The Gateway base URL is:
1

Mint a service-account key

In the dashboard, go to Agent Access → API Keys and create a key with the scopes you need (start with store:write, catalog:write, analytics:read). The plaintext key (sq_agt_…) is shown once — copy it now.Or mint one over the API as an admin (user JWT or an agent:admin key):
The key field is returned only once. Store it in a secret manager.
2

Confirm who you are

3

Build a store from a brief (async)

To make a store that looks like another site, add "like_url":"https://example.com". The store is an exact clone of that site: replace its text and pictures with your own before you publish.
4

Wait for the job and read the result

You authenticated, kicked off an async build, and read the result. Everything else follows this same shape — see Core concepts.

Authentication

Keys, headers, JWT.

Scopes

What each key can do.

Jobs

The async model.

Connect your own agent

Drive it from an agent.