Web-portal. Clear and mobile-friendly web-portal.
These parts (if there are such) have to be developed using different platforms or technologies:
Web-app. There is variety of frameworks that can be integrated with Directual: React JS, Angular, Vue.js, JQuery, Vanilla JS. Or, you can use such site builders as Webflow, Tilda, Squarespace, etc. Directual web-pages can be embedded in any web-page. Also, Directual provides the boilerplate for React JS.
Mobile app: iOS or Android app can use API-methods configured on Directual.
Third-party systems can be integrated with backend on Directual.