Bill V

@billvivino
5.0(5)

Senior Software Developer, SwiftUI, Unity, React, Kotlin, Replit, Node

United States
English
About me
I help startup founders and established businesses launch high-quality iOS, Android, Web, and cross-platform apps fast. As a senior mobile developer, I’ve shipped dozens of apps using SwiftUI, React Native, React Web, Kotlin, Unity, Firebase, AWS, and Azure, including an AR app for NASA’s Visitor Center at Goddard. Whether you’re building an MVP, adding features, or integrating with cloud services, I bring solo execution and clean delivery. No hand-holding required. Available for: Full builds Debug Scaling U.S.-based | Rutgers CS graduate (4.0 GPA) | Available for hourly or fixed-scope work... Read more

Skills

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billvivino
Bill V
Offline • 
Average response time: 1 hour

See my services

Help/Consultation
I will build or fix your swift kotlin react or unity app hourly
5.0(1)

Want to work on an hourly basis?

Tell Bill V what you need.

$250

/

hour

Portfolio

Work experience

1OR Health Surgical Platform – Full-Stack Engineer

1OR Health • Freelance

Mar 2025 - Present1 yr 3 mos

TypeScript | React | Node.js (Express/TSX) | PostgreSQL (Drizzle ORM) | FHIR (STU3 & R4) | WebSockets | SwiftUI | Kotlin MAR 2025 – PRESENT Inherited a high-risk, vibe-coded prototype and led a complete re-architecture into a secure, scalable, production-ready surgical readiness platform. Delivered a robust full-stack system that successfully progressed from unstable MVP to funded pilot deployment with live clinical workflows. Designed and implemented a dynamic preoperative readiness and notification system that evaluates workflow status, timing, and facility rules to deliver targeted, context-aware alerts to surgeons, admins, vendors, and support staff — reducing noise while maintaining accountability. Redesigned the database schema to support high-growth needs (surgeries, inventory, sterilization tracking, reporting) — enabling significantly faster feature development and analytics. Integrated hospital scheduling systems for seamless appointment lookup, booking, and authenticated access flows. Strengthened security and user experience: rate-limited authentication, theme persistence, deep-link handling, and real-time state synchronization across the application. Key Outcome: Transformed a chaotic early-stage prototype into a fundable, pilot-ready product that supports real-world clinical operations with improved reliability and reduced operational friction.

MainlineV1 – Dual-GNSS Yield Calculator (iOS) - Lead Swift / GIS

Mainline • Freelance

Jan 2025 - Dec 202511 mos

Swift | SwiftUI | Firebase Auth/Firestore | Combine | MVVM Integrated Trimble GNSS SDK (TMM reference) to stream real-time position data from two external receivers; exposed Set Start Point actions for each device and captured boom-to-boom width on every Calculate Yield press. Computed treated-area polygons with the shoelace formula using successive width × distance segments, feeding live application-rate and coverage metrics to the UI. Wrapped the Objective-C demo from the vendor SDK in a pure-Swift MVVM layer, keeping interop minimal while matching TMM behavior and UX. Devised hardware-independent test harnesses that replay NMEA logs, allowing most development without a physical receiver (hardware shipped only for final field validation).

5 Reviews
5.0

(5)
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(0)
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(0)
Rating Breakdown
  • Seller communication level
    5
  • Quality of delivery
    5
  • Value of delivery
    5
1-5 out of 5 Reviews
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Most relevant
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    image-docs

    tonyla818

    US

    United States

    5

    Bill exceeded my expectations. I love working with honest and hard working individuals. Looking forward in working with him again.

    Up to $50

    Price

    3 days

    Duration

    gig

    Help/Consultation

    Helpful?
    Yes
    No
    A

    allouismusic

    US

    United States

    5

    Bill did an amazing job with my job request! I am excited to share this product with my team and increase my sales. Thank you again….excellent work!

    Up to $50

    Price

    2 days

    Duration

    Helpful?
    Yes
    No
    O

    osib0013

    US

    United States

    5

    I couldn't be more impressed with the work done! Bill handled the upload of our Unity OS build seamlessly and efficiently. They demonstrated great attention to detail, ensuring the build was properly prepared, and uploaded without any issues. Plus, Bill's ability to communicate clearly and professionally...

    Up to $50

    Price

    1 day

    Duration

    Helpful?
    Yes
    No
    C

    chinonso1996

    Repeat Client

    US

    United States

    5

    Bill is excellent at his craft and was patient in both understanding what I am trying to accomplish and in explaining technical concepts that are beyond my current knowledge. Bill is golden. Responds quickly to boot.

    $600-$800

    Price

    4 weeks

    Duration

    Helpful?
    Yes
    No
    C

    chinonso1996

    Repeat Client

    US

    United States

    5

    Bill is excellent at his craft and communicates well so that buyers know what their money is being used to do

    $600-$800

    Price

    10 days

    Duration

    Helpful?
    Yes
    No