Jim Hill

I would not recommend RabbitMQ. It does not scale well.

I would recommend Redis if you want non-durable, fast, distributed, and scalable messaging. Note it has almost no guarantees around at least once delivery and similar so you will have to handle that.

I would recommend Kafka if you want the whole deal with a bit more bloat. It is durable, fast, distributed and scalable. It has few downsides other than a learning curve and higher cost.

I currently use Redis as my message queue and plan to upgrade to Kafka in Q1

Whenever choosing a tech stack start with the simplest solution. WordPress might be a simple solution for all your problems with little development experience. However the booking feature with backing database may require more coding. If that is the case, a PWA is not a bad choice. I have not personally used svelte but it looks to be primarily a prebuild static site generator. This may make some runtime elements difficult like logins or reactive behaviors. I don't think you need those heavily so Svelte might be a good fit. If you need something more heavy duty based on React, consider Gatsby. I have found it is a good combination of SPA and static site features and can still be hosted on a CDN like Cloudflare. Svelte is newer to the game (but newer is not always better). Regarding the backend API, I have heard good things about FaunaDB. However, if you want to use the sql database you already have you could drop an Apollo server right in front of it to add the graphql features you crave. GraphQL is a great modern way to build an API. I endorse it. All my APIs are GraphQL. Regarding Deno, it is very new to the game... very new. I am excited to move all my stuff off nodeJS to Deno someday, but be aware as it's new it may have gaps and cause some headaches where NodeJS will just work and has the best package ecosystem in the world, NPM. For example, to use Apollo Server you'd have to use NodeJS instead of Deno. Overall, your choices are cutting edge so I think it would result in a sleek app, but know that with the newest comes the most change and learning difficulty. Also, I endorse using cloudflare for static site hosting. It is awesome. If you have any questions, don't hesitate to reach out for more specifics.