# 11 — Multiplatform Clients

**Rank 23 of 28** · Tier C · `IOS/`, `Android/`, `app/web-platform`
**Stack:** SwiftUI + Swift Concurrency; Kotlin + Jetpack Compose + Gradle; Next.js + TypeScript + Playwright + vitest

> **Why this ranks here.** It is a large body of real work and it proves range —
> but a distributed-systems loop does not hire on it. Lead with the backend;
> use this to answer "have you owned a product end to end?" (yes, on three
> platforms).

---

## iOS — 611,426 lines of Swift, 1,200 files

Thirteen product modes in one app:

| Mode | Files | Lines |
|---|---|---|
| Dating | 147 | 90,161 |
| Array | 122 | 90,017 |
| Billboard | 128 | 57,669 |
| Main | 160 | 37,714 |
| BoxOffice | 45 | 20,407 |
| Universal | 26 | 17,530 |
| Global | 110 | 17,246 |
| OpenHouse | 57 | 9,294 |
| Identity | 51 | 8,051 |
| Registration | 13 | 6,072 |
| Vitals | 14 | 2,582 |
| Login | 5 | 1,427 |
| Storefront | 5 | 820 |

Notable engineering: `BillboardAudioEngine` with an `AudioEngineActor` over
AVPlayer (Swift actors for audio-thread safety), a `JamzAudioEngine` doing
**vDSP FFT constellation matching on-device**, gRPC-generated gateways from the
shared protobufs, and WebRTC via `stasel/WebRTC 147`.

## Android — 19 modules, Kotlin/Compose

A port of the iOS app to Kotlin + Compose. Toolchain installed, builds green.

```
core/     network · persistence · proto · security · universal
feature/  array · billboard · boxoffice · dating · globalchat · identity
          login · mating · openhouse · shell · solomon · storefront · vitals
```

Convention-plugin Gradle setup (`build-logic/`) — the correct way to keep 19
modules consistent.

**The valuable part is what was *not* done:** seven pre-existing iOS defects
were found during translation and **reproduced deliberately rather than
silently fixed**, so the two platforms stay behaviorally identical and the bugs
get fixed once, on purpose, in both. That restraint is a strong engineering
signal.

## Web — Next.js platform

`app/web-platform` — Next.js App Router covering every product mode (array,
auth, billboard, billing, bizz, blog, boxoffice, careers, dashboard, dating,
globalchat, identity, login, mating, openhouse, storefront, plus legal/press/
privacy/promo surfaces). **Playwright e2e + vitest**, buf-generated TypeScript
clients from the same protobufs the backend serves.

## Interview surface this opens

- Swift actors and structured concurrency for real-time audio
- On-device DSP: FFT, constellation fingerprinting, and why it runs on-device
- Generating typed clients for three platforms from one protobuf source
- Cross-platform behavioral parity, and why you reproduce a bug instead of fixing it mid-port