Plain PHP quickstart
There is no adapter package for plain PHP the way there is for Laravel and Symfony; you wire up atoms/client yourself. examples/plain-php/ is a complete, conformance-tested example - use it as a starting point.
Deployment is unchanged by the absence of an adapter: vendor/bin/atoms is the
same binary the framework wrappers shell out to, and it resolves configuration
the same way. With no framework loading a dotenv file for you, the only inlets
for a local token or callback URL are the environment you run the command in
and .env.atoms.<environment>
beside atoms.json. See Configuration and
Deploy.