- [ ] Integrate with other data stores
  - [ ] SQLite
  - [ ] PostgreSQL
  - [ ] DuckDB
- [X] Access control with resources
- [ ] Custom definitions
  - [ ] Middlewares
  - [ ] Request decorators
  - [ ] Status messages
  - [ ] Response bodies (in case of error messages)
  - [ ] Resource operations
    - [ ] Single item
    - [ ] Collection
- [ ] Content negotiation
  - [X] Language
  - [X] Charset
  - [X] Media Type
  - [X] Improve content negotiation on success/error responses (able to explicitly select language/media type/charset)
- [X] HTTPS
- [X] Date/Datetime handling (endpoints should be able to accept timestamps and ISO date/datetime strings)
- [ ] Querying items in collections
  - [ ] Better URL parsing for determining target resource/resource IDs (e.g. `/api/users/3/posts/5`, `/users/3` is a query, `posts` is the target resource, `5` is the target resource ID. Different case with `/api/users/3/posts/5/attachments`)
    - [ ] Declare relationship (e.g. `/users/3/posts`)
- [ ] Tests
  - [X] Happy path
  - [ ] Error handling
    - [X] Resource handlers
    - [ ] Generic errors
- [ ] Implement error handling compliant to RFC 9457 - Problem Details for HTTP APIs
- [ ] Create RESTful client for frontend, server for backend (specify data sources on the server side)
- [ ] `EventEmitter` for `202 Accepted` requests (CQRS-style service)
- [ ] Implement RPC endpoints
- [ ] Implement `Vary` header (requires providing a `getHeader()` method in the request object to listen for obtained headers)
- [ ] Add example on serving data as documents using `application/html` type.
- [ ] OpenAPI support
  - [ ] Swagger docs plugin
    - [ ] Plugin support
- [ ] Add option to reject content negotiation params with `406 Not Acceptable`
- [ ] Add `fast-check` for property-based checking
- [X] Split HTTP server from backend core
  - [ ] Add HTTP entrypoint (package?)