Senior iOS Engineer for AI Chat App

We're OneAI, a German company building a European Enterprise AI Platform for the Mittelstand. Multi-tenant SaaS, AI chat with tool-calling across Outlook, Fireflies, HubSpot, ClickUp, GitHub. Backend in production. Hiring a senior iOS engineer to build OneManager — the voice-first mobile interface to our AI platform. OneManager is a thin client over our backend: streaming WebSocket chat, push-to-talk STT, AI tool-call approval cards, meeting intelligence. iOS 17+, Swift 6, SwiftUI, German + English. Long-term hourly, 30 hrs/week steady. You own the iOS codebase end-to-end through TestFlight, including UX (no Figma — see below). WHAT YOU'LL BUILD • Voice-first AI chat (ChatGPT-mobile-style, enterprise-grade, with tool-calling + approval flows) • Streaming WebSocket chat with token-level rendering + reconnect-safe state recovery • Manager Mode: user speaks ("Reply to Jan, meeting moved to Thursday"), AI proposes, user confirms by voice ("Ja/Yes") — full STT loop input + confirmation • Microsoft SSO (MSAL) + Passkey (ASAuthorizationPlatformPublicKeyCredentialProvider) • Multi-tenant account switching, API-key storage in Keychain with biometric protection • APNs push notifications with deep-linking + tenant routing • Interactive push notifications surfacing AI approval cards • Fireflies meeting list (read-only) via our backend connector • File upload via iOS Share Extension (app-group container for shared offline state) • Settings: account, tenant switch, language, TTS voice, GDPR data export DESIGN & UX (read carefully) We do NOT provide finished Figma designs. We provide reference apps (ChatGPT mobile, Granola, Otter, Fireflies), OneAI brand assets, detailed product spec, and on-call backend support. YOU own SwiftUI layouts, transitions, components — you design AS you build, applying Apple HIG plus your own product sensibility. Weekly demos drive UX iteration. This is a Product Engineer role, not "Figma-to-SwiftUI conversion". If you need pixel-perfect designs handed to you, this is not your project. REQUIRED EXPERIENCE • 5+ years native iOS, 2+ apps in App Store you personally architected, designed, AND shipped • Strong UI/UX sensibility — product engineer, not pure coder • Swift 6, SwiftUI, async/await, Combine — modern stack fluency • Real-time streaming: WebSocket, SSE, or live updates shipped in production • MSAL (or AppAuth) for Microsoft SSO + Passkey/WebAuthn integration • Apple Privacy Manifest (PrivacyInfo.xcprivacy) familiarity • Direct freelancer — NOT an agency subcontracting. We will verify. • Fluent English REQUIRED. German is a plus, not required. • CET working-hours overlap of 4 hours minimum (UTC-3 to UTC+5 works) • Daily AI tooling (Cursor, Claude Code, Copilot, Windsurf) — and honest pricing reflecting the productivity gains NICE TO HAVE • AI / LLM-powered iOS UX shipped before • Voice or agent product experience • German language • Xcode Cloud or Bitrise CI/CD • App Extensions (Share, Notification Service) • AVFoundation / AVAudioEngine for audio capture HOW WE WORK • Async-first, daily CET overlap, weekly synchronous demo + standup in Slack • Code in our private GitHub org (SSO + 2FA mandatory) • Mutual NDA + DPA (German AVV) signed before any code access • Staging environment only — no production data on dev devices • EU data residency required for the backend (your dev location can be anywhere) • Our team is already international (Pakistan, Argentina, Europe) — we care about ownership and craft, not location ENGAGEMENT • Two-week PAID TRIAL (~$2,500 fixed): you build Microsoft SSO + Passkey auth prototype against our staging API. Demo decides full engagement. • After trial: hourly contract through 4 phased milestones (Auth done → Chat+STT → Push+Approvals+Fireflies → Share Ext+Settings+Polish) • Long-term commitment opens natural rate negotiation — posted budget range is a starting point, not a ceiling • Decision timeline: shortlist in 5 days, two 45-min calls, contract signed in 2 weeks AI-generated boilerplate proposals are obvious and skipped. We read every proposal. Looking forward to building something real with someone serious. — Mirko Tochtermann, VP Engineering, OneAI