Jakub Towarek

I'm an iOS Engineer with 5 years of experience crafting elegant solutions for Apple platforms. I blend technical knowledge with user empathy to transform complex requirements into intuitive interfaces that millions of users interact with daily.

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📡 Technologies

• 💅 SwiftUI UIKit

• 🪢 Concurrency Combine RxSwift

• 🗺️ Git Git Flow Semantic Versioning Changelog

• 🧦 Swift Package Manager CocoaPods Carthage Mint

• 🌍 REST WebSockets gRPC GraphQL OpenAPI

• 🦺 GitHub Actions w/ Self-Hosted Runners Bitrise

• 🤔 Firebase Remote Config Crashlytics Google Analytics Amplitude

• 🧳 App Store Connect TestFlight Apple Business Manager Jamf

🥷 Experience

Wisent | Founding Engineer

May 2025 ~ Present

• built Wisent's native iOS app from zero to one, including on-device LLM, image-generation, and TTS inference with MLX
• provided live user support via Discord, closing the loop between user feedback and product iteration
• build the inference-time runtime that exposes concept directions for read, write, and clamp operations
• build and maintain the contrastive-pair concept-dataset pipelines and per-layer activation capture spanning HuggingFace transformer stacks at sizes from 1B to 405B
• architect Wisent's multi-cloud infrastructure: European HPC allocation for training, a Python/FastAPI backend on AWS (Lambda, EventBridge, EC2, S3, CloudFront), and the app.wisent.ai web application
• re-architected backend from a monolithic A100-coupled service into independently deployable CPU API, inference, and image services, removing model-load from routine releases and reducing deploys from 36-44 min to ~8 min (~78-82% faster) while eliminating routine deploy-time A100 usage (~36-44 A100-min saved per deploy; 100% GPU deploy-cost reduction)
• ported on-device speech/LLM inference stack to iOS by implementing NeuCodec in Swift/MLX and extending Swift Transformers/CoreML tokenization support, covering a 24kHz / 50Hz neural audio codec, 2048->1024 projection, 12-layer / 16-head Transformer, ISTFT decoding, safetensors weight loading, and Python-reference parity tests, enabling server-free real-time TTS/voice inference on Apple devices
• led cross-platform, multi-layer safety/feed moderation across iOS, Android, and web by migrating home/search/category feeds to server-filtered RPCs, adding automated NSFW/pending gating plus an admin moderation panel with calibration tooling, and replacing duplicated client filters with consistent policy enforcement across 3 product surfaces

SumUp | iOS Engineer, Online Store Tribe

February 2023 ~ February 2025

• own the full development cycle for key merchant-facing features, including order management used by over 100,000 merchants
• fix and contribute to the design system, including parts written in Obj-C and consumed across 5 tribes
• take part in design reviews, providing actionable feedback and suggesting "quick wins" for UI / UX designs on iPhone and iPad
• start an app-wide migration to SwiftUI
• monitor app stability via Crashlytics, feature performance via Google Analytics, and overall system health via traces on Honeycomb; crash-free sessions improved from 98.7% to 99.6%
• effectively collaborate within Spotify's Agile model (tribes, squads, chapters) to deliver features with global impact, like Customer Directory and integrations from different tribes
• research spikes and summarize solutions, for example implementing a rich text editor with quill.js via WebView as a less resource-intensive alternative to creating a native solution
• improve OpenAPI definitions to correctly express behaviors and types, making iOS client generators less error-prone

Dispo | iOS Engineer

January 2022 ~ February 2023

• independently implement new features in an existing codebase
• redesign, optimise and expand capabilities of real-time image processing system
• work closely with design team on the release of image editing suite and introduction of new camera effects
• maintain stability by monitoring and prioritising crashes and non-fatal errors
• improve performance and readability of asset caching mechanism using async await pattern
• prepare features to be released as part of A/B experiments in order to minimise potential negative outcomes
• create and upload new app versions to the App Store Connect
• progressively refactor The Composable Architecture to MVVM with SwiftUI, Combine and async await
• experiment with disparity-based depth measuring techniques for advanced 3D photo effects

Netguru | iOS Research and Development Lead

August 2021 ~ January 2022

• coordinate AR virtual try-on app development
• filter iOS trends and news to select
• advise and provide feedback on blog posts and presentations
• align team members' needs with research topics

Netguru | iOS Developer

January 2020 ~ January 2022

Design System For Food Delivery Company

• design common interfaces for Android, iOS, and Flutter
• write extensive documentation
• cover components with screenshot tests and UI Tests

Voice Assistant App For Easy CRM Access

• lead architecture design with SwiftUI and Combine
• implement on-device speech transcription
• interact with serverless backend via websockets
• advance communicated project value to stakeholders through analytics
• monitor and prioritise crashes and errors

IoT App For Startup

• add new features in obscure codebase
• fix critical security vulnerabilities in Firebase Authentication

Netguru | Junior iOS Developer

October 2019 ~ January 2020

💡 Open Source

wisent

Co-author and maintainer of the reference representation-engineering library for text LLMs: 342 GitHub stars, 32 forks, over 200,000 downloads, latest release v0.11.43 (2026-05-18), continuous releases since 2024.

SwiftOLED & SwiftGFX

Two Swift libraries developed while tinkering with Raspberry Pi and SwiftOnArm. I wanted to use Swift, but there wasn't a library that would let me display data on an external OLED display, so I created two - one for drawing a pixel buffer on the screen, and a second graphics library capable of rendering text to a pixel buffer. Both have nice READMEs. I even got some contributions.

📢 Languages

I am fluent in English - I hold an IELTS C1 certificate.

📚 Education

After finishing technical high school and passing my IT Specialist certification, I started an Applied Computer Science major at Newcastle University in the UK. Shortly after, I got accepted for a junior iOS developer position, so I dropped out.