Felipe Kellermann @felipek

• Contact: me@felipek.com | felipek.com
• Resume: PDF | HTML | MD | Linkedin
• Networks: @felipek almost everwhere

Mobile consulting and creating products since the original iPhone SDK was released, focusing on native tools (UIKit, Objective-C) and backend (Django, Linux, IaaS). Recently supporting a SaaS product that already transacted millions of orders. Before that, worked as a C developer for embedded systems and controllers, security and networking solutions, and created a pluggable proxy (SOCKS and HTTP) while also supporting Linux deployments and embedded (BusyBox). Bachelor's degree in computer science.

• Areas: Mobile (iOS), Operating Systems, Networking, Protocols
• Systems: Darwin (macOS, iOS), GNU/Linux and BusyBox, FOSS
• Languages: Python / Django, Objective-C / Swift, C, shell script
• Researching: OpenTelemetry, Ansible, Rust, SwiftUI

History

Critical TechWorks: February 2022

Critical TechWorks is a joint venture to lead the future of motion. Established in 2018, Critical TechWorks is a company formed as a result of a partnership between BMW Group and Critical Software. Critical TechWorks is exclusively put together to support BMW in building software for its future driving machines.

Linux embedded and Python automation.

Negotti: November 2012 - February 2022

Started as a product of my previous company (Nyvra) that offered development services. Focused on creating a subscription-based product for a common ask of our customers at the time the iPad launched: a "digital catalog with dynamic sales force automation, fast, simple and offline for smartphones and tablets, combining products with marketing and sales."

Founder

• Created a new company to focus on a single subscription-based generic product
• Converted an app/library of the previous company (Nyvra) to a complete product
• Worked on the infrastructure (AWS, Linux), backend (Python, Django), app (iOS)
• Supported the multi-tenant solution serving both small and large customers
• Scaled to support thousands of daily devices and tens of millions of orders
• Automated several tasks from business (billing) to monitoring (alerts, events)

Backend

• Infrastructure: AWS (EC2 CloudWatch S3 CF Route53 Glue Athena EBS SNS SQS)
• Systems: GNU/Linux (Ubuntu), Fabric (deploys, automations), MySQL (database)
• API: Django (from the early days of 1.2 to 4.0) and Python (moved from 2 to 3)
• Caching: Custom Django ORM caching with Redis (models), Nginx/Memcache (HTTP)
• Observability: Prometheus/statsd/Grafana (metrics), CloudWatch/Athena (logs)
• Other: Jupyter (scripts, analysis), Celery (queueing, workers) and Supervisor

App (iOS)

• Reliable iOS app that started in the early days of 4.3 and 5.0 to modern 15+
• Support for a wide range of models / devices (universal) and system versions
• Completely generic app supporting custom targets and several "feature flags"
• Scripting engine (JavaScriptCore) for writing complex custom business rules
• Templates engine supporting custom print (HTML, PDF) and others (CSV, XLSX)
• Common core with targets for branded apps using automations (Fastlane)

Other

• Integrations in Python for several systems/customers (SQL, WS/REST/JSON, CSV)
• Abstracted integrations (SQLAlchemy, Requests) mapping to Python/Django (ORM)
• Structured logging and ETL pipeline with automations to auto alert customers

Nyvra: November 2009 - June 2016

Started a company to offer consulting and development services. Even though I started developing for the iPhone when the SDK was first released in 2008, only after publishing the first apps in 2009 that I decided it was time to create indie apps while supporting and helping other companies. Later on, started a new company (Negotti) in parallel to consulting jobs to create a SaaS business. Nyvra is ROT13 for Alien.

Founder

• Hired and managed 4 other people organizing remote work using early SaaS tools
• Organized work using initial versions of GitHub, Basecamp, Highrise, Zendesk
• Consulted for customers large and small in time-based and project-based jobs
• Trained experienced developers getting started on Objective-C/Foundation/UIKit

Consulting: 2009 - 2014

• Zenvia: Worked on many consulting jobs for the leading mobile company in Brazil
• Mobo: Created the iOS app for the pioneering mobile coupons company in Brazil
• Zynk: Created the iOS app for the startup that was a later acquired by Zenvia
• Other: NDrive (Portugal), Jornal NH, Pacotes, and many others

Training: 2010 - 2012

• Created a short lived company treinamentos.mobi to offer courses on mobile
• Created a new iOS/Objective-C course at a well-established trainings company
• Created custom course on iOS Security (portuguese) for a large local bank
• Gave talks on iPhone/iOS development at local mobile events and communities

Project - NearCinema (iPhone): 2008 - 2009

• Used the initial versions of the iPhone OS SDK when it was released
• Used early versions of CoreData, CoreLocation, CoreGraphics, MapKit and others
• Created an engine for on-device requesting/scraping HTTP movie/theather data

Project - FoodBrasil (iPhone): 2009 - 2010

• Created and released the app in 2009 using the then-improved SDK features
• Used newly released technologies in the SDK like MapKit, APNS, and 2x assets
• Maintained the app as it stayed at the top of the App Store charts for months

Project - MobileGuides (iPhone, Android): 2011 - 2012

• Managed the creation of a framework/tools/backend for conference apps
• Developed apps for some conferences using these tools and technologies

Hewlett-Packard Brasil: July 2008 - October 2009

Worked as a software developer using low-level C in a project that involved porting the architecture of a large NAS controller operating system firmware. This is exactly the same job position as the previous job but hired by Hewlett-Packard Brasil. Left HP to create my own company (Nyvra) when the iPhone OS SDK launched.

Software Developer

• Researched and developed (ANSI C) systems programming for a storage controller
• Worked on RAID subsystem developing and researching features and testing tasks

T&T Engenheiros: February 2008 - June 2008

Worked as a contractor for Hewlett-Packard Brasil as a software developer using C in a project that involved porting the architecture of a large NAS controller operating system firmware.

Software Developer

• Researched and developed (ANSI C) systems programming for a storage controller
• Worked on RAID subsystem developing and researching features and testing tasks

Interage Informática: April 2005 - January 2008

Worked on Linux deployments/automations for security (Squid, Netfilter, Snort), e-mail (Sendmail, Procmail, SpamAssassin), and storage/authentication (SSH, Samba, Apache), and created from scratch a SOCKS4/5 (ANSI C / POSIX / pthreads) supporting pluggable modules (shared objects) with hooks to log and control custom protocols (e.g.: MSNP, Jabber, HTTP1).

Software engineer (C)

• Created a daemon from scratch (ANSI C / POSIX) for SOCKS4/5 proxy with plugins
• Created an engine for pluggins using shared objects (dlopen) for events/hooks
• Created plugins for protocols both proprietary (MSNP) and RFC based (XMPP)
• Created build and configuration support using GNU autoconf and automake
• Created custom event-based protocol using XML and asynchronous TCP responses
• Created support for transparent proxying for Linux (netfilter) and BSD (ipfw)
• Used Valgrind and related tools, OpenSSL and libevent

Sysadmin (Linux)

• Created shell scripts for automating Linux settings (daemons, networking)
• Created console interface (ncurses, dialog) to automate Linux deployment tasks
• Security: Netfilter rules, Snort settings, Nagios monitoring, IPSec for VPN
• E-mail: Sendmail for MTA, Procmail for automations, SpamAssassin and ClamAV
• HTTP: Apache and CGIs using Perl for automations of standard commands and files
• Proxy: Squid for HTTP filters and caching, dnsmasq for DNS, custom TCP balancer

Unisinos: February 2003 - March 2005

Researcher: Researching and creating artifacts for experiments in areas of mobile & pervasive and distributed computing, networking (ZeroConf) and language/frameworks. Contributed to papers (internal and published). Used Linux, C++, shell and make, gnuplot for plotting, and TeX/LaTeX.

Education

• Bachelor degree, Computer Science, Universidade do Vale do Rio dos Sinos
• TA: Programming and algorithms.

Open Source

• Before Git existed created patches to projects like BusyBox, pcap and coreutils
• In the early days of iOS open sourced an app to teach others UIKit/Objective-C