your order logs

To use this script, you'll need to set up an API Key with Gemini. I'd suggest playing with the Sandbox first before trying it on your main account.

But the important thing to know is that you only need a Trading scope for the API Key, which allows the following things:

• Check balances
• Place and cancel orders
• Check the status of orders
• See all active orders

So with a Trading API Key, it is not possible to move funds to another account if your API Secret was compromised. The main thing that could happen is that your balances on Gemini could be checked or orders could be placed or cancelled, but at least nothing could be stolen. So it's not that bad BUT make sure your API Secret is secure! This is the reason why I'm using Parameter Store.

To create the API Key, go to your profile and click API:

Then click CREATE A NEW API KEY:

Select Primary and click CREATE A NEW API KEY:

Optionally set your own name, select Trading as scope, copy your API Secret (ideally also your API Key) in a secure place, click the last checkbox to acknowledge that you copied it and hit CONFIRM:

You've successfully created your API Key, you're now ready to go!

You can also run the script locally by passing a few environment variables:

• LOCAL: Set this to true if you're running locally
• ACCOUNT: API Key without the account- prefix, e.g. 123456789 if Gemini generated the API Key account-123456789
• SYMBOL: The symbol for the order you want to place, I have only tested with BTCUSD and ETHUSD
• FIAT_AMOUNT: The amount of USD (assuming your base currency is USD) you want to spend
• ORDER_TYPE (optional): taker (default) or maker. Note: maker orders might not get filled so you might have to watch your order logs
• SANDBOX (optional): Set to true to run this script against the Gemini Sandbox, i.e. a testing account (that you need to sign up for) rather than a real account
• AWS_PROFILE (optional): Set to the name of your alternative AWS profile defined in ~/.aws/credentials if you're not using the default profile

So running locally would be something like:

SANDBOX=true ACCOUNT=123456789 LOCAL=true FIAT_AMOUNT=10 SYMBOL=BTCUSD ORDER_TYPE=taker node index.js