Square API keys
Square API credentials belong in configuration, not in a commit. This page covers where to create one, what it looks like, and how APIKeyConnect stores it without ever being able to read it.
The facts
- Category
- Payment & Financial
- API host
connect.squareup.com- Key format
EAAAE.xxxxxxxxxxxxxxxxxxxxxxxxxxxx- Env variable
SQUARE- Sensitivity
- Critical
- Create a key
- https://developer.squareup.com/apps — Open or create an application, then click Credentials in the left nav for the production access token.
- Documentation
- https://developer.squareup.com/reference/square
A leaked key here can move money, delete data, or impersonate your organisation. Rotate immediately if one is ever exposed, and never let one reach a client bundle.
Kinds of Square key
Access Token
How APIKeyConnect stores it
The key is encrypted in your browser with AES-256-GCM, under a key derived from your master password with PBKDF2-SHA-256 at 600,000 iterations. The password never leaves your device, and the server holds ciphertext it has no way to open.
What the server can see — and what this design does not protect against — is written out in full on the security page. That section exists because a page with no limits section is marketing.
Questions
Where do I get a Square API key?
Square issues keys from https://developer.squareup.com/apps. Open or create an application, then click Credentials in the left nav for the production access token. Once you have it, store it in APIKeyConnect rather than in a .env file you might commit — the key is encrypted on your device with a master password we never receive.
What does a Square API key look like?
Square keys follow the pattern EAAAE.xxxxxxxxxxxxxxxxxxxxxxxxxxxx. Knowing the shape is useful for spotting one that has been pasted into a commit, a log line, or a support ticket — the places keys leak from most often.
What environment variable should I use for Square?
Most projects use SQUARE. APIKeyConnect recognises these names, so importing an existing .env maps the value onto Square automatically instead of leaving it as an unlabelled string, and generating a .env writes it back under the same name.
How dangerous is a leaked Square key?
Critical sensitivity. A leaked key here can move money, delete data, or impersonate your organisation. Rotate immediately if one is ever exposed, and never let one reach a client bundle.
Can APIKeyConnect see my Square key?
No. The key is encrypted in your browser with AES-256-GCM under a key derived from your master password (PBKDF2-SHA-256, 600,000 iterations). The password never leaves your device and the server stores ciphertext it cannot open. What the server can see is documented in full on the security page, including what this design does not protect against.