Hi, I'm

Alejandro Arjonilla

Software Engineering Consultant

10+ years building mobile apps, scalable backends, and AI-augmented workflows across FinTech, blockchain, and SaaS.

Experience

Nov 2024 — Present

Software Engineer · Full-Stack

Control

Built the iOS app from scratch with scalable architecture. Collaborated on backend and frontend web app. Championed AI-augmented workflows — best practices for LLMs in code generation, review, and testing.

SwiftSwiftUINode.jsReactAI WorkflowsClean Architecture

May 2023 — Apr 2025

Mobile Lead

Bitstack (YC S22)

Led mobile dev for a YC-backed FinTech. Maintained legacy app while building a scalable new Flutter app. Integrated Apple Pay, Google Pay, Firebase.

FlutterFirebaseApple PayGoogle PayCI/CD

Nov 2021 — May 2023

iOS Engineer

Hoseki

Built Bitcoin infrastructure iOS app from scratch. Blockchain exchange APIs, backend (Node.js), UX collaboration.

SwiftNode.jsBlockchain APIs

Oct 2018 — Nov 2021

iOS Developer

Xapo Bank

Core iOS team that re-launched Xapo app on time. ReactiveSwift, Realm, Firebase, CircleCI. Fully remote, global FinTech.

SwiftReactiveSwiftRealmCircleCI

May 2017 — Oct 2018

iOS Developer Lead

United Cuisines

Led mobile team, coordinated external consultants on enterprise digitalization projects.

SwiftTeam Lead

Mar 2016 — Aug 2018

iOS Developer

Videona Socialmedia S.L.

Built video editing apps from scratch (Videona, ViMoJo, Kamarada). AVFoundation, real-time media.

SwiftAVFoundationVideo Processing

Nov 2015 — Mar 2016

Junior iOS Developer

Integrasys S.A.

SwiftiOS

Skills

Mobile

SwiftSwiftUIUIKitFlutterDartXcodeAVFoundation

Backend & Web

Node.jsNext.jsReactTypeScriptSupabaseFirebaseREST APIs

Architecture & DevOps

Clean ArchitectureMVVMTDDCI/CDGitHub ActionsGit

AI & Tooling

ClaudeGitHub CopilotPrompt EngineeringAI Code ReviewPlaywright

Education

MBA

IEBS Business School

2019 — 2021

B.Sc. Audiovisual Systems Engineering

Universidad Carlos III de Madrid

2008 — 2013

Entrepreneurship

PROSFY

Co-Founder

2021 — Present

Language

Spanish

Native

English

Professional

Highlights

10+ years fully remote, distributed teams

Shipped apps used by 100K+ users

Experience across US, EU & LATAM markets

Former national team athlete — Silver Medal, Ibero-American Championship

Contact