I'm not sure I understand the value prop. For localhost, you typically just generate a self-signed certificate that doesn't need to be trusted by everyone, as the dev can just add it to their local store. There are also other services that provide ACME certificates for localhost domains, basically what you do for free (I can't find a link to one but it was posted on HN recently).

If you need a trusted certificate for local dev, something like Cloudflare Tunnels is more valuable as you can have other folks access the service.

My project, getlocalcert.net[1] may be the one you're thinking of.

Since I'm also building in this space, I'll give my perspective. Local certificate generation is complicated. If you spend the time, you can figure it out, but it's begging for a simpler solution. You can use tools like mkcert[2] for anything that's local to your machine. However, if you're already using ACME in production, maybe you'd prefer to use ACME locally? I think that's what Anchor offers, a unified approach.

There's a couple references in the Anchor blog about solving the distribution problem by building better tooling[3]. I'm eager to learn more, that's a tough nut to crack. My theory for getlocalcert is that the distribution problem is too difficult (for me) to solve, so I layer the tool on top of Let's Encrypt certificates instead. The end result for both tools is a trusted TLS certificate issued via ACME automation.

1. https://news.ycombinator.com/item?id=36674224

2. https://github.com/FiloSottile/mkcert

3. https://blog.anchor.dev/the-acme-gap-introducing-anchor-part...