Investment Nerds

Four apps, one company

The landing site has to load fast for somebody who has never heard of the product. The auth app handles registration, verification and password resets, and is the one surface where a mistake is a security incident rather than a bug. The client app is where investors spend their time. The admin console is where the team runs the business.

Building those as one application means the marketing page ships the admin bundle. Building them as four separate codebases means four component libraries drifting apart until the product stops looking like itself. So they are four applications in one workspace, sharing seven packages: the design system, the layouts, the auth client, the API layer, the generated types, the hooks and the build config.

The practical test of that decision is a colour change. Adjusting a token in the shared theme moves all four apps at once, and nobody has to remember that the admin console also has a button.

The contract with the backend

The frontend and the backend were built by different people, which makes the API the place where a project like this usually goes wrong. A field gets renamed, the frontend keeps compiling, and the failure arrives in production as an empty column nobody notices for a week.

So the types are not written by hand. They are generated from the backend’s OpenAPI description and paired with zod schemas, which means a renamed field is a build error on my side rather than a blank space on somebody’s portfolio page. It moves the cost of a breaking change from the user back to the developer, where it belongs.

Above that sits a single RTK Query layer shared by every app, with a websocket client for the data that cannot wait for a refetch. Market prices move; the components that read them subscribe rather than poll.

The console nobody sees

The admin app is a third of the frontend and none of the marketing. Stocks, currencies, exchanges, brokers, companies, users, API keys and forum moderation each need list, detail, create, edit and audit, and every one of them is somebody’s job rather than a demo.

It is also where the shared packages earn their keep. The console is built almost entirely from the same component library as the client app, so the surface the team uses all day gets the accessibility work, the keyboard handling and the loading states that were done once for everybody.

Where it stands

The platform is self-hosted on the company’s own infrastructure rather than deployed to a public host, so there is no link on this page to click. The frontend ships as Docker images built from the workspace, one per app.