SvelteKit with Nginx returns response error 500

Question

Im trying to build SvelteKit project and host it on a server with nginx, using @sveltejs/adapter-static. The app works fine when developing locally but when build it and upload it im getting 500 JSON.parse: unexpected character at line 1 column 1 of the JSON data for some of the routes.

The routes in problem are sourcing their data from a json file (part of the project).

My folder structure is:

src/
├── data/
│   └── my_data.json
└── routes/
    ├── api/
    │   └── something.json.js
    └── area/
        └── [method].svelte

something.json.js

import * as siteData from "../data/my_data.json";

export async function GET({ url }) {
  const param = url.searchParams.get("method");

  const body = siteData[param];

  return {
    body
  }
})

[method].svelte

<script context="module">
    export const load = async ({ params, fetch }) => {
        const response = await fetch(`/api/something.json?method=${params.method}`);
        const posts = await response.json();

        return {
            props: {
                posts
            }
        };
    };
</script>

<script>
  export let posts;
</script>

<div>
  <!-- do something with "data" here -->
</div>

svelte.config.js

import adapter from '@sveltejs/adapter-static';

/** @type {import('@sveltejs/kit').Config} */
const config = {
    kit: {
        adapter: adapter({
            pages: 'build',
            assets: 'build',
            fallback: 'index.html',
            precompress: false
        })
    }
};

export default config;

nginx.conf

http {
   server {
      listen 80;
      include /etc/nginx/mime.types;

      location / {
         root  /usr/share/nginx/html;
          
         try_files $uri $uri/index.html $uri.html /index.html;
      }
   }
}

With this setup:

• http://localhost:3000/area/method1 displays all ok

• http://my-server.com/area/method1 displays:

  

My (wild) guesses:

• this will never work because there is no actual back-end to handle the endpoint code
• nginx misconfiguration when trying to call/serve /api/something.json