Zulip could be another option to look into.
They give free plans to open source projects (https://zulip.com/for/open-source/) and "communities" (https://zulip.com/for/communities/) and I think this forum basically meets those requirements.
"Open-source projects, including projects with a small paid team." https://zulip.com/help/zulip-cloud-billing#free-and-discounted-zulip-cloud-standard
@Corwin started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Zulip could be another option to look into.
They give free plans to open source projects (https://zulip.com/for/open-source/) and "communities" (https://zulip.com/for/communities/) and I think this forum basically meets those requirements.
"Open-source projects, including projects with a small paid team."
https://zulip.com/help/zulip-cloud-billing#free-and-discounted-zulip-cloud-standard