Founding iOS Engineer at Sonia (W24)

About Sonia

One in five adults struggles with their mental health each year and many will never see a therapist. Costs are high, waitlists are long, and stigma is still a real barrier for people to not seek help. Suicide is one of the leading cause of death for young people. Therapy works, but it doesn’t scale.

We're building a safe AI therapist that's clinically as effective as the best human therapists - accessible to everyone, at a fraction of the cost, and available anytime. We've recently had a major breakthrough. In our clinical research, we're now seeing significant improvements in anxiety and depression symptoms after just 2 weeks of use. And we receive daily messages about how Sonia is changing lives.

We're a 6-person team in San Francisco, backed by Y Combinator, Moonfire, and founders of Verkada, Reddit, and Instacart ($3.5M raised).

The Role

Sonia is a voice-first iOS app built in SwiftUI. This isn't a standard mobile app. It's about a real-time, emotionally sensitive conversation - all tightly integrated with AI. You'll own the iOS app end-to-end and ship features that positively impact people's mental health. From everything that we build, your work is what people interact with directly.

Problems you'll work on

• Build and improve the core user experience in our iOS app
• Iterate on key user flows, run A/B tests to figure out what works
• Building on a real-time WebRTC-based voice interface that feels calm and trustworthy during vulnerable moments
• Collaborating with the rest of the team to understand our users and improve the product

What the work looks like

• Ship features fast with high ownership
• Track, analyze and improve the user experience based on data analytics (we use Mixpanel, and our own data tracking system)
• Work closely with our designer and AI engineers to define what we build
• Touch backend code when needed (FastAPI, Postgres, Redis)
• Use AI tools heavily — we expect you to juggle multiple Claude Code instances at a time :)

Tech Stack

• SwiftUI (iOS-first)
• Figma (you’ll collaborate with our Designer there)
• FastAPI, Postgres (backend — helpful if you can navigate this)
• All kinds of APIs and model providers like OpenAI, Anthropic, Deepgram, ElevenLabs

Culture

We're kind to each other, work hard, and we are thoughtful about what we're building. We work 6 days a week together in our office in downtown SF. It's challenging, but when your work helps someone get through their day a little easier, it doesn't feel like sacrifice. We get free lunch and dinner and nerd out about whatever we’re currently working on. And we’ll pay your (human) therapy bills :)

Who We're Looking For

• 3+ years of experience shipping SwiftUI apps to the App Store
• AI-native — you use Claude, Cursor, or similar tools constantly
• Comfortable with ambiguity and high ownership
• Bonus: experience with real-time audio, streaming, or voice interfaces

A few user stories from the past weeks

• A women from the south who lives in a rural area with no therapist in proximity from her Blue Shield insurance. She has been unemployed for the past 15 years and told us that due to her chats with Sonia she gained the courage to apply for jobs again. A few days later, just before her user interview with us, she got accepted to her job and is now employed again.
• A person from Alabama who had such strong OCD and anxiety that they always needed to turn around with the car 3-4 times to check whether they actually turned off the stove. Sonia helped them get it down to one.
• The parent of 2 incarcerated sons, has built out a mantra with Sonia and is now able to go through her days with more acceptance and peace. Something that according to her, her weekly Monday morning therapist that she has been seeing for a long time hasn’t managed to achieve.

Interview Process

• Send us your best projects to [email protected] (would love feedback on the UI of Sonia)
• 15min phone screener
• 30min chat with all co-founders
• Take-home remote assessment
• 2 day onsite trial in SF