Jeff Kunzelman, Software Engineer

I build software the durable way

Jeff Kunzelman, a software engineer with 25+ years across native mobile, infrastructure automation, and low-level network security. I write compiled, tested code close to the metal, and I keep people's data on their own devices.

Three converging specialties, one engineering standard.

I've spent a career refusing the easy abstraction when the correct one costs more up front and pays back in performance, correctness, and years of supportability.

Native mobile

iOS & Android, test-first

10+ years of native iOS (Swift / SwiftUI / SwiftData, Objective-C) and now Kotlin 2.0 / Jetpack Compose / Room / Hilt, with a 1:1 unit-test parity rule between platforms and zero third-party UI dependencies.

Network security

802.11 & protocol analysis

Passive Wi-Fi monitoring in C99 from the kernel-facing code up: beacon / probe / deauth sniffing via nl80211, TLS ClientHello and JA3 fingerprinting, and per-alert pcap forensics.

DevOps & infra

Pipelines & agent ops

Multi-repo CI/CD with GitHub Actions, Debian packaging and auto-versioned releases, Linux VPS administration, BDD-tested tooling, and multi-agent AI operations platforms running on real production servers.

Apps I designed, built, and ship.

Three products that share a spine: compiled native code, tests as the contract, and data that stays where it belongs.

sloth · C99 · Linux · ncurses + libpcap + nl80211 Open source

sloth

Passive Wi-Fi & network security analysis

A fully passive forensic tool. It never injects packets, scans, or touches kernel state. 23 live ncurses views: 802.11 beacon / probe / deauth sniffing, ARP / mDNS / NBNS / DHCP / SSDP device discovery, TLS ClientHello and JA3 fingerprint capture, and synthesized alerts for port scans, deauth floods, NXDOMAIN bursts, threat-intel hits, and periodic beaconing. JSONL log and per-alert pcap for downstream analysis.

C99libpcapnl80211 ncursesJA3 / TLSCMake

LanguageC99, from the kernel-facing code up
Tests50 C unit tests plus a fake_platform shim
PosturePassive only: observe, never emit
OutputForensic JSONL + per-alert pcap

Source & releases →

Henge · iPhone + iPad + Mac · universal Live on the App Store

Henge

A photoreal Stonehenge that keeps real time.

The sun in Henge is not an animation. It is computed from the same ephemeris astronomers use, accurate across five thousand years, and the stones cast exactly the shadows that sun demands. The whole circle is raised on Salisbury Plain's surveyed ground, every stone carrying its Petrie number. A time machine runs from 3000 BC to AD 3000, and every archaeology claim carries its tier: Established, Debated, or Modern tradition, with sources one tap away.

SwiftiOS + iPadOS + macOS Real-time ephemerisNine languages No network

Henge on iPhone: midsummer sunrise on the solstice axis

PlatformsiPhone, iPad, and Mac, one unlock
Sky3000 BC to AD 3000, eclipses and standstills
PrivacyNo account, no network, no analytics
StatusShipped in 2026

Henge page → App Store →

MaterialsAndPractices · iOS · SwiftUI + Core Data + CloudKit Live on the App Store

Materials & Practices

Records & compliance for small-scale organic farms

A universal iPhone / iPad app for small organic growers: a USDA-sourced plant-cultivar database, grow management, soil-health monitoring with a pH spectrum and lab integration, agricultural lease management with payment tracking, worker time tracking with overtime detection, FDA FSMA harvest-safety checklists, and full traceability of organic amendments. Syncs across devices with CloudKit; fully localized in English and Spanish.

SwiftUICore DataCloudKit sync EN + ESFSMAZero deps

DomainOrganic certification & farm records
DataUSDA cultivars, soil labs, traceability
SyncNSPersistentCloudKitContainer
DepsApple frameworks only

App Store →

How I choose to build.

Not dogma. A set of trade-offs I've made deliberately and can defend.

→

Native over cross-platform

C / Swift / Kotlin over Flutter, React Native, Electron: smaller binaries, lower battery and memory cost, direct platform APIs, no framework treadmill.

→

Tests are the contract

1:1 unit-test parity across platforms; drift is caught by audit prompts and logged, never papered over. 22 XCTest suites mirrored by 30 JUnit suites on my current work.

→

Zero third-party deps

Apple frameworks on iOS; AndroidX, Room, and Hilt on Android. No Firebase, Retrofit, Glide, or RxJava. Nothing to abandon me at the next OS release.

→

Data stays on device

Encrypted vaults, no silent network, tamper-evident SHA-256 audit chains. Privacy as an architecture decision, not a policy page.

25+ years, from BlackBerry to multi-agent ops.

2025 to now Owner / Engineer · River.io LLC Shipping CareTime (native iOS + Android caregiver time-tracking with EVV and a SHA-256 audit chain), Henge, Materials & Practices, and sloth. Operating a multi-agent AI ops platform and OpenClaw agents that manage real-world rental units.

2024 to 2025 IT Specialist · VARC Inc. Automated Microsoft 365 administration via PowerShell and Microsoft Graph; built custom Copilot agents for HR and IT workflows.

2021 to 2024 IT Manager · Cosanti Foundation Ran network infrastructure across the Cosanti and Arcosanti sites; migrated web and VoIP to save $7.5K+/month; led fiber and Cat-6 upgrades at the historic site.

2021 to 2023 Lead iOS Developer · AgPilotX Agricultural-aviation guidance for iPad: Swift and MVVM integrated with aircraft hardware, Bluetooth/Wi-Fi valve controls, and heads-up displays.

2019 to 2020 Senior iOS Developer · Haulynx Long-haul trucking logistics: electronic driver logs, CI/CD with Bitrise, Splunk and Amplitude, and a Firebase to AWS GraphQL migration.

2016 to 2019 Lead Mobile Developer · GPS Insight · General Motors (Maven) Led an eight-month iOS rewrite of a fleet asset-tracking app; built test infrastructure and Concourse CI delivery for the Maven car-sharing app.

2009 to 2015 Senior Developer & Lead · AAA · Charles Schwab · Ashley Furniture Led an iOS/Android team with Pivotal Labs (BDD); built native IT-service-management clients and Splunk dashboards; launched the iAshley iPad catalog to 500+ stores.

1992 to 2009 Systems & Software Engineer · DHL · IBM · State of WA · Target · Thomson Reuters Principal systems engineering and BlackBerry sales/tracking apps; earlier programmer roles across enterprise and public-sector systems.

What I reach for.

LanguagesC99 / C11, C++, Swift, Objective-C, Kotlin 2.0, PowerShell

MobileSwiftUI, SwiftData, Jetpack Compose, Room, Hilt, CloudKit, Live Activities, Glance widgets

Systemsnl80211, libpcap, ncurses, TLS / JA3, Debian packaging, Linux VPS

DevOpsGitHub Actions, Bitrise, Concourse, cron orchestration, auto-versioned releases

EnterpriseMicrosoft Graph, M365 automation, REST APIs, ITIL (certified)

TestingXCTest, JUnit, Behave / Cucumber, Nimble / Quick, mutation testing