iOS Developer
Osmin Vazquez
8+ years moving iOS codebases from one paradigm to the next — while the team keeps shipping. I own technical direction end to end: architecture, framework stack, CI/CD, API contracts, and release.
Five migrations, five employers
The through-line. Each row expands.
Objective-C→Swift Numerator · 2021
The hard part was concurrency, not syntax. Legacy Objective-C carried threading assumptions the compiler never enforced; behaviour that had quietly worked for years surfaced as race conditions the moment it crossed the bridge.
Diagnosed, fixed, and then covered — TDD and a linter introduced to a standing project so the class of bug could not return silently.
MVC→VIPER + RxSwift BBVA · 2018
The architecture came down from the global organization. My job was teaching it: three developers spanning junior, mid and senior — one of whom had built the old MVC app, and one of whom was a React Native developer new to iOS.
I got that engineer's first tickets accepted without knowing React Native myself. Shipped under strict code-coverage requirements.
UIKit→SwiftUI + Combine Numerator · 2021
Nobody had it on the roadmap. I made the case to the Tech Manager that it was even possible mid-migration, then to peers who were new enough to Swift that they had not considered SwiftUI an option — once introduced, they were enthusiastic.
Led roughly ten months of incremental adoption with two senior iOS engineers, setting guidelines and reviewing code. Incremental, never a rewrite.
Intel→Apple Silicon DiGinn · 2022
Inherited a non-runnable, stale project. Made the business case for the migration to stakeholders before doing the work, rather than presenting it as a fait accompli.
Retired stale dependencies in favour of Swift-native features, cut project warnings by ~90%, and left behind a CI pipeline that shipped 20+ releases.
Hand-written→Agentic CHOP · 2025
Team productivity had halted under unchecked AI code generation: output drifted from conventions, and the review burden landed on senior engineers.
I encoded the architecture and review standards into a spec-driven workflow the agents read before writing code — moving architecture from something policed in review to something satisfied before the first line exists. How that works →
Selected work
Experience
Headline and scope are always visible. Expand for the evidence.
Sole owner of the iOS platform in a cross-functional medical research team.
What I owned
- Shipped a medical research app implementing a real-time data pipeline: Bluetooth hardware polling, parallel SwiftUI graphing of live sensor streams, and Cosmos DB persistence through a RESTful API.
- Owned architecture, delivery and release end to end — no one above me on iOS.
- Feature scoping in PI planning, code review, merge approval, and TestFlight releases to QA.
- Resolved a team-wide productivity halt caused by unchecked AI code generation by encoding architecture and review standards into a spec-driven agentic workflow.
The only role where I owned the commercial relationship as well as the code.
What I owned
- Approached about a real business problem; ran on-site discovery and returned with a technical solution, scope, timeline, technology choices and commercial terms.
- Designed and built a custom iOS 17+ app solo — authentication, transaction notification, local storage.
- Established enterprise deployment and device management via Apple Business Manager rather than the App Store.
- Ran weekly client reviews and coordinated with client IT to clear dependencies.
Sole iOS engineer setting technical direction, alongside one engineer per platform.
What I owned
- Inherited a non-runnable, stale project and made the case for the migration before doing the work.
- Root-caused and eliminated recurring crashes in a codebase I had not written — crash rate to near zero.
- Built the safety net: unit tests and CI aimed specifically at the crash class I had just fixed.
- Shipped 20+ releases through the CI/CD pipeline I established; reduced project warnings by ~90%.
- Implemented Firebase analytics, A/B testing and push notifications; cut build times via build schemes.
Proposed the SwiftUI + Combine transition, won approval, then led it for ~10 months.
What I owned
- Set guidelines, proposed patterns and reviewed code for two senior iOS engineers.
- Bridged legacy Objective-C functionality to Swift, resolving the latent race conditions the bridge surfaced.
- Defined and enforced MVVM + Rx; introduced TDD, protocol-oriented design and linting to a standing project.
- Unblocked the deployment-target bump to current (−2n) by paying down technical debt.
Led 2–3 mid-level iOS developers through significant organizational change.
What I owned
- Built user features with UIKit and VisionKit.
- Supported multiple teams; enforced coding standards and reusable design patterns.
- Contributed to a backend migration while keeping the codebase reusable across cruise ships — one codebase, many vessels, each with its own configuration.
Promoted from junior developer to Tech Lead for Mexico within 10 months.
What I owned
- Led 3 developers (junior, mid, senior) rebuilding a legacy banking app in VIPER, RxSwift and TDD under strict code-coverage requirements.
- Taught the team the architectural patterns adopted from the global organization.
- Onboarded a React Native developer into the iOS stack and got their first tickets accepted.
- Conducted interviews and project onboarding; aligned local compliance with global strategy across international teams.
Established the company's technical infrastructure from nothing.
What I owned
- Built the AWS infrastructure; designed APIs and services in Node.js and MongoDB.
- Enabled integration between the public website and internal systems.
Skills
Tags with a dot answer “where did you use this?”
Education
Contact
Engagement & availability
Available full-time (direct or through an EOR), part-time, or as an independent contractor. Active RFC with prior invoicing under RESICO, so a B2B contract with a US or Canadian client needs no new entity. Spanish native, English professional. Open to remote on US hours and to relocation.