Is it possible to use React without rendering HTML?

It is possible. Below are the possible options:

render() {
return false
}

render() {
return true
}

render() {
return null
}

React version >=16.0.0:

render() {
return []
}

render() {
return ""
}

React version >=16.2.0:

render() {
return <React.Fragment></React.Fragment>
}

render() {
return <></>
}

React version >=18.0.0:

render() {
return undefined
}