We build apps for founders and companies, and we ship our own on the App Store. If your app is stuck at "almost done," we get it through review and keep it stable once it's live.
100% Job Success on Upwork · 76+ jobs · Worked on apps with 50M+ downloads · Former Staff Engineer at Capital One
Production-grade systems, shipped safely.
iOS + Firebase
Cloud Functions v2 backend, App Check security, encrypted Plaid tokens with Secret Manager. Implemented RevenueCat, Crashlytics, RBAC admin panel, and full CI/CD pipelines.
Flutter Migration
Complete migration to Flutter for iOS/Android/macOS. Refined UX, added admin functionality, push notifications, and complex bill/rep tracking modules for Phase 2 expansion.
Production workflows
Stabilized production workflows with a focus on reliability and execution. Implemented production-safe improvements and shipped under real-world constraints.
We don't just talk. We fix critical production issues.
$100K+ earned on Upwork · 3,500+ hours · Washington DC Metro Area
Investigated & fixed duplicate payment race conditions. Optimized API caching strategy for millions of daily requests.
Achieved 3x performance gain and 99.9% app stability. Successfully integrated Apple Pay driving ~7% revenue lift.
Executed critical Django migration (1.6 → 1.7) for production archives without data loss or downtime.
Architected "GoGrocer" and "GoFresha" ecosystem. Complex multi-vendor logic shipped to thousands of developers.
Verified 5-Star Reviews from Upwork
"Carlos is an absolute professional. He came in, diagnosed our crash issues immediately, and had a fix deployed within 48 hours. The stability roadmap he provided was a game changer."
"We needed a senior engineer who could handle a complex migration without breaking production. Tecmanic delivered perfectly. Highly recommended for high-stakes work."
Build a new app, get a stuck one through review, or see how we ship our own.
From the first screen to the App Store release. We pick the stack that fits the project, and our recent work is in Swift and Flutter.
Book a call →Crashes, failed payments, App Review rejections, or AI-generated code that works in the demo but not in production. We find the cause and fix it.
See the stability audit →Countdown Central, Plantsnap and Interpreter: Quick Translate are live on the App Store. We build client apps the same way we build our own.
See our apps →We pick the stack that fits the project. We don't chase hype. We build on battle-tested, enterprise-grade frameworks that scale to millions of users.
Stop losing users to crashes and slow load times. Let's stabilize your build.
Book a 15-min call