Oniel Rosario, iOS engineer

I shipped an AI music app solo: SwiftUI client, Live Activities, SSE streaming, serverless backend. Before that, 4 years on an app with 10M+ weekly users.

Oniel Rosario, iOS engineer. I shipped an AI music app solo: SwiftUI client, Live Activities, SSE streaming, serverless backend. Before that, 4 years on an app with 10M+ weekly users.

About Oniel

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With a focus on creating seamless collaboration, I believe in fostering open communication to ensure that every team member's voice is heard. I prioritize building strong relationships across remote teams, creating an environment where innovation thrives, and everyone feels empowered to contribute.
I prioritize collaboration, fostering open communication
Drag the globe!
I'm very flexible with time zone communications
Swift · SwiftUI · ActivityKit · App Intents · Redis
My tech stack
SwiftSwiftUIActivityKitApp IntentsCombine
RedisTypeScriptTuistFastlaneDatadog
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I engineer robust, scalable Apple ecosystem solutions that deliver premium user experiences under real-world constraints.
Bridging complex Native iOS Architecture with intuitive, high-performance UI.
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Inside my latest R&D
Currently building Crossed My Mind (hardware & connection app) and Noema AI Radio (AI music generation app).
Want to talk iOS? Grab 15 minutes.
Oniel RosarioInteractive Portfolio Assistant

Ask Oniel

Ask questions about my iOS architecture background, Noema AI Radio, 4 years at Ibotta, or my engineering approach.

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Hi! I'm Oniel's portfolio assistant. Ask me anything about his iOS engineering background, Ibotta tenure, AI projects, testimonials, or availability for senior roles.

A small selection of Recent Projects

What people are saying about me

  • “Working with Noema Studio was one of the best decisions we made launching our business. What sets Noema apart is that they lead with vision and build technology that supports it. They took the time to truly understand who we are — a bilingual, women-owned agency rooted in community — and brought together every element, from design to strategy to user experience. Noema sees the whole picture. They think beyond the website itself and analyze how you can utilize technology to connect with your target market and enhance the user experience. The result is a site that’s not only beautiful and fast, but purposeful. If you’re looking for a partner who combines real creative vision with technical expertise and genuine care, Noema Studio is who you call. We couldn’t be happier.”
    Florangel Slaughter
    Florangel SlaughterCOO, Herencia Rosario Insurance Agency
  • “Working with Noema on the launch of Herencia Rosario Insurance Agency’s website was a great experience. From the beginning, they took the time to understand our vision and created a website that truly reflects our brand. The website and integrated alert system have made it easier for us to manage inquiries, stay organized, and connect with potential clients. Their attention to detail, responsiveness, and commitment to bringing our ideas to life made the entire process seamless. I would highly recommend their services to anyone looking for a reliable and talented professional.”
    Daniela Rosario
    Daniela RosarioCFO, Herencia Rosario Insurance Agency
  • “I worked with Oniel for more than 3 years and he has proven to be a steady and capable engineer! He is a self-sufficient engineer who is consistent in his ability to deliver on commitments. He strives in helping others achieve theirs as well. With his time here he expanded his technical knowledge beyond iOS into backend systems, always looking to learn the next thing. Oniel is type of engineer you want on your team. He is quick to learn, committed to his work, and dedicated to strategy and goals of the company!”
    Heather Shannon
    Heather ShannonSenior VP of Engineering, Data, and Operations, Ibotta Inc.
  • “Oniel is a prolific contributor, solid engineer and important contributor to team culture. It was great to work with him, specifically the opportunities we had to discuss new opportunities in our iOS system architecture.”
    Mike Woolley
    Mike WoolleyDirector of Engineering, Ibotta Inc.
  • “Oniel is a seasoned iOS engineer who takes time to raise teammates around him up! He personally mentored me during my time at Ibotta. He always makes time to explain complicated concepts about architecture or offer career advice early in my career. Oniel is a great engineer who makes other engineers great.”
    Luke Atkins
    Luke AtkinsIntern, iOS Engineer, Ibotta, Inc
  • “I'm thankful to have worked alongside Oniel for almost 3 years. He has consistently shown initiative by taking on new challenges, responsibilities, and leadership roles. Oniel always has his eye out for future technologies and how they may benefit our product, striving to keep our team at the forefront of industry trends. He leads his teammates by teaching, sharing his knowledge generously, and encouraging communications. Oniel has always made himself available for my coworkers and I to ask questions, offering support and guidance whenever needed. His pull request feedback is solid and constructive, helping to improve the overall quality of our codebase. Oniel is a consistent team member who delivers high-quality work. Beyond his professional skills, he is also a great person to work with, helping foster a positive and collaborative environment.”
    Andy Geipel
    Andy GeipeliOS Engineer, Ibotta Inc.
  • “Over the last few years, Oniel has been a force multiplier within the mobile engineering team by mentoring others, teaching out new APIs and technologies, and recommending architectural improvements, all while leading several high-impact projects and contributing to engineering-wide leadership initiatives. Oniel is an incredibly dependable, proactive, and detail-oriented engineer who is a pleasure to work with - I strongly recommend him for any software development position.”
    Brett Markowitz
    Brett MarkowitzSenior iOS Engineer, Ibotta, Inc.
  • Crossed My Mind logo
  • Noema logo
  • Ibotta logo
  • Gather AI logo
  • Electrify America logo
  • Herencia Rosario Insurance logo

Why Hire Me?

My Work Experiences

Noema AI RadioSept 2024 to present

Founder & iOS Engineer

Built and shipped an AI music generation app to the App Store on my own. Generation takes 10 to 30 seconds, so I built a progress pattern that makes the wait feel short, plus a streaming pipeline (SSE with polling fallback and stall detection) that survives app termination and network loss. Live Activities, APNs and Siri via App Intents keep the state in sync. RevenueCat handles subscriptions, and auth uses refresh-token rotation with replay detection.

Ibotta TechnologiesDec 2020 to Aug 2024

iOS Engineer

Core engineer on an app with 10M+ weekly users. Co-led the Dynamic Island launch (shipped early, +15% task engagement on iPhone 14 Pro). Co-led the Walmart and Dollar General account-linking integrations (7-figure revenue impact). Cut memory leaks 25%, grew test coverage 40%, and mentored interns and associates.

Sulzer (Electrify America)May 2020 to Nov 2020

iOS Engineer

Took Electrify America’s EV-charging app from designs to production, with reusable SwiftUI components and CoreData utilities along the way, increasing team velocity by 20%.

Independent ConsultingJune 2019 to Apr 2020

iOS Engineer, Indie / Contract

Migrated legacy iPad apps from Objective-C to Swift and UIKit, including an ARKit warehouse barcode scanning drone application for Gather AI. UI response time dropped 40%.

Wanna learn more? Download my full CV

How I Use AI

Practical agentic engineering: accelerating delivery while keeping core architecture, security, and production reliability strictly human-owned.

Workflow

Claude Code Every Day

I use Claude Code every day for planning, debugging, and first drafts. I make it argue the design before I write anything, and I read every line it produces.

Security

Human Ownership Boundary

Anything touching auth, payments, or architecture is mine. Tests too. Agentic tooling accelerates boilerplate, but core security, money, and system integrity never get delegated.

Production

Carrier Proxy Watchdog

On Noema, AI missed idle-connection kills on carrier proxies, and my streaming pipeline stalled silently a week after launch. I fixed it with heartbeats and a watchdog. That’s the kind of production reality I check for.