It is nice, but not totally free or open source:
"WebContainers rely on hosted proxies and server-side acceleration to enable truly instant development environments. By obtaining a WebContainer API license, your business can gain access to higher API rate limits, uptime reliability, and a range of benefits designed to help you maximize the potential of the WebContainer API in your organization.
Licensing is required for production usage of the API in a for-profit setting (feel free to prototype as much as you like without a license). If you're using the API to meet the needs of your customers, prospective customers, and/or employees you need a license to ensure continued access to the API as you scale.
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